Category: Cellular Processes

Nucleic Acids

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Nucleic Acids

 

 

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.
It has been discovered that the genetic material is protein. _________________________
 2.
Hershey and Chase were the first two scientists to prove that genetic material is composed of proteins. _________________________
 3.
The five-carbon sugar in DNA nucleotides is called ribose. _________________________
 4.
After years of research, the structure of the DNA molecule is now known to be a double helix. _________________________
 5.
Franklin’s X-ray diffraction images suggested that the DNA molecule resembled a tightly coiled spring, a shape called a helix. _________________________
 6.
In all living things, DNA replication must occur after cell division. _________________________
 7.
Before a DNA molecule can replicate itself, it must coil up. _________________________
 8.
Helicases unwind the double helix of DNA by breaking the nitrogen bonds that link the base pairs. _________________________
 9.
Errors in nucleotide sequence that occur during replication cannot be corrected. _________________________
 10.
RNA molecules contain the five-carbon sugar ribose. _________________________
 11.
During transcription, the information on a DNA molecule is “rewritten” into an mRNA molecule. _________________________
 12.
When a tRNA anticodon binds to an mRNA codon, the amino acid detaches from the tRNA molecule and bonds to the end of a growing protein chain. _________________________
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 13.
Griffith’s transformation experiments
a.
 changed proteins into DNA.
b.
 caused harmless bacteria to become deadly.
c.
 resulted in DNA molecules becoming proteins.
d.
 were designed to show the effect of heat on bacteria.
 14.
Griffith’s experiments showed that
a.
 dead bacteria could be brought back to life.
b.
 harmful bacteria were hardier than harmless bacteria.
c.
 heat caused the harmful and harmless varieties of bacteria to fuse.
d.
 genetic material could be transferred between dead bacteria and living bacteria.
 15.
Avery’s experiments showed that transformation
a.
 is prevented by protein-destroying enzymes.
b.
 is prevented by DNA-destroying enzymes.
c.
 causes protein to become DNA.
d.
 is caused by a protein.
 16.
Avery and his research team concluded that
a.
 RNA was the genetic material.
b.
 protein bases were the genetic material.
c.
 DNA and RNA were found in the human nucleus.
d.
 DNA was responsible for transformation.
 17.
Using radioactive tracers to determine the interactions of bacteriophages and their host bacteria, Hershey and Chase demonstrated without question that
a.
 genes are composed of protein molecules.
b.
 DNA and proteins are actually the same molecules located in different parts of cells.
c.
 bacteria inject their DNA into the cytoplasm of bacteriophages.
d.
 DNA is the molecule that stores genetic information in cells.
 18.
All of the following are true of the viruses Hershey and Chase used in their study except
a.
 they consisted of DNA surrounded by a protein coat.
b.
 they injected their DNA into cells.
c.
 they destroyed the DNA of the infected bacteria.
d.
 they caused infected bacteria to make many new viruses.
 19.
The scientist who worked with Martha Chase to prove that genetic material is composed of DNA was
a.
 Alfred Hershey.
c.
 Francis Crick.
b.
 Oswald Avery.
d.
 Rosalind Franklin.
 20.
Molecules of DNA are composed of long chains of
a.
 amino acids.
c.
 monosaccharides.
b.
 fatty acids.
d.
 nucleotides.
 21.
Which of the following is not part of a molecule of DNA?
a.
 deoxyribose
c.
 phosphate
b.
 nitrogen base
d.
 ribose
 22.
A nucleotide consists of
a.
 a sugar, a protein, and adenine.
b.
 a sugar, an amino acid, and starch.
c.
 a sugar, a phosphate group, and a nitrogen base.
d.
 a starch, a phosphate group, and a nitrogen base.
 23.
The part of the molecule for which DNA is named is the
a.
 phosphate group.
c.
 nitrogen base.
b.
 sugar.
d.
 hydrogen bonds.
 24.
Purines and pyrimidines are
a.
 nitrogen bases found in amino acids.
b.
 able to replace phosphate groups from defective DNA.
c.
 names of specific types of DNA molecules.
d.
 classification groups of nitrogen bases.
 25.
Of the four nitrogen bases in DNA, which two are purines and which two are pyrimidines?
a.
 purines: adenine, thymine; pyrimidines: uracil, cytosine
b.
 purines: adenine, thymine; pyrimidines: guanine, cytosine
c.
 purines: adenine, guanine; pyrimidines: thymine, cytosine
d.
 purines: uracil, thymine; pyrimidines: guanine, cytosine
 26.
The amount of guanine in an organism always equals the amount of
a.
 protein.
c.
 adenine.
b.
 thymine.
d.
 cytosine.
 27.
adenine : thymine ::
a.
 protein : DNA
c.
 guanine : cytosine
b.
 Watson : Crick
d.
 guanine : thymine
 28.
Watson and Crick built models that demonstrated that
a.
 DNA and RNA have the same structure.
b.
 DNA is made of two strands that twist into a double helix.
c.
 guanine forms hydrogen bonds with adenine.
d.
 thymine forms hydrogen bonds with cytosine.
 29.
The scientists credited with establishing the structure of DNA are
a.
 Avery and Chargaff.
c.
 Mendel and Griffith.
b.
 Hershey and Chase.
d.
 Watson and Crick.
 30.
X-ray diffraction photographs by Wilkins and Franklin suggested that
a.
 DNA and RNA are the same molecules.
b.
 DNA is composed of either purines or pyrimidines, but not both.
c.
 DNA molecules are arranged as a tightly coiled helix.
d.
 DNA and proteins have the same basic structure.
 31.
During DNA replication, a complementary strand of DNA is made from each original DNA strand. Thus, if a portion of the original strand is CCTAGCT, then the new strand will be
a.
 TTGCATG.
c.
 CCTAGCT.
b.
 AAGTATC.
d.
 GGATCGA.
 32.
Which of the following is not true about DNA replication?
a.
 It must occur before a cell can divide.
b.
 Two complementary strands are duplicated.
c.
 The double strand unwinds and unzips while it is being duplicated.
d.
 The new DNA molecule has two newly-made strands.
 33.
The attachment of nucleotides to form a complementary strand of DNA during replication
a.
 is accomplished by DNA polymerase.
b.
 is accomplished only in the presence of tRNA.
c.
 prevents separation of complementary strands of RNA.
d.
 is the responsibility of the proofreading enzymes.
 34.
The enzymes responsible for adding nucleotides to the exposed DNA bases during replication are
a.
 replicases.
c.
 helicases.
b.
 DNA polymerases.
d.
 template enzymes.
 35.
The enzymes that unwind DNA during replication are called
a.
 double helixes.
c.
 forks.
b.
 DNA helicases.
d.
 phages.
 36.
All of the following are true about DNA replication in prokaryotic cells except
a.
 replication begins at many sites along the DNA.
b.
 replication begins at one site along the DNA loop.
c.
 replication occurs in two opposite directions.
d.
 there are two replication forks.
 37.
Transcription, which is a stage of gene expression, is the process by which genetic information encoded in DNA is transferred to a(n)
a.
 RNA molecule.
c.
 uracil molecule.
b.
 DNA molecule.
d.
 tRNA molecule.
 38.
RNA differs from DNA in that RNA
a.
 is double-stranded.
c.
 contains the nitrogen base uracil.
b.
 contains deoxyribose.
d.
 does not contain adenine.
 39.
RNA is chemically similar to DNA except that the sugar in RNA has an additional
a.
 oxygen atom.
c.
 nitrogen base.
b.
 phosphate group.
d.
 carbon atom.
 40.
In RNA molecules, adenine is complementary to
a.
 cytosine.
c.
 thymine.
b.
 guanine.
d.
 uracil.
 41.
Each of the following is a type of RNA except
a.
 carrier RNA.
c.
 ribosomal RNA.
b.
 messenger RNA.
d.
 transfer RNA.
 42.
During transcription,
a.
 proteins are synthesized.
c.
 RNA is produced.
b.
 DNA is replicated.
d.
 translation occurs.
 43.
During transcription, the genetic information for making a protein is “rewritten” as a molecule of
a.
 messenger RNA.
c.
 transfer RNA.
b.
 ribosomal RNA.
d.
 translation RNA.
 44.
Transcription begins when RNA polymerase
a.
 attaches to a ribosome.
b.
 unwinds a strand of DNA.
c.
 binds to a strand of RNA.
d.
 attaches to the promoter sequence of a gene.
mRNA: CUCAAGUGCUUC

