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Nucleic Acids and Genetics Study Guide

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Nucleic Acids and Genetics Study Guide

 

 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
Mendel verified true-breeding pea plants for certain traits before undertaking his experiments. The term "true-breeding" refers to:
a.
 genetically pure lines.
b.
 organisms that have a high rate of reproduction.
c.
 organisms that will produce identical copies of themselves upon reproduction.
d.
 organisms that are heterozygous for a given trait.
e.
 organisms that are homozygous for all possible traits.
 2.
Mating a true-breeding pink rose plant with a true-breeding pink rose plant will produce:
a.
 plants with pink, red, and white roses.
b.
 only plants with pink roses.
c.
 plants with red or white roses in a 3:1 ratio.
d.
 plants with white or red roses in a 3:1 ratio.
e.
 None of the above.
 3.
The term "dominant" means that:
a.
 both alleles can be expressed in a hybrid.
b.
 all members of the F2 generation of a hybrid cross exhibit the dominant phenotype.
c.
 one allele can mask the expression of another in a hybrid.
d.
 the dominant phenotype shows up in 100% of the offspring in all generations.
e.
 the dominant phenotype is more beneficial than the recessive phenotype.
 4.
Mendel's principle of segregation states that:
a.
 alleles from one parent mask the expression of alleles from the other parent.
b.
 alleles separate from each other before forming gametes.
c.
 hybrids will express a phenotype intermediate between the two parental phenotypes.
d.
 true-breeding parents produce offspring of the same phenotype.
e.
 different loci separate from each other.
 5.
A pear plant with the genotype Aa can produce gametes containing:
a.
 either A or Aa.
b.
 only the dominant A.
c.
 only the recessive a.
d.
 either A or a.
e.
 either AA, Aa or aa.
 6.
The physical appearance of an organism for a given trait is termed:
a.
 genetics.
b.
 dominance.
c.
 synapsis.
d.
 genotype.
e.
 phenotype.
 7.
The physical location of a particular gene on a chromosome is called:
a.
 an allele.
b.
 a locus.
c.
 a trait.
d.
 a chromatid.
e.
 None of the above.
 8.
____________ are alternative forms of a gene that govern the same feature, such as eye color, and occupy corresponding positions on homologous chromosomes.
a.
 Alleles
b.
 Loci
c.
 Homozygotes
d.
 Coupled traits
e.
 None of the above.
 9.
Using standard conventions for naming alleles, which of the following pairs is correct?
a.
 Tt—recessive phenotype
b.
 TT—heterozygous
c.
 tt—homozygous
d.
 tt—dominant phenotype
e.
 All of the above.
 10.
The separation of alleles of a gene takes place during:
a.
 anaphase of mitosis.
b.
 cytokinesis of mitosis.
c.
 anaphase I of meiosis.
d.
 telophase II of meiosis.
e.
 cytokinesis of meiosis.
 11.
Which of the following represents the possible genotype(s) resulting from a cross between an individual homozygous (BB) and one heterozygous (Bb) individual?
a.
 BB and Bb
b.
 BB, Bb, and bb
c.
 BB only
d.
 Bb only
e.
 bb only
 12.
Which of the following represents the possible genotype(s) resulting from a cross between two individuals that are heterozygous (Bb)?
a.
 BB and Bb
b.
 BB, Bb, and bb
c.
 BB only
d.
 Bb only
e.
 bb only
 13.
Which of the following represents the possible genotype(s) resulting from a cross between an individual heterozygous (Bb) and one that is homozygous (bb)?
a.
 BB and Bb
b.
 Bb, and bb
c.
 BB only
d.
 Bb only
e.
 bb only
 14.
Mating an individual expressing a dominant phenotype, but whose genotype is unknown, with an individual expressing the corresponding recessive phenotype is an example of:
a.
 a heterozygous cross.
b.
 an F1 cross.
c.
 an F2 cross.
d.
 a parental cross.
e.
 a test cross.
 15.
The genotype for a pea plant that is homozygous recessive for both height and pea color would be:
a.
 tt.
b.
 YY.
c.
 TtYy.
d.
 ttyy.
e.
 TTYY.
 16.
In peas, Mendel found that tall plants and yellow peas are dominant. The phenotype for a pea plant with the genotype TTyy would be:
a.
 heterozygous.
b.
 Ty.
c.
 short with yellow peas.
d.
 tall with green peas.
e.
 tall with yellow peas.
 17.
In peas, Mendel found that tall plants and yellow peas are dominant. The phenotype for a pea plant with the genotype TtYy would be:
a.
 heterozygous.
b.
 Ty.
c.
 short with yellow peas.
d.
 tall with green peas.
e.
 tall with yellow peas.
 18.
The height of pea plants from a cross between parent plants heterozygous for height, in which tall is dominant, would be:
a.
 all short.
b.
 all tall.
c.
 1 tall : 3 short.
d.
 2 short : 2 tall.
e.
 3 tall : 1 short.
 19.
Which of the following represents the possible genotype(s) resulting from a cross between an individual homozygous for black hair (BB) and an individual homozygous for blonde hair (bb)?
a.
 BB and Bb
b.
 BB, Bb, and bb
c.
 BB only
d.
 Bb only
e.
 bb only
 20.
What is the probability that two lizards that are heterozygous for stripes on their tails (Ss) will produce an offspring that is homozygous for no stripes (ss)?
a.
 1
b.
 1/2
c.
 1/4
d.
 1/8
e.
 0
 21.
In humans, assume that brown eyes is dominant and blue eyes is recessive. If two brown-eyed individuals have a child with blue eyes, that means:
a.
 both parents are homozygous for brown eyes.
b.
 both parents are heterozygous for eye color.
c.
 there is a 1/4 chance that their second child will have brown eyes.
d.
 there is a 50/50 chance that their second child will have blue eyes.
e.
 None of the above.
 22.
If a couple is planning on having two children, what is the probability that both will be male?
a.
 0
b.
 1/4
c.
 1/2
d.
 3/4
e.
 1
 23.
If a couple is planning on having three children, what is the probability that only one will be male?
a.
 0
b.
 1/4
c.
 3/8
d.
 1/2
e.
 3/4
 24.
A brown-eyed couple already has a child with blue eyes. What is the probability that their next child will have blue eyes, assuming that brown eyes is dominant and blue eyes is recessive?
a.
 0
b.
 1/4
c.
 1/2
d.
 3/4
e.
 1
 25.
A couple has already had 3 girls with cystic fibrosis, and were hoping to have a normal child for their fourth. What are the chances that the fourth child will be a normal male?
a.
 0
b.
 1/8
c.
 1/4
d.
 3/8
e.
 1/2
 26.
A brown-eyed couple heterozygous for eye color are planning on having two children. What is the probability that both children will have blue eyes, assuming brown eyes is dominant and blue eyes is recessive?
a.
 0
b.
 1/32
c.
 1/16
d.
 1/4
e.
 1/2
 27.
Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What is the probability that they will have a child with purple eyes?
a.
 1/1
b.
 1/2
c.
 1/4
d.
 3/4
e.
 0
 28.
Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What are the chances that the alien couple will have a child with red eyes?
a.
 1
b.
 1/2
c.
 1/4
d.
 3/4
e.
 0
 29.
Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What is the probability that the alien couple will have a child that is heterozygous for eye color?
a.
 1
b.
 1/2
c.
 1/4
d.
 3/4
e.
 0
 30.
The principle of independent assortment is not true for:
a.
 incomplete dominance.
b.
 mutations.
c.
 heterozygotes.
d.
 homozygotes.
e.
 X-linked genes.
 31.
The probability that two genes will be separated by crossing-over is related to:
a.
 the phenotype that they control.
b.
 how far the two genes are from the centromere.
c.
 the distance between the two genes on the chromosome.
d.
 whether the two genes are located on a sex chromosome.
e.
 how far the genes are from the kinetochore.
 32.
Genes that tend to be inherited together are said to be:
a.
 associated.
b.
 related.
c.
 similar.
d.
 linked.
e.
 alleles.
 33.
A ______________ is best used to demonstrate the linkage of two genes.
a.
 monohybrid cross
b.
 dihybrid cross
c.
 monohybrid test cross
d.
 two-allele test cross
e.
 two-point test cross
 34.
In genetics, map units express the distance between:
a.
 chromosomes during metaphase.
b.
 two loci on a chromosome.
c.
 alleles.
d.
 polar bodies.
e.
 homologous chromosomes.
 35.
In a two-point test cross, 36 of the offspring were recombinant types. The remaining 64 offspring were parental types. How many map units separate the two loci?
a.
 28
b.
 36
c.
 64
d.
 78
e.
 100
 36.
The sex of most mammals, birds, and insects is determined by:
a.
 the temperature.
b.
 the environment.
c.
 sex chromosomes.
d.
 chance.
e.
 None of the above.
 37.
The sex of a human is determined by:
a.
 the number of chromosomes.
b.
 the number of autosomes.
c.
 the presence of only one X chromosome.
d.
 the number of sex chromosomes.
e.
 the presence of Y chromosome.
 38.
The offspring of two heterozygous gray-bodied, normal-winged flies should be 50% gray-bodied/normal wings (BbRr) and 50% black-bodied/vestigial wings (bbrr) because these alleles are linked. If a small number, say 15%, of the offspring are instead black-bodied with normal wings, this is most likely the result of:
a.
 crossing-over.
b.
 incomplete dominance.
c.
 codominance.
d.
 an error in meiosis.
e.
 mutation.
 39.
An organism with the genotype of AaXx can produce gametes containing _________ if the two genes are unlinked.
a.
 either Aa or Xx
b.
 either AX, Ax, aX, ax
c.
 AaXx
d.
 AX or ax
e.
 None of the above.
 40.
A lizard with a striped tail is crossed with one having a spotted head, producing normal looking (no stripes or spots) lizard progeny. What progeny would be expected to be produced by mating these progeny with each other, if the genes conferring stripes and spots were on different chromosomes?
a.
 equal numbers of normal, striped, spotted and striped and spotted
b.
 3 striped : 1 spotted
c.
 9 striped and spotted : 3 spotted : 3 striped : 1 normal
d.
 9 striped : 3 spotted : 1 striped or spotted
e.
 9 normal : 3 striped : 3 spotted : 1 striped and spotted
 41.
A lizard with striped tails is crossed with one having a spotted head, producing normal looking (no stripes or spots) progeny. What progeny would be expected to be produced by mating one of these lizards with another that had a striped tail and spotted head, if the genes conferring stripes and spots were close together on the same chromosome?
a.
 equal numbers of normal, striped, spotted and striped and spotted
b.
 3 striped : 1 spotted
c.
 mostly progeny that are striped or spotted
d.
 mostly progeny that are normal or striped and spotted
e.
 9 normal : 3 striped : 3 spotted : 1 striped and spotted
 42.
Why is color-blindness more common in males than in females?
a.
 Because females would have to receive two copies of the recessive color blindness gene to actually express the trait.
b.
 Because a male only needs to receive the recessive gene from his mother to be color-blind.
c.
 Because color-blindness is an X-linked trait.
d.
 All of the above.
e.
 None of the above.
 43.

What are the possible phenotypes of the children if the mother has Type A blood and the father has type AB blood? (Use the Punnett square to verify your answer.)

 

a.
 all AB
b.
 A, B
c.
 A, AB
d.
 A, B, AB
e.
 A, B, O
 44.

What are the possible phenotypes of the children if the mother's genotype is IAi for blood type and the father is IBi? (Use the Punnett square to verify your answer.)

 

a.
 all AB
b.
 A, B
c.
 A, AB
d.
 A, B, O
e.
 A, B, AB, O
 45.

What are the predicted phenotypes of the male children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Use the Punnett square to verify your answer.)

 

a.
 all normal
b.
 3 normal : 1 hemophilia
c.
 1 hemophilia : 1 normal
d.
 1 hemophilia : 3 normal
e.
 all hemophiliacs
 46.

What are the predicted phenotypes of the female children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Use the Punnett square to verify your answer.)

 

a.
 all carriers
b.
 3 homozygous normal : 1 carrier
c.
 1 homozygous normal : 1 carrier
d.
 1 hemophilia: 2 homozygous normal : 1 carrier
e.
 all hemophiliacs
 47.
What are the possible genotypes of a female child from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics?
a.
 XHXH or XHXh
b.
 XHXh
c.
 XHYH
d.
 Hh
e.
 HH
 48.
A Barr body in a mammalian female cell represents:
a.
 an inactivated oocyte.
b.
 a polar body.
c.
 a degenerate nucleus.
d.
 an inactivated X chromosome.
e.
 an inactivated Y chromosome.
 49.
Calico cats are never male because:
a.
 recessive genes are not usually expressed on their X chromosome.
b.
 male hormones prevent expression of the calico phenotype.
c.
 two different X chromosomes are needed for the expression of the calico phenotype.
d.
 two different Y chromosomes are needed for the expression of the calico phenotype.
e.
 one X chromosome and one Y chromosome are needed for the expression of the calico phenotype.
 50.
A diploid individual has a maximum of ____________ different alleles for a particular locus.
a.
 one
b.
 two
c.
 three
d.
 four
e.
 more than four
 51.
A particular gene that controls seed coat color in peas also determines the susceptibility of these peas to a particular disease. This situation is referred to as:
a.
 variegation.
b.
 additive dominance.
c.
 codominance.
d.
 pleiotropy.
e.
 incomplete dominance.
 52.
When certain medium height hybrid plants were crossed, they produced offspring that were dwarf, medium, and tall in a ratio of 1 : 2 : 1. This is an example of:
a.
 variegation.
b.
 hybrid vigor.
c.
 incomplete dominance.
d.
 epistasis.
e.
 a polygenic trait.
 53.
Breeding a yellow dog with a brown dog produced puppies with both yellow and brown hairs intermixed. This is an example of:
a.
 variegation.
b.
 codominance.
c.
 incomplete dominance.
d.
 epistasis.
e.
 a polygenic trait.
 54.
A gene that affects, prevents, or masks the expression of a gene at another locus is a(n) _________ gene.
a.
 recessive
b.
 dominant
c.
 epistatic
d.
 codominant
e.
 plieotropic
 55.
The range of phenotypic possibilities that can develop from a certain dog genotype under different environmental conditions is called the:
a.
 epistatic interaction.
b.
 norm of reaction.
c.
 nurture limit.
d.
 genotype range.
e.
 maximum phenotype.
 56.
________________________ refers to multiple independent pairs of genes having similar and additive effects on the same characteristic.
a.
 Codominance
b.
 Epistasis
c.
 Polygenic inheritance
d.
 Complete dominance
e.
 Additive dominance
 57.
In the experiments of Griffith, the conversion of non-lethal R-strain bacteria to lethal S-strain bacteria:
a.
 was the result of genetic mutation.
b.
 was an example of the genetic exchange known as transformation.
c.
 supported the case for proteins as the genetic material.
d.
 could not be reproduced by other researchers.
e.
 was an example of conjugation.
 58.
The first experimenters to use Griffith's transformation assay to identify the genetic material were:
a.
 Meselson and Stahl.
b.
 Watson and Crick.
c.
 Franklin and Wilkins.
d.
 Avery, MacLeod, and McCarty.
e.
 Hershey and Chase.
 59.
The bacteriophages used in Alfred Hershey's and Martha Chase's experiments showed that:
a.
 DNA was injected into bacteria.
b.
 DNA and protein were injected into bacteria.
c.
 DNA remained on the outer coat of bacteria.
d.
 proteins were injected into bacteria.
e.
 proteins were responsible for the production of new viruses within the bacteria.
 60.
The main reason scientists thought that proteins, rather than DNA, were the carriers of genetic material in the cell was:
a.
 their presence within the nucleus.
b.
 their abundance within the cell.
c.
 the large number of possible amino acid combinations.
d.
 their ability to self replicate within the cytoplasm.
e.
 their ability to be exported from the cell.
 61.
Which of the following statements about DNA is false?
a.
 DNA is capable of forming many different sequences.
b.
 DNA contains thymine instead of uracil.
c.
 DNA is double-stranded rather than single-stranded.
d.
 DNA is only found in eukaryotic cells.
e.
 DNA contains the sugar deoxyribose.
 62.
The information carried by DNA is incorporated in a code specified by the:
a.
 phosphodiester bonds of the DNA strand.
b.
 number of separate strands of DNA.
c.
 size of a particular chromosome.
d.
 specific nucleotide sequence of the DNA molecule.
e.
 number of bases in a DNA strand.
 63.
X-ray diffraction studies are used to determine:
a.
 the sequence of amino acids in protein molecules.
b.
 the sequence of nucleic acids in nucleic acid molecules.
c.
 the distances between atoms of molecules.
d.
 the type of chemical under investigation.
e.
 the wavelength of light emitted by chemicals.
 64.
The two molecules that alternate to form the backbone of a polynucleotide chain are:
a.
 adenine and thymine.
b.
 cytosine and guanine.
c.
 sugar and phosphate.
d.
 base and sugar.
e.
 base and phosphate.
 65.
______________________ used x-ray diffraction to provide images of DNA.
a.
 Watson and Crick
b.
 Crick and Wilkins
c.
 Franklin
d.
 Franklin and Crick
e.
 Watson and Wilkins
 66.
______________________ determined the structure of the molecule DNA.
a.
 Crick and Wilkins
b.
 Watson and Crick
c.
 Franklin and Crick
d.
 Franklin
e.
 Watson, Crick, and Wilkins
 67.
Chargaff determined that DNA from any source contains about the same amount of guanine as __________.
a.
 uracil
b.
 thymine
c.
 adenine
d.
 cytosine
e.
 guanine
 68.
X-ray crystallography showed that DNA:
a.
 had the bases in the center of the molecule.
b.
 had the sugars and phosphates on the outside of the molecule.
c.
 was a very long molecule.
d.
 was made of 2 strands.
e.
 was a helix.
 69.
Why is DNA able to store large amounts of information?
a.
 It contains a large number of different nucleotides.
b.
 Its nucleotides can be arranged in a large number of possible sequences.
c.
 It is capable of assuming a wide variety of shapes.
d.
 The sugar and phosphates can be arranged in many different sequences.
e.
 The nucleotides can be altered to form many different letters in the sequence.
 70.
In DNA, the genetic information:
a.
 is contained in each strand.
b.
 is contained in only one of the strands.
c.
 is contained in both strands together.
d.
 is contained in the differences between the 2 strands.
e.
 None of the above.
 71.
Two chains of DNA must run in ____________ direction(s) and must be ____________ if they are to bond with each other.
a.
 the same; uncomplementary
b.
 opposite; uncomplementary
c.
 parallel; uncomplementary
d.
 parallel; complementary
e.
 antiparallel; complementary
 72.
Hydrogen bonds can form between guanine and ____________, and between adenine and ____________.
a.
 phosphate; sugar
b.
 thymine; cytosine
c.
 cytosine; thymine
d.
 sugar; phosphate
e.
 adenine; guanine
Figure 11-01
Use the figure below to answer the corresponding questions.nar001-1.jpg
 73.
The portion of the molecule in box 5 of Figure 11-01 is:
a.
 a hydrogen bond.
b.
 a phosphate.
c.
 a nucleotide.
d.
 a pyrimidine.
e.
 a protein.
 74.
In Figure 11-01, the portion of the molecule in box _________ is a pyrimidine.
a.
 1
b.
 3
c.
 4
d.
 1 and 3
e.
 3 and 4
 75.
The portion of the molecule in box 3 of Figure 11-01 is:
a.
 a sugar.
b.
 a protein.
c.
 a pyrimidine.
d.
 a purine.
e.
 a nucleotide.
 76.
Which of the following nucleotide sequences represents the complement to the DNA strand 5´ - AGATCCG- 3´?
a.
 5´ – AGATCCG- 3´
b.
 3´ – AGATCCG- 5´
c.
 5´ – CTCGAAT- 3´
d.
 3´ – CTCGAAT- 5´
e.
 3´ – TCTAGGC- 5´
 77.
How is a single strand of DNA able to serve as a template for the synthesis of another strand?
a.
 Nucleotides pair with those of the original strand to form a new strand.
b.
 Hydrogen bonds holding the two strands together are easy to break, allowing one strand to be a template.
c.
 A single strand of DNA is not able to serve as a template.
d.
 One strand of DNA directs the synthesis of a new strand on its partner.
e.
 Both A and B.
 78.
Which of the following best describes semiconservative replication?
a.
 The translation of a DNA molecule into a complementary strand of RNA.
b.
 A DNA molecule consists of one parental strand and one new strand.
c.
 The number of DNA molecules is doubled with every other replication.
d.
 The replication of DNA never takes place with 100% accuracy.
e.
 The replication of DNA takes place at a defined period in the cell cycle.
 79.
Who first confirmed that the replication of DNA was semiconservative?
a.
 Chargaff and Hershey
b.
 Watson and Crick
c.
 Avery and Griffith
d.
 Meselson and Stahl
e.
 Watson, Crick, and Wilkins
 80.
If DNA replication rejoined the 2 parental strands, it would be termed:
a.
 dispersive.
b.
 gradient.
c.
 semiconservative.
d.
 parental.
e.
 conservative.
 81.
Meselson and Stahl separated DNA from different generations using:
a.
 density gradient centrifugation.
b.
 gel electrophoresis.
c.
 an electron microscope.
d.
 differential radioisotope labeling.
e.
 None of the above.
 82.
When a DNA molecule containing a wrong base at one location in one strand is replicated:
a.
 the mutation is corrected by the DNA polymerase enzyme.
b.
 the mutation is ignored by the DNA polymerase enzyme.
c.
 the mutation is copied into one of the two daughter molecules.
d.
 the mutation is copied into both of the daughter molecules.
e.
 the replication is stopped.
 83.
What prevents knot formation in replicating DNA?
a.
 protosomes
b.
 topoisomerases
c.
 scaffolding proteins
d.
 chromatin
e.
 histones
 84.
Why does DNA synthesis only proceed in the 5´to 3´ direction?
a.
 Because DNA polymerases can only add nucleotides to the 3´ end of a polynucleotide strand.
b.
 Because the 3´ end of the polynucleotide molecule is more electronegative than the 5´ end.
c.
 Because that is the direction in which the two strands of DNA unzip.
d.
 Because that is the only direction that the polymerase can be oriented.
e.
 Because the chromosomes are always aligned in the 5´ to 3´ direction in the nucleus.
 85.
How is the chromosome of a bacterial cell replicated?
a.
 The linear DNA molecule is replicated from multiple origins of replication bidirectionally.
b.
 The linear DNA molecule is replicated from one origin of replication bidirectionally.
c.
 The circular DNA molecule is replicated from multiple origins of replication bidirectionally.
d.
 The circular DNA molecule is replicated from one origin of replication bidirectionally.
e.
 The circular DNA molecule is replicated from one origin of replication unidirectionally.
 86.
How are the chromosomes of a eukaryote cell replicated?
a.
 The linear DNA molecules are replicated from multiple origins of replication bidirectionally.
b.
 The linear DNA molecules are replicated from one origin of replication bidirectionally.
c.
 The circular DNA molecules are replicated from multiple origins of replication bidirectionally.
d.
 The circular DNA molecules are replicated from one origin of replication bidirectionally.
e.
 The linear DNA molecules are replicated from one origin of replication unidirectionally.
 87.
Which of the following adds new nucleotides to a growing DNA chain?
a.
 DNA polymerase
b.
 DNA helicase
c.
 RNA primer
d.
 primase
e.
 RNA polymerase
 88.
Which of the following cause the unwinding of the DNA double helix?
a.
 DNA polymerase
b.
 DNA helicase
c.
 RNA primer
d.
 primosome
e.
 RNA polymerase
 89.
In DNA replication, the lagging strand:
a.
 is synthesized as a series of Okazaki fragments.
b.
 is synthesized as a complementary copy of the leading strand.
c.
 pairs with the leading strand by complementary base pairing.
d.
 is made up entirely of RNA primers.
e.
 is not synthesized until the synthesis of the leading strand is completed.
Figure 11-02
Use the figure below to answer the corresponding questions.nar002-1.jpg
 90.
The correct designation for the DNA strand labeled C in Figure 11-02 is:
a.
 the leading strand.
b.
 3´.
c.
 Okazaki fragments.
d.
 polymerase.
e.
 None of the above.