nar001-1.jpg
 45.
Refer to the illustration above. What is the portion of the protein molecule coded for by a piece of mRNA with the sequence CUCAAGUGCUUC?
a.
 Ser—Tyr—Arg—Gly
c.
 Leu—Lys—Cys—Phe
b.
 Val—Asp—Pro—His
d.
 Pro—Glu—Leu—Val
 46.
Refer to the illustration above. The anticodons for the codons in the mRNA with the sequence CUCAAGUGCUUC are
a.
 GAG—UUC—ACG—AAG.
c.
 CUC—GAA—CGU—CUU.
b.
 GAG—TTC—ACG—AAG.
d.
 CUU—CGU—GAA—CUC.
 47.
Refer to the illustration above. Which of the following would represent the strand of DNA from which the mRNA strand CUCAAGUGCUUC was made?
a.
 CUCAAGUGCUUC
c.
 GAGTTCACGAAG
b.
 GAGUUCACGAAG
d.
 AGACCTGTAGGA
mRNA codons amino acid
UAU, UAC tyrosine
CCU, CCC, CCA, CCG proline
GAU, GAC aspartic acid
AUU, AUC, AUA isoleucine
UGU, UGC cysteine
 48.
Refer to the illustration above. Suppose that you are given a protein containing the following sequence of amino acids: tyrosine, proline, aspartic acid, isoleucine, and cysteine. Use the portion of the genetic code given to determine which of the following contains a DNA sequence that codes for this amino acid sequence.
a.
 AUGGGUCUAUAUACG
c.
 GCAAACTCGCGCGTA
b.
 ATGGGTCTATATACG
d.
 ATAGGGCTTTAAACA
 49.
The function of rRNA is to
a.
 synthesize DNA.
c.
 form ribosomes.
b.
 synthesize mRNA.
d.
 transfer amino acids to ribosomes.
 50.
At the very beginning of translation, the first tRNA molecule
a.
 binds to the mRNA’s anticodon.
b.
 attaches directly to the DNA codon.
c.
 connects an amino acid to its anticodon.
d.
 binds to the mRNA’s start codon.
 51.
Transfer RNA
a.
 carries an amino acid to its correct codon.
b.
 synthesizes amino acids as they are needed.
c.
 produces codons to match the correct anticodons.
d.
 converts DNA into mRNA.
 52.
Which of the following does not affect the final outcome of gene expression?
a.
 the environment of the cells
b.
 the number of amino acids in the protein being produced
c.
 the presence of other cells
d.
 the timing of gene expression
 