 91.
The segments labeled F in Figure 11-02 are responsible for:
a.
 linking short DNA segments.
b.
 synthesizing the leading strand.
c.
 forming the replication fork.
d.
 initiating DNA synthesis.
e.
 unwinding the DNA double helix.
 92.
The enzyme represented by the letter D in Figure 11-02 is responsible for:
a.
 linking short DNA segments.
b.
 synthesizing the leading strand.
c.
 forming the replication fork.
d.
 forming nucleosomes.
e.
 unwinding the DNA double helix.
 93.
The structures represented by the letter E in Figure 11-02 are called:
a.
 leading fragments
b.
 Okazaki fragments.
c.
 replication forks.
d.
 nucleosomes.
e.
 DNA polymerases.
 94.
In replication, once the DNA strands have been separated, reformation of the double helix is prevented by:
a.
 DNA helicase enzyme.
b.
 helix-destabilizing proteins.
c.
 DNA polymerases.
d.
 ATP.
e.
 GTP.
 95.
Enzymes called ____________ form nicks in the DNA molecules to prevent the formation of knots in the DNA helix during replication.
a.
 topoisomerases
b.
 helix-destabilizing enzymes
c.
 DNA polymerases
d.
 RNA polymerases
e.
 DNA ligases
 96.
The DNA strand that is replicated smoothly and continuously is called the:
a.
 primary strand.
b.
 first strand.
c.
 leading strand.
d.
 alpha strand.
e.
 lagging strand.
 97.
The final product of DNA replication is:
a.
 mRNA, tRNA, and rRNA molecules.
b.
 a wide variety of proteins.
c.
 DNA fragments.
d.
 two DNA molecules, each of which contains one new and one old DNA strand.
e.
 the enzymes needed for further processes, such as DNA polymerase.
 98.
A replication fork:
a.
 is only seen in prokaryotic chromosomes.
b.
 is only seen in bacterial cells.
c.
 is a Y-shaped structure where both DNA strands are replicated simultaneously.
d.
 is a site where one DNA strand serves as a template, but the other strand is not replicated.
e.
 is created by the action of the enzyme RNA polymerase.
 99.
The 5´ end of each Okazaki fragment begins with:
a.
 the same RNA primer that began synthesis on the leading strand.
b.
 a DNA primer binding to the template DNA.
c.
 DNA polymerase binding to the template DNA.
d.
 a separate RNA primer.
e.
 a small DNA primer.
 100.
Okazaki fragments are joined together by:
a.
 RNA polymerase.
b.
 DNA ligase.
c.
 DNA polymerase.
d.
 RNA ligase.
e.
 primase.
 101.
Primase is the enzyme responsible for:
a.
 unwinding the DNA double strand to allow DNA polymerase access to the template DNA.
b.
 introducing nicks into the DNA double strand in order to prevent the formation of knots.
c.
 hydrolyzing ATP to facilitate DNA unwinding.
d.
 making short strands of RNA at the site of replication initiation.
e.
 forming a replication fork in the DNA double helix.
 102.
____________, the ends of eukaryotic chromosomes, shorten with every cell replication event.
a.
 Centromeres
b.
 Telomeres
c.
 Kinetochores
d.
 Primosomes
e.
 Nucleosomes
 103.
The ends of eukaryotic chromosomes can be lengthened by:
a.
 apoptosis.
b.
 reverse transcriptase.
c.
 primase.
d.
 telomerase.
e.
 DNA polymerase.
 104.
Cancer cells differ from noncancerous cells in that:
a.
 they have elevated levels of telomerase.
b.
 they are virtually immortal.
c.
 they have the ability to resist apoptosis.
d.
 they can maintain telomere length as they divide.
e.
 All of the above.
 105.
In 1998, Bodnar and her colleagues found that by introducing genes coding for telomeres into cultured human cells:
a.
 the cells underwent more cell divisions than normal.
b.
 the cells underwent fewer cell divisions than normal.
c.
 the cells all lived indefinitely.
d.
 the cells underwent gene expression more vigorously.
e.
 the cell cycle shortened.
 106.
Which of the following is not a reason why Neurospora is an ideal organism to study the effects of genetic mutations?
a.
 Neurospora is easy to grow.
b.
 Neurospora grows as a haploid organism.
c.
 Neurospora is easy to genetically manipulate.
d.
 Neurospora reproduces both sexually and asexually.
e.
 Neurospora contains homologous chromosomes that are easily viewed with a light microscope.
 107.
Garrod first proposed that:
a.
 metabolic defects were due to a lack of an enzyme.
b.
 metabolic defects were due to excess enzyme.
c.
 metabolic defects were due to chromosomal changes.
d.
 mutations were inheritable.
e.
 metabolic defects did not occur in humans.
 108.
Why was it important in the studies of Beadle and Tatum that Neurospora is haploid?
a.
 Because it is easier to grow haploid molds in the laboratory.
b.
 Because haploid molds have simpler nutritional requirements than do diploid molds.
c.
 Because a mutation that arises is not masked by a normal allele on a homologous chromosome.
d.
 Because haploid Neurospora will always mutate.
e.
 Because diploid Neurospora will always mutate.
 109.
Beadle and Tatum began their studies with wild-type Neurospora, which is:
a.
 Neurospora that only grows in the wild.
b.
 a mutant strain that will only grow in the lab on complete medium.
c.
 a strain that will not grow in the lab.
d.
 a virulent strain of Neurospora.
e.
 a normal phenotype that will grow on minimal medium.
 110.
Beadle and Tatum irradiated Neurospora and initially grew the mutant strains on complete medium. How were they able to determine what type of mutation each strain had?
a.
 By growing the mold on a complete medium with extra vitamins and nutrients.
b.
 By growing the mold on minimal media supplemented with different combinations of amino acids, vitamins, etc.
c.
 By growing the mold in its diploid form to see which traits were masked.
d.
 By comparing Neurospora to other species of mold.
e.
 By observing the marked differences in morphology between the different strains.
 111.
What conclusions did Beadle and Tatum reach with their studies of Neurospora?
a.
 Each mutant gene affected several enzymes.
b.
 Each mutant gene affected a pair of enzymes.
c.
 Each mutant gene affected only one enzyme.
d.
 Mutant genes had no effect on the enzymes produced by the cells.
e.
 None of the above.
 112.
Linus Pauling demonstrated that:
a.
 the structure of hemoglobin was altered by a mutation of a single gene.
b.
 mutations only caused defects in enzymes.
c.
 mutations alter the structure of RNA, but not proteins.
d.
 mutations were inherited.
e.
 the structure of hemoglobin was altered by mutations in any of a dozen genes.
Figure 12-01
Use the figure below to answer the corresponding questions.nar003-1.jpg
 113.
The experimental design in Figure 12-01 was used to examine:
a.
 the relationship between genetic changes and metabolic enzymes.
b.
 the mutation rate of Neurospora.
c.
 resistance of Neurospora to genetic poisons.
d.
 toxicity of arginine metabolites.
e.
 growth of Neurospora in the presence of different antibiotics.
 114.
The conclusion associated with mutant strain III in Figure 12-01 was that:
a.
 it contained all the enzymes needed for normal metabolism.
b.
 it was missing all the enzymes for metabolism of amino acids.
c.
 it was missing an enzyme for metabolism and could not synthesize arginine.
d.
 it was missing an enzyme for metabolism and could not synthesize citrulline.
e.
 it was missing an enzyme for metabolism and could not synthesize ornithine.
 115.
One of the mRNA codons specifying the amino acid leucine is 5´-CUA-3´. Its corresponding anticodon is:
a.
 5´-GAT-3´.
b.
 3´-AUC-5´.
c.
 3´-GAU-5´.
d.
 3´-GAT-5´.
e.
 5´-GAU-3´.
 116.
Which of the following is a characteristic of uracil?
a.
 The ability to bond with adenine.
b.
 The ability to bond with guanine.
c.
 It is a purine.
d.
 The ability to bond with cytosine.
e.
 It contains two nitrogenous rings.
 117.
RNA differs from DNA in all the following except:
a.
 RNA is single stranded and DNA is double stranded.
b.
 RNA is a larger molecule than DNA.
c.
 RNA contains uracil and DNA contains thymine.
d.
 RNA contains ribose and DNA contains deoxyribose.
e.
 None of the above.
 118.
Ribose differs from deoxyribose by having:
a.
 two attached bases.
b.
 one less oxygen.
c.
 an extra hydroxyl group.
d.
 an extra carbon in the ring.
e.
 None of the above.
 119.
Uracil forms a complementary pair with ____________ in RNA and _____________ in DNA.
a.
 adenine; adenine
b.
 adenine; thymine
c.
 thymine; thymine
d.
 uracil; adenine
e.
 adenine; uracil
 120.
RNA synthesis is also known as:
a.
 elongation.
b.
 reverse transcription.
c.
 termination.
d.
 translation.
e.
 transcription.
 121.
All RNA except for _________ is made from DNA.
a.
 tRNA
b.
 mRNA
c.
 rRNA
d.
 snRNA
e.
 None of the above.
 122.
The total number of different three-base combinations of the four nucleic acid bases is:
a.
 12.
b.
 16.
c.
 20.
d.
 64.
e.
 256.
 123.
During protein synthesis, ribosomes:
a.
 attach to the mRNA molecule and travel along its length.
b.
 attach to the DNA molecule and travel along its length to produce an mRNA molecule.
c.
 translate mRNA into tRNA.
d.
 transcribe mRNA to tRNA.
e.
 translate mRNA into DNA.
 124.
How is the four-letter language of nucleic acids converted into the 20-word language of amino acids?
a.
 The 4 nucleic acid bases combine in 2-letter combinations that define different amino acids.
b.
 The 4 nucleic acid bases combine in 3-letter sequences that define different amino acids.
c.
 Triplets of the 2-letter nucleic acid bases are translated into the 20 different amino acids.
d.
 The 4 bases each specify 1 amino acid, which give rise to the remaining 16 amino acids.
e.
 The 4 bases are first converted into tRNA molecules, which can each attach to 5 amino acids.
 125.
Why is only one strand of DNA transcribed into mRNA?
a.
 Because mRNA is only required in small quantities.
b.
 Because transcribing both DNA strands would produce different amino acid sequences.
c.
 Because the other strand would produce the same amino acid sequence in reverse order.
d.
 Because all genes are located on the same DNA strand, while the other strand acts as protection.
e.
 Because the other strand is transcribed directly into amino acids.
 126.
Initiation of transcription requires:
a.
 a promoter sequence.
b.
 DNA polymerase.
c.
 an RNA primer.
d.
 a DNA primer.
e.
 Okazaki fragments.
 127.
A sequence of bases located upstream from a reference point occurs:
a.
 towards the 3´ end of the amino acid sequence.
b.
 towards the 5´ end of the mRNA sequence.
c.
 towards the 3´ end of the mRNA sequence.
d.
 towards the 5´ end of the transcribed DNA strand.
e.
 towards the carboxyl end of the amino acid sequence.
 128.
How does the first nucleotide at the 5´ end of a new mRNA chain differ from the other nucleotides in the chain?
a.
 The first nucleotide is always a uracil.
b.
 The first nucleotide is always a cytosine.
c.
 The first nucleotide retains its triphosphate group, while the others do not.
d.
 The first nucleotide does not retain its triphosphate group, while the others in the chain do.
e.
 The first nucleotide is always a modified cytosine.
Figure 12-02
Use the figure below to answer the corresponding questions.nar004-1.jpg
 129.
In Figure 12-02, the transcription process begins at the area labeled:
a.
 A.
b.
 D.
c.
 E.
d.
 G.
e.
 None of the above.
 130.
The component labeled B in Figure 12-02 is:
a.
 DNase.
b.
 DNA polymerase.
c.
 RNA primase.
d.
 RNA polymerase.
e.
 reverse transcriptase.
 131.
The transcript in Figure 12-02 is labeled:
a.
 D.
b.
 C.
c.
 G.
d.
 H.
e.
 A.
 132.
The process illustrated in Figure 12-02 is:
a.
 DNA synthesis.
b.
 translation.
c.
 transcription.
d.
 a frame shift mutation.
e.
 protein synthesis.
 133.
Leader sequences contain signals that:
a.
 prevent enzymes from degrading the newly synthesized mRNA.
b.
 inhibit ribosome binding until the appropriate time.
c.
 initiate chain termination.
d.
 allow the ribosomes to be properly positioned to translate the message.
e.
 allow tRNA molecules to successfully bind to mRNA.
 134.
Aminoacyl-tRNA synthetases ________ link ________ to their respective tRNA molecules.
a.
 ionically; mRNAs
b.
 loosely; mRNAs
c.
 terminally; codons
d.
 covalently; amino acids
e.
 enzymatically; codons
 135.

Which of the following numbered terms represents the correct order of sequences in a prokaryotic mRNA molecule as it was synthesized?

1. 3´ trailing sequences
2. coding sequences
3. leader sequences
4. termination signals
a.
 1 ® 2 ® 3 ® 4
b.
 3 ® 2 ® 4 ® 1
c.
 2 ® 1 ® 4 ® 3
d.
 4 ® 2 ® 1 ® 3
e.
 3 ® 4 ® 2 ® 1
 136.
Which of the following serves as an "adapter" in protein synthesis and bridges the gap between mRNA and proteins?
a.
 tRNA
b.
 cDNA
c.
 rRNA
d.
 promoter sequences
e.
 DNA
 137.
The codon is found in the:
a.
 template strand of DNA.
b.
 non-template strand of DNA.
c.
 mRNA.
d.
 tRNA.
e.
 rRNA.
 138.
The tRNA:
a.
 must be recognized by ribosomes.
b.
 must have an anticodon.
c.
 must have an attachment site for the amino acid.
d.
 must be recognized by a specific aminoacyl-tRNA synthetase that adds the correct amino acid.
e.
 All of the above.
 139.

Which of the following numbered events represents the correct sequence of events of prokaryotic translation initiation?

1. large ribosomal subunit binds to initiation complex
2. initiation tRNA binds small ribosomal subunit
3. initiation complex binds to ribosome recognition sequence on mRNA
a.
 1 ® 2 ® 3
b.
 1 ® 3 ® 2
c.
 2 ® 1 ® 3
d.
 2 ® 3 ® 1
e.
 3 ® 2 ® 1
 140.
Where is the amino-acid binding site located on the tRNA molecule?
a.
 in the middle of the loop
b.
 at the end of a "stem" that is the 3´ end of the molecule
c.
 in the first loop
d.
 along the longest stretch of base pairing in the molecule
e.
 on the 5´ end of the molecule
Figure 12-03
Use the figure below to answer the corresponding questions.nar005-1.jpg
 141.
In Figure 12-03, the portion of the molecule in the figure that contains the anti-codon is:
a.
 1.
b.
 2.
c.
 3.
d.
 4.
e.
 5.
 142.
In Figure 12-03, the portion of the molecule labeled 5 is:
a.
 the attached amino acid.
b.
 a double-stranded region.
c.
 a single-stranded region.
d.
 the anti-codon.
e.
 the codon.
 143.
The enzyme peptidyl transferase, which catalyzes the transfer of the polypeptide chain attached to the tRNA in the ____________ site to the aminoacyl-tRNA in the ____________ site, is thought to be a(an) ____________ molecule and not a protein.
a.
 A; P; rDNA
b.
 P; A; tRNA
c.
 A; P; mRNA
d.
 P; A; rRNA
e.
 P; A; sugar
 144.
Translocation is the process whereby the __________ moves in order to place the tRNA bound to the growing polypeptide chain in the __________ site, thereby freeing the __________ site for a new aminoacyl-tRNA.
a.
 mRNA; A; P
b.
 ribosome; P; A
c.
 tRNA; P; A
d.
 ribosome; A; P
e.
 tRNA; A; P
 145.
Following peptide bond formation between the amino acid in the A site on the ribosome and the growing polypeptide chain, the tRNA in the A site:
a.
 releases the growing polypeptide chain.
b.
 picks up another amino acid to add to the chain.
c.
 moves to the P site of the ribosome.
d.
 forms a peptide bond with A site of the ribosome.
e.
 forms a covalent bond with the P site of the ribosome.
 146.
If a human gene mRNA were placed into a cell of yeast, it would be:
a.
 degraded immediately.
b.
 translated into a repeating amino acid chain.
c.
 translated into a chain of random amino acids not resembling the protein in humans.
d.
 translated into the protein that is found in humans.
e.
 integrated into the genome of the yeast.
 147.
In all organisms, the AUG codon codes for:
a.
 the initiation of translation.
b.
 the termination of transcription.
c.
 the termination of chain elongation.
d.
 the amino acid valine.
e.
 a termination tRNA molecule.
 148.
A polyribosomes is:
a.
 a complex of many ribosome and an mRNA.
b.
 a complex of many ribosomes in eukaryotes.
c.
 an initiation complex in eukaryotes.
d.
 an elongation complex in eukaryotes.
e.
 a complex of a ribosome with its two subunits and several mRNAs.
 149.
Introns in pre mRNA are known to:
a.
 code for specific protein domains.
b.
 undergo excision, whereby they are spliced out of the message.
c.
 be able to move within the mRNA, thereby giving rise to new exon combinations.
d.
 protect pre mRNA from enzyme degradation.
e.
 code for important amino acid sequences.
 150.
Proteins synthesized in E. coli have which of the following at their amino terminal end?
a.
 N-formyl-methionine
b.
 N-acetyl-adenine
c.
 adenine triphosphate
d.
 the AUG codon
e.
 the UUU codon
 151.
The wobble hypothesis states that:
a.
 more than one ribosome can bind to an mRNA molecule.
b.
 some amino acids are coded for by more than one codon.
c.
 there is more than one stop codon in the genetic code.
d.
 a particular amino acid may be linked to more than one type of tRNA molecule.
e.
 certain tRNA anticodons can pair with more than one codon sequence.
 152.
Binding of the appropriate aminoacyl-tRNA to the A site requires:
a.
 no additional energy.
b.
 the input of two ATP molecules to supply the needed energy.
c.
 energy supplied by GTP.
d.
 activation of the A site.
e.
 phosphorylation of the tRNA molecule.
 153.
Translocation in translation requires:
a.
 no additional energy.
b.
 activation of the P site.
c.
 the input of two ATP molecules to supply the needed energy.
d.
 energy supplied by GTP.
e.
 phosphorylation of the mRNA molecule.
 154.
Interrupted coding sequences include long sequences of bases that do not code for amino acids. These noncoding sequences, called ____________, are found in ____________ cells.
a.
 exons; prokaryotic
b.
 introns; prokaryotic
c.
 exons; eukaryotic
d.
 introns; eukaryotic
e.
 None of the above.
 155.
An mRNA "5´ cap":
a.
 prevents translation.
b.
 facilitates binding of ribosomes.
c.
 marks the mRNA for degradation.
d.
 decreases the half-life of the mRNA.
e.
 protects newly synthesized mRNA from degradation.
 156.
The 3´ end of eukaryotic pre-mRNAs are changed by:
a.
 removing the last phosphate group.
b.
 adding a "cap."
c.
 copying the last few bases so that it can form a duplex structure.
d.
 cutting and adding 100-250 adenine nucleotides.
e.
 phosphorylation of the mRNA molecule.
 157.
Walter Gilbert proposed that exons are:
a.
 remnants of older life forms.
b.
 sequences that code for protein domains that are shuffled to form new proteins.
c.
 the result of mutation of introns.
d.
 not present in prokaryotes.
e.
 sequences that interrupt the coding sequences of proteins.
 158.
Retroviruses or RNA tumor viruses use __________ to make DNA:
a.
 DNA polymerase
b.
 DNA-dependent RNA polymerase
c.
 RNA polymerase
d.
 primase
e.
 reverse transcriptase
 159.
Substitution of one base pair for another can result in a ____________ mutation that results in the conversion of an amino acid specifying codon to a termination codon.
a.
 nonsense
b.
 frameshift
c.
 chromosomal
d.
 missense
e.
 None of the above.
 160.
A mutation that replaces one amino acid in a protein with another is called a ____________ mutation.
a.
 frameshift
b.
 recombinant
c.
 nonsense
d.
 missense
e.
 neutral
 161.
Frameshift mutations result from:
a.
 the substitution of one base pair for another.
b.
 the substitution of more than one base pair.
c.
 the insertion or deletion of one or two base pairs.
d.
 the substitution of a stop codon for an amino acid-specifying codon.
e.
 the substitution of a start codon for an amino acid codon.
 162.
A gene can now be defined as:
a.
 a DNA sequence that carries information to produce a specific RNA or protein product.
b.
 a DNA nucleotide sequence that carries information to produce a specific polypeptide.
c.
 a DNA or RNA sequence that carries information to produce a single polypeptide.
d.
 a DNA nucleotide sequence that carries information to produce an enzyme.
e.
 a DNA or RNA sequence that carries information to produce a specific polypeptide.

 
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Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.
 1.
Atoms have a positive charge. _________________________
 2.
Electrons have very little mass. _________________________
 3.
Molecules are atoms that have gained or lost one or more electrons. _________________________
 4.
An atom with more electrons than protons has a positive charge. _________________________
 5.
A covalent bond forms between two atoms that share electrons to form a molecule. _________________________
 6.
Water molecules attract nonpolar molecules such as oil. _________________________
 7.
The ability of water to retain heat helps cells maintain a constant internal temperature. _________________________
 8.
The role of carbohydrates in cells is to supply energy. _________________________
 9.
RNA is made up of a double strand of nucleotides. _________________________
 10.
When cells break down food, the energy from the food is temporarily stored as ATP. _________________________
 11.
The amount of energy needed to cause a chemical reaction to start is called activation energy. _________________________
 12.
Without enzymes, chemical reactions necessary for life would not occur quickly or easily enough to sustain life. _________________________
 13.
When an enzyme binds with its substrate, the activation energy needed for the chemical reaction to occur is increased. _________________________
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 14.
Atoms are not composed of
a.
 protons.
c.
 electrons.
b.
 neutrons.
d.
 chemical bonds
 15.
The electrons of an atom
a.
 are found in the nucleus along with the protons.
b.
 occupy the space surrounding the nucleus.
c.
 have a positive charge.
d.
 are attached to the positive charge of neutrons.
 16.
The smallest particle of matter that can retain the chemical properties of carbon is a carbon
a.
 molecule.
c.
 atom.
b.
 macromolecule.
d.
 element.
 17.
A substance that is composed of only one type of atom is called a(n)
a.
 compound.
c.
 element.
b.
 cell.
d.
 molecule.
 18.
All matter is composed of
a.
 cells.
c.
 atoms.
b.
 molecules.
d.
 carbon.
 19.
Covalent bonds form when
a.
 two molecules of water share electrons.
b.
 a molecule of water becomes an ion.
c.
 two hydrogen atoms share electrons with one oxygen atom.
d.
 two hydronium ions are attracted to each other.
 20.
Ionic bonds form between particles that have
a.
 opposite charges.
c.
 no charges.
b.
 the same charge.
d.
 neutral charges.
 21.
The bond formed when two atoms share a pair of electrons is called a(n)
a.
 hydrogen bond.
c.
 covalent bond.
b.
 ionic bond.
d.
 water bond.
 22.
Sharing of electrons in the outer energy levels of two atoms
a.
 results in ion formation.
b.
 makes both atoms stable.
c.
 only occurs if both are atoms of the same element.
d.
 is found only among carbon atoms.
 23.
A molecule that has a partial positive charge on one side and a partial negative charge on the other side is called a(n)
a.
 nonpolar molecule.
c.
 charged molecule.
b.
 polar molecule.
d.
 ion.
 24.
Nonpolar molecules have
a.
 no negative or positive ends.
c.
 only a negative end.
b.
 both negative and positive ends.
d.
 only a positive end.
 25.
When placed in the same container, oil and water do not mix because
a.
 they are both polar.
c.
 they are both nonpolar.
b.
 water is polar and oil is nonpolar.
d.
 water is nonpolar and oil is polar.
 26.
Attractions between water molecules are called
a.
 covalent bonds.
c.
 polar bonds.
b.
 ionic bonds.
d.
 hydrogen bonds.
 27.
Water is a polar molecule because
a.
 it contains two hydrogen atoms for each oxygen atom.
b.
 it has a charge.
c.
 different parts of the molecule have slightly different charges.
d.
 it does not have a charge.
 28.
Which is not a unique property of water?
a.
 Frozen water floats.
b.
 Water retains a large amount of heat.
c.
 Water molecules stick to each other.
d.
 Water cools rapidly.
 29.
Acidic solutions have a pH that is
a.
 less than 7.
c.
 a negative number.
b.
 between 7 and 14.
d.
 more than 7.
 30.
Hydronium ions, H+, react with hydroxide ions, OH-, to form
a.
 water.
c.
 a base.
b.
 an acid.
d.
 a buffer.
 31.
Which of the following is not a large biomolecule?
a.
 carbohydrate
c.
 lipid
b.
 ice
d.
 nucleic acid
 32.
The building blocks of most biomolecules contain the element
a.
 carbon.
c.
 calcium.
b.
 nitrogen.
d.
 sodium.
 33.
Which of the following molecules are classified as carbohydrates?
a.
 amino acids
c.
 nucleotides
b.
 fats
d.
 sugars
 34.
Polysaccharides are
a.
 carbohydrates.
c.
 proteins.
b.
 lipids.
d.
 nucleic acids.
nar001-1.jpg
nar001-2.jpg
Molecule A
Molecule B
 35.
Refer to the illustration above. Molecule A is a
a.
 carbohydrate.
c.
 nucleic acid.
b.
 lipid.
d.
 protein.
 36.
Plants store glucose in the form of
a.
 starch.
c.
 cellulose.
b.
 glycogen.
d.
 chitin.
 37.
Which of the following is a carbohydrate?
a.
 ATP
c.
 wax
b.
 steroid
d.
 sucrose
 38.
Lipids are
a.
 soluble in water.
b.
 made of chains of amino acids.
c.
 linked together with peptide bonds.
d.
 used by the body for storing energy.
 39.
All of the following are examples of lipids except
a.
 oil.
c.
 steroids.
b.
 starch.
d.
 candle wax.
 40.
Which molecules are most closely related to lipids?
a.
 amino acids
b.
 long chains of carbon and hydrogen
c.
 nucleotides
d.
 sugars
 41.
Which of the following molecules are most closely related to proteins?
a.
 amino acids
c.
 nucleotides
b.
 monosaccharides
d.
 sugars
 42.
Long chains of amino acids are found in
a.
 carbohydrates.
c.
 proteins.
b.
 lipids.
d.
 sugars.
 43.
The overall shape of a single chain of amino acids in a protein is that protein’s
a.
 primary structure.
c.
 tertiary structure.
b.
 secondary structure.
d.
 quaternary structure.
 44.
The amino group of one amino acid is linked to the carboxyl group of another amino acid in a protein. This link is a(n)
a.
 peptide bond.
c.
 ionic bond.
b.
 hydrogen bond.
d.
 polar bond.
 45.
What gives each amino acid its unique properties?
a.
 its side group
c.
 its carboxyl group
b.
 its amino group
d.
 its sequence
 46.
The two types of nucleic acids are
a.
 RNA and ATP.
c.
 DNA and ATP.
b.
 DNA and RNA.
d.
 nucleotides and ATP.
 47.
Which of the following molecules are most closely related to nucleic acids?
a.
 amino acids
c.
 nucleotides
b.
 fats
d.
 sugars
 48.
DNA stores
a.
 fat.
c.
 energy.
b.
 carbohydrates.
d.
 hereditary information.
 49.
The two strands of a DNA molecule are held together by
a.
 ionic bonds.
c.
 hydrogen bonds.
b.
 covalent bonds.
d.
 peptide bonds.
 50.
Which of the following is not part of a nucleotide in a DNA molecule?
a.
 three phosphate groups
c.
 a base
b.
 a sugar
d.
 a phosphate group
 51.
ATP (adenosine triphosphate) stores energy in the bonds between its
a.
 hydrogen atoms.
c.
 nucleotides.
b.
 carbon atoms.
d.
 phosphate groups.
 52.
When paper burns, the paper combines with oxygen to form carbon dioxide and water vapor. How does the mass of carbon dioxide plus water vapor compare with the mass of the paper plus oxygen?
a.
 The mass of carbon dioxide plus water vapor is greater than that of paper plus oxygen.
b.
 The mass of carbon dioxide plus water vapor is less than that of paper plus oxygen.
c.
 It is impossible to tell.
d.
 The mass of carbon dioxide plus water vapor is identical to that of paper plus oxygen.
 53.
The law of conservation of energy states that energy cannot be
a.
 changed from one form to another.
b.
 taken from the surroundings in a reaction.
c.
 released into the surroundings in a reaction.
d.
 created or destroyed in a chemical reaction.
 54.
A chemical reaction will probably occur between two substrate molecules if they
a.
 are far apart.
b.
 are aligned in the wrong spatial orientation.
c.
 have large amounts of kinetic energy.
d.
 have little kinetic energy.
 55.
Reducing activation energy
a.
 is a violation of the laws of nature.
b.
 requires higher temperatures than those found within cells.
c.
 occurs only when reactants are quickly added to the reaction mixture.
d.
 is accomplished by the action of enzymes on reactants.
nar002-1.jpg
 56.
Refer to the illustration above. Which of the following statements regarding the graph is true?
a.
 Reaction 2 occurs faster than Reaction 3 because Reaction 2 requires more energy than Reaction 3.
b.
 The difference between the graphs shown for Reaction 2 and Reaction 3 occurs because of a difference in the activation energy of these reactions.
c.
 Reactant A contains more energy at the beginning of the reaction than product C has at the end of the reaction.
d.
 Product B contains more energy at the end of the reaction than reactant A has at the beginning of the reaction.
 57.
Refer to the illustration above. Reaction 3 in the graph
a.
 probably occurred in the presence of an enzyme.
b.
 requires more activation energy than Reaction 2.
c.
 is the same as Reaction 1, but faster.
d.
 is slower than Reaction 2.
 58.
The molecule on which an enzyme acts is called a(n)
a.
 active site.
c.
 polar molecule.
b.
 inactive site.
d.
 substrate.
 59.
An enzyme
a.
 is used up in a reaction.
b.
 raises the activation energy of a reaction.
c.
 bonds with an active site on a substrate molecule.
d.
 lowers the activation energy of a reaction.
 60.
Enzymes
a.
 are able to heat up molecules so that they can react.
b.
 always provide carbon dioxide for chemical reactions.
c.
 hold substrate molecules in the correct alignment.
d.
 absorb excess heat so that reactions occur at low temperatures.
 61.
A cell contains
a.
 thousands of different kinds of enzymes, each assisting in a different chemical reaction.
b.
 one kind of enzyme that assists in thousands of different chemical reactions.
c.
 approximately 100 kinds of enzymes, each assisting in a different chemical reaction.
d.
 one enzyme that assists in reactions involving protein substrates and one enzyme that assists in reactions involving substrates that are not proteins.
 

Completion
Complete each statement.
 62.
The negatively charged particles in an atom are ____________________.
 63.
Protons and neutrons are found in the ____________________ of an atom.
 64.
A(n) ____________________ is a group of atoms held together by covalent bonds.
 65.
Sodium chloride, NaCl, is an example of a(n) _________________.
 66.
A(n) ____________________ bond forms between two atoms sharing electrons.
 67.
The attraction between oppositely charged ions results in the formation of a(n) ____________________.
 68.
Weak chemical attractions between polar molecules are ____________________ bonds.
 69.
Lipids are ____________________ molecules because they have no negative and positive poles.
 70.
Water heats and cools ____________________.
 71.
The attraction that causes water and other liquids to form drops and thin films is ____________________.
 72.
The medium in which most cellular events take place is ____________________.
 73.
Substances with a pH less than 7 are ____________________.
 74.
Substances with a pH greater than 7 are ____________________.
 75.
The pH scale measures the concentration of ____________________ ions in solutions.
 76.
A carbon atom can bond with four other atoms because it has ____________________ valence electrons.
 77.
A(n) ____________________ contains carbon, hydrogen, and oxygen in a ratio of 1:2:1.
 78.
Amino acids are the building blocks of __________________.
 79.
Most proteins consist of two or more ________________ that twist and fold around each other.
 80.
Long chains of nucleotides are called ____________________.
 81.
The ability to move or change matter is ____________________.
 82.
All living things require a source of ____________________ to carry out their life activities.
 83.
The starting materials for chemical reactions are called ____________________, while the new substances that are formed are called ____________________.
 84.
The energy needed to start a chemical reaction is called ____________________.
 85.
A biochemical reaction can be speeded up by adding a(n) ____________________, which lowers the amount of activation energy required to start the reaction.
 86.
The portion of an enzyme molecule into which a specific substrate can fit is called the ____________________.
 

Short Answer
 87.
How many different kinds of atoms are there in an element?
 88.
How does an atom become an ion?
 89.
An ionic bond forms between what two kinds of particles?
 90.
What makes a water molecule polar?
 91.
How well do nonpolar molecules dissolve in water?
 92.
What is an attraction between particles of different substances called?
 93.
What are the two most common elements found in large biomolecules?
 94.
What is the function of lipids in cells?
 95.
What determines the primary structure of a protein?
 96.
Where do your cells get most of the energy they need for metabolism?
 97.
How do enzymes speed up a chemical reaction?
 

Problem
 98.

The following statements are about the molecule ATP (adenosine triphosphate). For each statement, first determine whether it is true or false. Then, if it is false, rewrite the statement so that it is correct.

a. ATP is chemically similar to a carbohydrate.
b. Cells require ATP to function.
c. None of the energy in food molecules is stored in ATP.
d. ATP is the primary source of energy for chemical reactions occurring in all cells of all living organisms.

nar003-1.jpg
 99.

Refer to the illustration above. The graph depicts the relative energy levels of the products and reactants for the following chemical reaction: A + B « C + D.

a. Which substances, A, B, C, and/or D, are present at point 1 on the graph?
b. Which substances, A, B, C, and/or D, are present at point 3 on the graph?
c. Why is point 2 at a higher energy level than point 1?
d. Why is point 3 at a lower energy level than point 1?
e. Draw a dashed line on the graph indicating how the energy level of this reaction over time would be different if the enzyme that catalyzes the reaction were not present.

Enzymes catalyze a variety of biological reactions. The extent to which they can speed up the rate of a reaction is dependent on a number of factors. Draw a graph for the following condition(s), showing the effect of altering one factor on the relative rate of a reaction. Use “0” to indicate no activity, and “1” through “10” to indicate increasing rate of reaction from very low to very high. Include a label for your graph(s).
 100.
Refer to the paragraph above, and then draw your graph in the space below. Enzyme #1 is inactive between 0°C and 10°C. It is active above 10°C, with the rate increasing steadily until the temperature reaches 40°C. At 40°C, the rate of the reaction is very high. Above 40°C, the rate decreases steadily until the temperature reaches 60°C, at which point the enzyme is no longer active.
 101.
Refer to the paragraph above, and draw your graph. Enzyme #2 is inactive at a pH of 1–4. It is active above a pH of 4, with the rate increasing slowly until the pH reaches 6. Above a pH of 6, the rate increases sharply until the pH reaches 7. Above a pH of 7, the rate decreases sharply until the pH reaches 8. Above a pH of 8, the rate decreases gradually until the pH reaches 10, at which point the enzyme is no longer active.
 102.
Refer to the paragraph above, and draw your graph. Enzyme #3 is inactive when the concentration of the substrate it acts upon is zero. The enzyme is active when the substrate concentration is above zero, with the rate increasing only very slightly until the concentration reaches 30%. Above 30%, the rate increases very sharply to a high level, until the concentration reaches 60%. Above a concentration of 60%, the rate increases very little. The rate does not increase when the substrate concentration is above 80%.
 

Essay
 103.
Describe how an enzyme can function in speeding up a chemical reaction within a cell.

 
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Chapter 4 Cell Structure Study Guide

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Chapter 4 Cell Structure Study Guide

 

  

Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.
 
 1.
Robert Hooke first observed cells by looking at a thin slice of cork under a microscope. _________________________
 


 
 2.
Mathias Schleiden concluded that cells make up every part of a plant. _________________________
 


 
 3.
Differences in the colors of cells enable different cells to perform different functions. _________________________
 


 
 4.
All cells have a cell wall that surrounds them. _________________________
 


 
 5.
All multicellular organisms are made up of prokaryotic cells. _________________________
 


 
 6.
The cells of animals are prokaryotic. _________________________
 


 
 7.
The cytoskeleton is a web of protein fibers in eukaryotic cells. _________________________
 


 
 8.
Substances made in the nucleus, such as RNA messages, move into the nucleolus by passing through nuclear pores. _________________________
 


 
 9.
Flattened, membrane-bound sacs that package and distribute proteins are called the Golgi apparatus. _________________________
 


 
 10.
Ribosomes attached to the smooth ER make proteins. _________________________
 


 
 11.
Lysosomes contain specific enzymes that break down large molecules, such as food particles. _________________________
 


 
 12.
Ribosomes are the sites of ATP production in animals. _________________________
 


 
 13.
Most of a cell’s ATP is produced in the cell’s mitochondria. _________________________
 


 
 14.
A typical animal cell contains one or more chloroplasts. _________________________
 


 
 15.
A chloroplast is an organelle that uses light energy to make sugar from carbon dioxide and water. _________________________
 


 
 16.
Prokaryotes are always multicellular organisms. _________________________
 


 
 17.
Many prokaryotes have flagella that allow them to attach to surfaces. _________________________
 


 
 18.
A tissue is a distinct group of cells that have similar structures and functions. _________________________
 


 
 19.
A leaf is made up of different tissues that work together. _________________________
 


 
 20.
In multicellular organisms, a single cell must carry out all of the organism’s activities. _________________________
 


 
 21.
A unicellular organism is composed of many individual, permanently associated cells that coordinate their activities. _________________________
 


 
 22.
Colonial organisms are unicellular organisms that can live as a connected group or survive when separated. _________________________
 


 
 23.
Some protists and most fungi have a multicellular body. _________________________
 


 
 24.
Most multicellular organisms begin as a single cell. _________________________
 


 
  

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 
 25.
Which of the following led to the discovery of cells?
a.
 electricity
c.
 microscopes
b.
 computers
d.
 calculators
 
 26.
Which of the following is part of the cell theory?
a.
 All living things are made of one cell.
b.
 Cells are the basic units of structure and function in organisms.
c.
 Most cells arise from existing cells.
d.
 Cells are nonliving units that make up organisms.
 
 27.
When the volume of a cell increases, its surface area
a.
 increases at the same rate.
c.
 increases at a faster rate.
b.
 remains the same.
d.
 increases at a slower rate.
 
 28.
Surface area is an important factor in limiting cell growth because
a.
 the cell can burst if the membrane becomes too large.
b.
 materials cannot enter the cell if it is too large.
c.
 the cell may become too large to take in enough food and to remove enough wastes.
d.
 waste products cannot leave the cell if it is too small.
 
 29.
The size to which cells can grow is limited by their
a.
 location.
c.
 function.
b.
 structure.
d.
 surface area-to-volume ratio.
 
 30.
As cell size increases, the surface area-to-volume ratio
a.
 decreases.
c.
 increases then decreases.
b.
 increases.
d.
 remains the same.
 
 31.
To function most efficiently, a cell’s size must be
a.
 large.
c.
 small.
b.
 medium.
d.
 any size.
 
 32.
Which of the following shapes would allow a cell to have the greatest surface area-to-volume ratio?
a.
 sphere
c.
 egg-shaped
b.
 cube
d.
 broad and flat
 
 33.
A cube with a side length of 6 mm has a surface area-to-volume ratio of
a.
 1:1.
c.
 3:1.
b.
 2:1.
d.
 6:1.
 
 34.
One difference between prokaryotes and eukaryotes is that prokaryotes do not have
a.
 DNA.
c.
 cytoplasm.
b.
 a cell membrane.
d.
 a nucleus.
 
 35.
Which cells have a cell membrane, cytoplasm, ribosomes, and DNA?
a.
 only animal cells
c.
 only eukaryotic cells
b.
 only prokaryotic cells
d.
 all cells
 
 36.
The genetic material that provides instructions for making proteins is
a.
 DNA.
c.
 cytoplasm.
b.
 cytosol.
d.
 a ribosome.
 
 37.
A structure within a eukaryotic cell that carries out specific activities inside the cell is called a(n)
a.
 organelle.
c.
 nucleus.
b.
 cytoplasm.
d.
 membrane.
 
 38.
Which of the following statements about prokaryotes is correct?
a.
 They have a nucleus.
b.
 Their evolution preceded that of eukaryotes.
c.
 The organelles in their cytoplasm are surrounded by membranes.
d.
 They are multicellular organisms.
 
 39.
Only eukaryotic cells have
a.
 DNA.
c.
 ribosomes.
b.
 membrane-bound organelles.
d.
 cytoplasm.
 
   
 
nar001-1.jpg
 
 40.
Refer to the illustration above. Which structure acts as a boundary between the outside environment and the inside of the cell?
a.
 structure 1
c.
 structure 3
b.
 structure 2
d.
 structure 4
 
 41.
Refer to the illustration above. Which structure immediately identifies this cell as a eukaryote?
a.
 structure 1
c.
 structure 3
b.
 structure 2
d.
 structure 4
 
 42.
Refer to the illustration above. In eukaryotic cells, DNA is found in
a.
 structure 1.
c.
 structure 3.
b.
 structure 2.
d.
 structure 5.
 
 43.
Refer to the illustration above. Structure 2 is
a.
 rough endoplasmic reticulum.
c.
 a mitochondrion.
b.
 a Golgi apparatus.
d.
 the nucleus.
 
 44.
Refer to the illustration above. Which structure produces vesicles filled with proteins?
a.
 structure 1
c.
 structure 4
b.
 structure 2
d.
 structure 5
 
 45.
Refer to the illustration above. Structure 5 is
a.
 part of the endoplasmic reticulum.
c.
 a mitochondrion.
b.
 a Golgi apparatus.
d.
 the nucleus.
 
 46.
Refer to the illustration above. The cell uses structure 3 to
a.
 transport material from one part of the cell to another.
b.
 package proteins so they can be stored by the cell.
c.
 use light energy to make sugar.
d.
 use energy from organic compounds to make ATP.
 
 47.
Refer to the illustration above. The cell shown is probably an animal cell because it
a.
 has mitochondria.
c.
 has a cell membrane.
b.
 does not have a cell wall.
d.
 does not have a nucleus.
 
 48.
Microfilaments, microtubules, and intermediate fibers are three kinds of cytoskeleton
a.
 protein fibers.
c.
 organelles.
b.
 membranes.
d.
 DNA.
 
 49.
What kind of cytoskeleton fibers could help a cell change shape to fit into a space?
a.
 microfilaments
c.
 intermediate fibers
b.
 microtubules
d.
 tubulin fibers
 
 50.
Which of the following is true of both DNA and some proteins?
a.
 made in nucleus
b.
 made in ribosomes
c.
 must be kept separate from cytoplasm
d.
 must be kept separate from nucleus
 
 51.
cell : cell membrane ::
a.
 nucleus : DNA
c.
 organelle : cell
b.
 nucleus : nuclear envelope
d.
 cell : DNA
 
 52.
The double membrane surrounding the nucleus is called the
a.
 nucleolus.
c.
 ribosome.
b.
 nuclear wall.
d.
 nuclear envelope.
 
 53.
In a cell, proteins are made on the
a.
 mitochondria.
c.
 nucleus.
b.
 ribosomes.
d.
 cell membrane.
 
 54.
Where are bound ribosomes located?
a.
 suspended in the cytosol
b.
 inside the nucleus
c.
 attached to membranes of another organelle
d.
 outside the cell membrane
 
 55.
The organelle that moves proteins and other substances through the cell is the
a.
 endoplasmic reticulum.
c.
 Golgi apparatus.
b.
 mitochondrion.
d.
 cytoplasm.
 
 56.
The organelle that modifies, sorts, and packages proteins is the
a.
 endoplasmic reticulum.
c.
 lysosome.
b.
 ribosome.
d.
 Golgi apparatus.
 
   
 
nar002-1.jpg
 
 57.
Refer to the illustration above. The structures labeled 4 are
a.
 vesicles.
c.
 ribosomes.
b.
 lysosomes.
d.
 chloroplasts.
 
 58.
Refer to the illustration above. Which structure packages proteins for distribution?
a.
 structure 1
c.
 structure 3
b.
 structure 2
d.
 structure 4
 
 59.
Refer to the illustration above. Structure 3 is a(n)
a.
 mitochondrion.
c.
 ribosome.
b.
 endoplasmic reticulum.
d.
 vesicle.
 
 60.
Plant cells have a large membrane-bound compartment in which water, waste products, and nutrients can be stored. This compartment is called the
a.
 mitochondrion.
c.
 Golgi apparatus.
b.
 chloroplast.
d.
 central vacuole.
 
 61.
A cell that requires a lot of energy might contain large numbers of
a.
 chromosomes.
c.
 mitochondria.
b.
 vacuoles.
d.
 lysosomes.
 
 62.
The organelles associated with plant photosynthesis are the
a.
 mitochondria.
c.
 Golgi apparatus.
b.
 chloroplasts.
d.
 vacuoles.
 
 63.
sunlight : chloroplasts ::
a.
 chloroplasts : lysosomes
c.
 organic compounds : ribosomes
b.
 organic compounds : mitochondria
d.
 ATP : vesicles
 
 64.
What do chloroplasts and mitochondria have in common?
a.
 absorption of light energy
c.
 production of ATP
b.
 presence in all cells
d.
 digestion of cell wastes
 
 65.
All the following are found in both plant and animal cells, except
a.
 a cell wall.
c.
 mitochondria.
b.
 a cell membrane.
d.
 endoplasmic reticulum.
 
 66.
Short, thick outgrowths that allow prokaryotes to attach to surfaces or each other are called
a.
 flagella.
c.
 microfilaments.
b.
 microtubules.
d.
 pili.
 
 67.
Which of the following is an example of a prokaryotic cell?
a.
 chloroplast
c.
 bacterium
b.
 fungus
d.
 muscle cell
 
 68.
Which of the following pairs contains unrelated items?
a.
 eukaryote-plant
c.
 cell wall-animal cell
b.
 ribosome-protein
d.
 mitochondria-ATP
 
 69.
What level of organization is the small intestine?
a.
 cell
c.
 organ
b.
 tissue
d.
 organ system
 
 70.
Which of the following statements about colonial organisms is correct?
a.
 They are multicellular.
b.
 Their cell activities are integrated.
c.
 They are a collection of different kinds of cells.
d.
 They can survive when separated.
 
  

Completion
Complete each statement.
 
   71.
All cells arise from ____________________.
 
 

 
   72.
The basic unit of structure and function in an organism is the ____________________.
 
 

 
   73.
The statement that “cells arise only from existing cells” is part of the ____________________.
 
 

 
   74.
As a cell’s size decreases, its surface area-to-volume ratio ____________________.
 
 

 
   75.
The surface area-to-volume ratio limits a cell’s ____________________.
 
 

 
   76.
Eukaryotic cells contain specialized structures called ____________________.
 
 

 
   77.
A cell with a nucleus is a(n) ____________________ cell.
 
 

 
   78.
Scientists think that ____________________ cells evolved about 1.5 billion years ago.
 
 

 
   79.
All substances that enter or leave a cell must cross the cell ____________________.
 
 

 
   80.
The ____________________ houses a cell’s DNA, which contains genetic material.
 
 

 
   81.
The organelles where protein synthesis occurs in a cell are called ____________________.
 
 

 
   82.
Prokaryotic cells have a cell ____________________ that surrounds the cell membrane.
 
 

 
   83.
Some prokaryotic cells have a ____________________ that surrounds the cell wall.
 
 

 
   84.
____________________ cells have a system of internal membranes that divides the cytoplasm into compartments.
 
 

 
   85.
The web of protein fibers that supports the shape of the cell is called the ____________________.
 
 

 
   86.
The cytoskeleton’s network of ____________________ fibers anchors cell organelles.
 
 

 
   87.
A ribosome is made of ____________________ and many proteins.
 
 

 
   88.
DNA instructions are copied as ____________________ messages.
 
 

 
   89.
Ribosomes use RNA messages to assemble ____________________.
 
 

 
   90.
The ____________________ is a structure that makes ribosome parts in the nucleus.
 
 

 
   91.
Rough endoplasmic reticulum has ____________________ attached to its surface.
 
 

 
   92.
____________________ endoplasmic reticulum has no attached ribosomes.
 
 

 
   93.
Vesicles that contain newly made proteins move through the ____________________ from the ER to the Golgi apparatus.
 
 

 
   94.
Vesicles help maintain ____________________ by storing and releasing various substances as the cell needs them.
 
 

 
   95.
Lysosomes work by fusing with other ____________________.
 
 

 
   96.
Photosynthesis takes place in the ____________________ of plant cells.
 
 

 
   97.
Both plant cells and animal cells have cell membranes. In addition, plant cells are surrounded by a(n) ____________________.
 
 

 
   98.
In multicellular organisms, similar cells group together to make ____________________.
 
 

 
   99.
A group of identical cells that can survive alone if separated are called ____________________ organisms.
 
 

 
  

Short Answer
 
   100.
Why did it take more than 150 years for scientists to appreciate the discoveries of Hook and Leeuwenhoek?
 

 
   101.
What are the three parts of the cell theory?
 

 
   102.
What happens to a cell’s surface area-to-volume ratio as the cell gets larger?
 

 
   103.
How can a large cell have a large surface area-to-volume ratio?
 

 
   104.
What is the difference in the location of DNA in a prokaryotic cell and in a eukaryotic cell?
 

 
   105.
What is the function of organelles in eukaryotic cells?
 

 
   106.
Describe the characteristics of DNA in a prokaryotic cell.
 

 
   107.
What are three kinds of cytoskeleton in eukaryotic cells?
 

 
   108.
What are three functions of the cytoskeleton?
 

 
   109.
Where are ribosome parts made and assembled?
 

 
   110.
What kind of ribosomes makes proteins that remain inside the cell?
 

 
   111.
How does the appearance of the two kinds of endoplasmic reticulum differ? What causes the difference?
 

 
   112.
What happens to the vesicle membrane of a vesicle that migrates to the cell membrane and releases proteins to the outside of the cell?
 

 
   113.
What is the function of a contractile vacuole in a protist?
 

 
   114.
Describe what happens in a protist after the cell membrane surrounds food outside the cell.
 

 
   115.
What is the difference between the energy source of chloroplasts and mitochondria? What do the two organelles have in common?
 

 
   116.
Compare the functions of flagella and pili in prokaryotes.
 

 
   117.
What are three structures present in plant cells but not in animal cells?
 

 
   118.
What are the levels of organization of cells in a multicellular organism?
 

 
   119.
How does a multicellular organism develop from a single cell?
 

 
  

Essay
 
   120.
Small cells function more efficiently than large cells do. Briefly explain why this is true, using the concept of surface area-to-volume ratio.
 

 
   121.
Describe the making of a ribosome. Include the difference between the two kinds of ribosomes.
 

 
   122.
Describe the movement of proteins through the internal membrane system of a cell.
 

 

 

 
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Chapter 5 – Cell Transport Study Guide

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Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.
 1.
One way that cells maintain homeostasis is by controlling the movement of substances across the cell membrane. _________________________
 2.
The cell membrane is made up of a double layer called the DNA bilayer. _________________________
 3.
A phospholipid is made up of a lipid “head” and two fatty acid “tails.” _________________________
 4.
The nonpolar tails of a phospholipid are attracted to water. _________________________
 5.
Cell-surface markers face the inside of the cell. _________________________
 6.
A concentration gradient exists when one area has a higher concentration of a substance than another area does. _________________________
 7.
The movement down a concentration gradient is called diffusion. _________________________
 8.
When the solute concentration outside a cell is equal to the solute concentration inside the cell, the cell’s environment is hypotonic. _________________________
 9.
A cell placed in a high salt solution would swell because of osmosis. _________________________
 10.
Osmosis is the diffusion of starch molecules through a selectively permeable membrane. _________________________
 11.
To pass through a cell membrane, water requires carrier proteins. _________________________
 12.
Facilitated diffusion is an active process that requires a cell to expend a great deal of energy. _________________________
 13.
Passive transport uses ATP to move molecules against their concentration gradient. _________________________
 14.
Exocytosis is a process that uses vesicles to capture substances and bring them into a cell. _________________________
 15.
Cells use exocytosis to export proteins modified by the Golgi apparatus. _________________________
 16.
Cells communicate by sending chemical signals that carry information to other cells. _________________________
 17.
Receptor proteins bind only to signals that match the specific color of the binding site. _________________________
 18.
Receptor proteins may cause the formation of a second messenger molecule inside the cell. _________________________
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 19.
cell membrane : cell ::
a.
 window : house
c.
 door : house
b.
 roof : house
d.
 wall : house
 20.
Which type of molecule forms the cell membrane?
a.
 protein
c.
 nucleic acid
b.
 phospholipid
d.
 carbohydrate
 21.
Phospholipids are molecules that have
a.
 one polar phosphate head and two polar fatty acid tails.
b.
 one polar phosphate head and two nonpolar fatty acid tails.
c.
 one polar phosphate head and one polar fatty acid tail.
d.
 one nonpolar phosphate head and two polar fatty acid tails.
 22.
The interior of the lipid bilayer of a cell membrane forms a nonpolar zone that
a.
 allows most polar molecules to pass through the membrane.
b.
 allows food to pass through the membrane.
c.
 repels ions and most polar molecules.
d.
 makes the membrane permeable to most molecules.
nar001-1.jpg
 23.
Refer to the illustration above. The structure labeled A is composed of
a.
 lipids.
c.
 proteins.
b.
 carbohydrates.
d.
 DNA.
 24.
Refer to the illustration above. The structure labeled D is a(n)
a.
 cell-surface marker.
c.
 enzyme.
b.
 receptor protein.
d.
 transport protein.
 25.
Refer to the illustration above. The structure labeled C is a(n)
a.
 cell-surface marker.
c.
 enzyme.
b.
 receptor protein.
d.
 transport protein.
 26.
Proteins in the cell membrane that identify the cell are called
a.
 cell-surface markers.
c.
 enzymes.
b.
 receptor proteins.
d.
 transport proteins.
 27.
As a result of diffusion, the concentration of many types of substances
a.
 always remains greater inside a membrane.
b.
 eventually becomes balanced on both sides of a membrane.
c.
 always remains greater outside of a membrane.
d.
 becomes imbalanced on both sides of a membrane.
nar002-1.jpg
 28.
Refer to the illustration above. The process shown is called
a.
 osmosis.
c.
 active transport.
b.
 facilitated diffusion.
d.
 diffusion.
 29.
Diffusion is the movement of a substance
a.
 only through a lipid bilayer membrane.
b.
 from an area of low concentration to an area of higher concentration.
c.
 only in liquids.
d.
 from an area of high concentration to an area of lower concentration.
 30.
The dispersal of ink in a beaker of water is an example of
a.
 diffusion.
c.
 active transport.
b.
 osmosis.
d.
 endocytosis.
 31.
Proteins that serve as tunnels for specific substances through the lipid bilayer are
a.
 cell-surface markers.
c.
 receptor proteins.
b.
 channel proteins.
d.
 enzymes.
 32.
Sugar molecules cross the cell membrane by
a.
 active transport.
c.
 osmosis.
b.
 facilitated diffusion.
d.
 simple diffusion.
 33.
Which of the following does not require energy?
a.
 diffusion
c.
 active transport
b.
 endocytosis
d.
 sodium-potassium pump
 34.
Ions move through ion channels by
a.
 endocytosis.
c.
 passive transport.
b.
 simple diffusion.
d.
 active transport.
 35.
The diffusion of water into or out of a cell is called
a.
 solubility.
c.
 selective transport.
b.
 osmosis.
d.
 endocytosis.
 36.
Osmosis is a type of
a.
 active transport.
c.
 simple diffusion.
b.
 passive transport.
d.
 endocytosis.
 37.
How does water pass through the cell membrane?
a.
 directly through the lipid bilayer
b.
 through a water ion pump
c.
 through water carrier proteins
d.
 through channel proteins just for water
 38.
Which of the following statements about an isotonic solution and a cell is correct?
a.
 The solution has the same solute concentration that the cytoplasm does.
b.
 The solution has a higher solute concentration than the cytoplasm does.
c.
 A cell in the solution will lose water.
d.
 A cell in the solution will gain water.
 39.
Unlike passive transport, active transport
a.
 requires energy.
b.
 moves substances down their concentration gradient.
c.
 does not involve carrier proteins.
d.
 moves water across the cell membrane.
 40.
Both active transport and facilitated diffusion involve
a.
 ATP.
b.
 movement against a concentration gradient.
c.
 carrier proteins.
d.
 channel proteins.
 41.
Which of the following is a form of active transport?
a.
 osmosis
c.
 facilitated diffusion
b.
 simple diffusion
d.
 sodium-potassium pump
 42.
The sodium-potassium pump
a.
 is a carrier protein.
c.
 is located in the cytoplasm of a cell.
b.
 uses passive transport.
d.
 transports sugar molecules.
 43.
The sodium-potassium pump usually pumps
a.
 potassium ions out of the cell.
b.
 sodium ions into the cell.
c.
 potassium ions into the cell.
d.
 only potassium ions and sugar molecules.
 44.
How many potassium ions does the sodium-potassium pump move into a cell if it moves six sodium ions out of the cell?
a.
 two
c.
 six
b.
 four
d.
 eight
 45.
Proteins and polysaccharides that are too large to move into a cell through diffusion or active transport move in by
a.
 exocytosis.
c.
 the sodium-potassium pump.
b.
 endocytosis.
d.
 channel proteins.
 46.
Molecules that are too large to be moved across a cell membrane can be removed from the cell by
a.
 diffusion.
c.
 endocytosis.
b.
 exocytosis.
d.
 osmosis.
 47.
Removing materials from a cell in vesicles is called
a.
 osmosis.
c.
 exocytosis.
b.
 diffusion.
d.
 endocytosis.
 48.
Which of the following descriptions of hormones is correct?
a.
 signal molecules distributed throughout the body
b.
 signal molecules that affect all cells in the body
c.
 target molecules that communicate through direct contact
d.
 target molecules that originate outside the body
nar003-1.jpg
 49.
Refer to the illustration above. What happens when the structure labeled A binds to the structure labeled B?
a.
 Information is sent into the cell.
c.
 The cell begins to swell.
b.
 Proteins enter the cell.
d.
 Ions enter the cell.
 50.
Refer to the illustration above. The structure labeled B in the diagram is an example of a(n)
a.
 channel protein.
c.
 receptor protein.
b.
 signal molecule.
d.
 ion pump.
 51.
Signal molecules bind to
a.
 carbohydrates.
c.
 receptor proteins.
b.
 marker proteins.
d.
 transport proteins.
 52.
Which of the following transmit information into a cell by binding to signal molecules?
a.
 channel proteins
c.
 marker proteins
b.
 receptor proteins
d.
 signal proteins
 53.
What change takes place in the cell membrane if a signal molecule causes a transport protein to open?
a.
 permeability change
c.
 formation of a second messenger
b.
 activation of an enzyme
d.
 change in chemical reactions
 

Completion
Complete each statement.
 54.
One way cells maintain homeostasis is by controlling the movement of substances across the cell ____________________.
 55.
A(n) ____________________ is a specialized lipid made of a phosphate head and two fatty acid tails.
 56.
The phosphate head of a phospholipid is attracted to water because it is ____________________.
 57.
The fatty acid tails of a phospholipid are repelled by water because they are ____________________.
 58.
The phospholipids form a barrier through which only small, ____________________ substances can pass.
 59.
Ions and most polar molecules are repelled by the ____________________ interior of the lipid bilayer.
 60.
____________________ – ____________________ markers are attached to the cell surface and have sugars attached to their protein.
 61.
Proteins that aid in moving substances into and out of cells are called ____________________ proteins.
 62.
____________________ are proteins in the cell membrane that help with important biochemical reactions inside the cell.
 63.
____________________ proteins enable a cell to sense its surroundings by binding to certain substances outside the cell.
 64.
To reach equilibrium, substances always flow from an area of high concentration to an area of ____________________ concentration.
 65.
When one area has a higher concentration than another area does, a concentration ____________________ exists.
 66.
Substances diffuse through a cell membrane either through the lipid bilayer or through ____________________ proteins.
 67.
Oxygen and carbon dioxide pass through the lipid bilayer by ____________________ diffusion.
 68.
Diffusion of ions through ion channels is a form of ____________________ transport.
 69.
Carrier proteins change ____________________ to transport substances to the interior of cells.
 70.
A cell does not expend ____________________ when diffusion takes place.
 71.
The diffusion of ____________________ through cell membranes is called osmosis.
 72.
When the concentration of free water molecules is higher outside a cell than inside the cell, water will diffuse ____________________ the cell.
 73.
If a cell is placed in a(n) ____________________ solution, water will flow out of the cell.
 74.
If a cell is placed in a(n) ____________________ solution, water will flow into the cell.
 75.
If a cell is placed in a(n) ____________________ solution, water flows into the cell at a rate that is equal to the rate at which water flows out of the cell.
 76.
Active transport requires the use of ____________________ by a cell.
 77.
The ____________________ – ____________________ pump transports ions against their concentration gradients.
 78.
The sodium-potassium pump uses energy supplied by ____________________.
 79.
The sodium-potassium pump prevents the accumulation of ____________________ ions inside the cell.
 80.
The movement of a substance into a cell by a vesicle is called ____________________.
nar004-1.jpg
A
B
 81.
Refer to the illustration above. The process shown in figure B is called ____________________.
 82.
Refer to the illustration above. The process shown in figure A is called ____________________.
 83.
A signaling cell produces a signal that is detected by a ____________________ cell.
 84.
Light is an environmental ____________________ for the flowering of some plants.
 85.
In the cell membrane, proteins that bind to specific signal molecules and respond are called ____________________ proteins.
 86.
Receptor proteins can change the ____________________ of the cell membrane.
 87.
Receptor proteins may act as ____________________, triggering certain chemical reactions inside the cell.
 

Short Answer
 88.
In addition to its function as a gatekeeper, what are three other functions of the cell membrane?
 89.
What makes up the lipid bilayer?
 90.
In the lipid bilayer, what causes one layer of polar heads to face the cell’s cytoplasm and the other layer of heads to face the cell’s surroundings?
 91.
What characteristic of membrane proteins causes them to be held in the cell membrane?
 92.
What are four types of proteins in cell membranes?
 93.
What exists across a cell membrane if equilibrium is not reached?
 94.
What is the difference between how a molecule crosses the cell membrane in simple diffusion and in facilitated diffusion?
 95.
What are two types of transport proteins?
 96.
Why are some water molecules not free to move across the cell membrane?
 97.
Explain why osmosis is a form of facilitated diffusion.
 98.
What specific carrier protein moves sodium ions out of a cell and potassium ions into a cell?
 99.
What is the function of the cell membrane during endocytosis?
 100.
What are hormones, how are they distributed, and what cells do they affect?
 101.
What happens to a receptor protein once it binds to a signal molecule?
 102.
How can the cell’s response to a signal cause a permeability change?
 

Problem
 103.

A biologist conducts an experiment designed to determine whether a particular type of molecule is transported into cells by simple diffusion, facilitated diffusion, or active transport. He collects the following information:

1. The molecule is very small.
2. The molecule is polar.
3. The molecule can accumulate inside a cell, even when its concentration inside the cell initially is higher than it is outside the cell.
4. Cells use up more energy when the molecule is present in the environment around the cells than when it is not present.

The biologist concludes that the molecule moves across cell membranes by facilitated diffusion. Do you agree with his conclusion? Why or why not?
Paramecia are unicellular protists. They have a number of characteristics also found in animals, such needing to ingest food in order to obtain energy and being surrounded by a cell membrane but not by a rigid cell wall. Paramecia have organelles found in animal cells, including a nucleus, mitochondria, ribosomes, and cilia. In addition, they have star-shaped organelles, called contractile vacuoles, that expel excess water. The illustration below depicts a paramecium.

nar005-1.jpg
 104.

Refer to the illustration above. The data presented in the table below were obtained in an experiment in which paramecia were placed in salt water with different concentrations of salt and the rate at which their contractile vacuoles contracted to pump out excess water was recorded.

Salt Concentration
Number of contractile vacuole contractions/minute
Very high
2
High
8
Medium
15
Low
22
Very low
30

 

a. How can you explain the observed relationship between salt concentration and rate of contractile vacuole contraction?
b. If something happened to a paramecium that caused its contractile vacuoles to stop contracting, what would you expect to happen? Would this result occur more quickly if the paramecium was in water with a high salt concentration or in water with a low salt concentration? Why?

 

Essay
 105.
Distinguish between facilitated diffusion and active transport.
 106.
Compare the processes of sodium ions moving through the cell membrane by an ion channel and by an ion pump.
 107.
Why do dissolved particles on one side of a membrane result in the diffusion of water across the membrane?
 108.
Why is it dangerous for humans to drink seawater?
nar004-1.jpg
A
B
 109.
Refer to the illustration above. Identify and explain the processes taking place in figure A and figure B.
 110.
Describe three ways in which the binding of a signal molecule to a receptor protein can change the functioning of a cell.

 
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Chapter 2 Study Guide

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Chapter 2 study guide
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
Atoms are composed of
a.
 protons with a positive charge.
b.
 neutrons with no charge.
c.
 electrons with a negative charge.
d.
 All of the above
 2.
The smallest particle of carbon that can retain the chemical properties of carbon is
a.
 a carbon molecule.
b.
 a carbon macromolecule.
c.
 a carbon atom.
d.
 the nucleus of a carbon atom.
 3.
A substance that is composed of only one type of atom is called a(n)
a.
 nucleus.
c.
 element.
b.
 cell.
d.
 molecule.
 4.
All matter in the universe is composed of
a.
 cells.
c.
 atoms.
b.
 molecules.
d.
 carbon.
 5.
The electrons of an atom
a.
 are found in the nucleus along with the protons.
b.
 orbit the nucleus in various energy levels.
c.
 have a positive charge.
d.
 are attracted to the positive charge of neutrons.
 6.
Atoms that have gained energy
a.
 have protons and neutrons that move farther apart.
b.
 lose neutrons from the nucleus.
c.
 have electrons that move to higher energy levels.
d.
 absorb electrons into the nucleus.
 7.
Which of the following states of matter contain(s) particles that are tightly linked together in a definite shape?
a.
 solid
c.
 gas
b.
 liquid
d.
 solid and liquid
 8.
Because carbon has four electrons in its outer energy level,
a.
 it can form bonds with carbon atoms only.
b.
 these atoms are naturally chemically stable.
c.
 it can react with up to four other atoms to form covalent bonds.
d.
 it cannot react with anything other than organic molecules.
 9.
The bond formed when two atoms share a pair of electrons is called a
a.
 hydrogen bond.
c.
 covalent bond.
b.
 nonpolar bond.
d.
 water bond.
 10.
Sharing of electrons between atoms of two or more elements
a.
 results in the formation of an ion.
b.
 results in the formation of a compound.
c.
 results in the formation of noble gases.
d.
 results in destabilization of the atoms involved.
 11.
An atom that has gained or lost electrons is called a(n)
a.
 molecule.
c.
 ion.
b.
 nucleon.
d.
 element.
 12.
Which of the following statements most accurately describes the difference between an ionic bond and a covalent bond?
a.
 Atoms held together by ionic bonds separate when placed in water, while atoms held together by covalent bonds do not separate in water.
b.
 Ionic bonds hold together atoms of two different types, while covalent bonds hold together atoms of the same type.
c.
 Electrons are exchanged between atoms held together by an ionic bond, but they are shared between atoms held together by a covalent bond.
d.
 Ionic bonds form between atoms that carry opposite charges, while covalent bonds form between uncharged atoms.
nar001-1.jpg
 13.
Refer to the graph above. Reaction 1 in the graph
a.
 is an energy-storing reaction.
b.
 requires a greater activation energy than reaction 2.
c.
 may use the same initial reactant condition needed to form product Y.
d.
 All of the above
 14.
Refer to the graph above. Reaction 3 in the graph
a.
 probably occurred in the presence of a catalyst.
b.
 requires a greater activation energy than reaction 2.
c.
 is the same as reaction 1, but faster.
d.
 takes longer than reaction 2.
 15.
Refer to the graph above. Which of these statements regarding the graph is true?
a.
 Reaction 2 occurs faster than reaction 3 because reaction 2 requires more energy than reaction 3.
b.
 The difference in the graphs shown for reaction 2 and reaction 3 is due to a difference in the activation energy needed for these reactions.
c.
 Reactant X contains more energy at the beginning of the reaction than product Z has after the reaction.
d.
 All of the above
 16.
Changing the course or pathway of a chemical reaction so that it requires less activation energy
a.
 is a violation of the laws of nature.
b.
 requires higher temperatures than those found within cells.
c.
 occurs only when reactants are quickly added to the reaction mixture.
d.
 is accomplished by the action of catalysts on reactants.
 17.
Enzymes
a.
 are able to heat up molecules so that they can react.
b.
 provide CO2 for chemical reactions.
c.
 are biological catalysts.
d.
 absorb excess heat so that reactions occur at low temperatures.
 18.
A single organism may contain
a.
 thousands of different enzymes, each one specific to a different chemical reaction.
b.
 one enzyme that plays a role in thousands of different chemical reactions.
c.
 approximately 100 kinds of enzymes, each one specific to a different chemical reaction.
d.
 one enzyme that is specific to photosynthesis and one enzyme that is specific to cellular respiration.
 19.
When a molecule gains an electron, it has been
a.
 oxidized.
c.
 digested.
b.
 reduced.
d.
 inactivated.
 20.
Oxidation-reduction reactions are important in organisms because they
a.
 allow the passage of energy from molecule to molecule.
b.
 prevent nuclear reactions from occurring.
c.
 allow the creation and destruction of energy.
d.
 None of the above; oxidation-reduction reactions do not occur in living organisms.
 21.
The concentration of a solution is
a.
 the number of particles of a substance in a solvent.
b.
 the amount of a solvent that is dissolved in a fixed amount of a solution.
c.
 the amount of a solute that is dissolved in a fixed amount of a solution.
d.
 the ratio of solute to solvent in a solution.
 22.
A neutral solution has an equal number of
a.
 hydrogen and hydronium ions.
b.
 hydroxide and hydronium ions.
c.
 hydrogen and hydroxide ions.
d.
 oxygen and hydrogen ions.
 23.
The terms base and alkaline refer to solutions that
a.
 contain dissolved sodium hydroxide.
b.
 contain more hydronium ions than hydroxide ions.
c.
 contain more hydroxide ions than hydronium ions.
d.
 contain more hydroxide ions than hydrogen ions.
 24.
A solution with a pH of 11 is
a.
 acidic.
c.
 neutral.
b.
 alkaline.
d.
 a buffer.
 25.
Acidic solutions have a pH that is
a.
 less than 7.
c.
 a negative number.
b.
 between 0 and 14.
d.
 more than 7.
 26.
Buffers
a.
 are of relatively little importance in living things.
b.
 are formed when a large number of hydroxide ions are released in a solution.
c.
 are formed when a large number of hydronium ions are released in a solution.
d.
 tend to prevent great fluctuations in pH.
 27.
Atoms become more stable when they form compounds because
a.
 they always lose electrons when they form compounds.
b.
 their outer orbitals become filled when they form compounds.
c.
 they always gain electrons when they form compounds.
d.
 their nucleus loses extra protons when they form compounds.
 28.
A water molecule is polar because its hydrogen and oxygen atoms
a.
 both lose electrons.
b.
 become ions.
c.
 both gain electrons.
d.
 do not share the electrons equally.
 29.
Polar molecules such as water have
a.
 no negative or positive poles.
b.
 both negative and positive poles.
c.
 only a negative pole.
d.
 only a positive pole.
 30.
A molecule that has a partial positive charge on one side and a partial negative charge on the other side is called a
a.
 nonpolar molecule.
c.
 charged molecule.
b.
 polar molecule.
d.
 bipolar molecule.
 31.
Water is a polar molecule because
a.
 it contains two hydrogen atoms for each oxygen atom.
b.
 it has a charge.
c.
 different parts of the molecule have slightly different charges.
d.
 it does not have a charge.
 32.
Water molecules break up other polar substances
a.
 such as salts.
b.
 because of the uneven charge distribution that exists in water molecules.
c.
 thus freeing ions in these substances for use by the body.
d.
 All of the above
 33.
Which of the following characteristics of water is not a result of hydrogen bonding?
a.
 adhesive strength
b.
 capillarity
c.
 cohesive strength
d.
 All of the above are a result of hydrogen bonding.
 

Completion
Complete each statement.
 34.
Substances that are changed when they become involved in chemical reactions are called ____________________, while the new substances that are formed are called ____________________.
 35.
The energy needed to break existing chemical bonds during the initiation of a chemical reaction is called ____________________.
 36.
Chemical reactions in the body can be speeded up by adding a(n) ____________________, which lowers the amount of activation energy required to start the reaction.
 37.
The loss of electrons from a molecule is called ____________________, while the gain of electrons by a molecule is called ____________________.
 38.
A substance that dissolves in another is called a(n) ____________________.
 39.
____________________ is the most common solvent in cells.
 40.
____________________ and ____________________ ions form when water dissociates.
 41.
An acidic solution is one that has more ____________________ than ____________________ ions.
 42.
A solution with a pH of 3 has ____________________ times more hydronium ions than a solution with a pH of 6.
 43.
Buffers are important because body fluids must be maintained within a relatively narrow range of ____________________.
 44.
Water is very effective at dissolving other polar substances because of its ____________________.
 45.
Breaking of ____________________ bonds is the first thing that happens when water is heated, which means that it takes a great deal of thermal energy to raise the temperature of water.
 

Problem
 46.

pr046-1.jpg

Refer to the illustration above. The graph depicts the relative energy levels of the products and reactants for the following chemical reaction: A + B C + D. Write your answers to the following in the spaces below.

a.      Which substances, A, B, C, and/or D, are present at point 1 on the graph?
b.      Which substances, A, B, C, and/or D, are present at point 3 on the graph?
c.      Why is point 2 at a higher energy level than point 1?
d.      Why is point 3 at a lower energy level than point 1?
e.      Draw a dashed line on the graph indicating how the energy level of this reaction over time would be different if the enzyme that catalyzes the reaction were not present.
 

Essay
 47.
Plant growers often use sprinkler irrigation to protect crops they are growing from frost damage. The water that lands on the leaves turns to ice. How does this protect the plants from frost damage? Write your answer in the space below.
 48.
Define enzyme, and describe how an enzyme can function in speeding up a chemical reaction within a cell. Write your answer in the space below.
 49.
How does water’s polar nature affect its ability to dissolve different substances? Write your answer in the space below.
 50.
Explain the relationship between hydrogen bonding and the observation that a full sealed bottle of water breaks when it freezes. Write your answer in the space below.

 
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