Completion
Complete each statement.
 53.
Griffith’s experiment showed that live bacteria without capsules acquired the ability to make capsules from dead bacteria with capsules in a process Griffith called ____________________.
 54.
Avery’s prevention of transformation using DNA-destroying enzymes provided evidence that ____________________ molecules function as the hereditary material.
 55.
A DNA subunit composed of a phosphate group, a five-carbon sugar, and a nitrogen-containing base is called a(n) ____________________.
 56.
The name of the five-carbon sugar that makes up a part of the backbone of molecules of DNA is ____________________.
 57.
Due to the strict pairing of nitrogen bases in DNA molecules, the two strands are said to be ____________________ to each other.
 58.
Watson and Crick determined that DNA molecules have the shape of a(n) ____________________ ____________________.
 59.
Chargaff’s observations established the ____________________ rules, which describe the specific pairing between bases on DNA strands.
 60.
Watson and Crick used the X-ray diffraction photographs of ____________________ and ____________________ to build their model of DNA.
 61.
The process by which DNA copies itself is called ____________________.
 62.
Enzymes called ____________________ are responsible for unwinding the DNA double helix by breaking the hydrogen bonds that hold the complementary strands together.
 63.
Errors in nucleotide sequencing are corrected by enzymes called ____________________.
 64.
Transcription and translation are stages in the process of ____________________.
 65.
The second stage of gene expression is called ____________________.
 66.
The nitrogen-containing base that is found only in RNA is ____________________.
 67.
The enzyme responsible for making mRNA is called ____________________.
 68.
Messenger RNA is produced during the process of ____________________.
 69.
The sequence of three nucleotides that code for specific amino acids or stop signals in the synthesis of protein is called a(n) ____________________.
 70.
During translation, amino acids are brought to the ribosomes by molecules of ____________________.
 71.
Nucleotide sequences of tRNA that are complementary to codons on mRNA are called ____________________.
 72.
The information contained in a molecule of messenger RNA is used to make protein during the process of ____________________.

 
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Chapter 5 – Cell Transport Study Guide

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Chapter 5 Cell Transport studyguide

 

 

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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Cell Reproduction

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Cell Reproduction

 

 

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.
A gene is a segment of DNA that directs the production of RNA and protein. _________________________
 2.
The information needed by a cell to direct its activities and to determine its characteristics is contained in molecules of protein. _________________________
 3.
After the replication of a cell’s DNA, there are twice as many centromeres as there are chromatids. _________________________
 4.
Cells that seldom divide spend most of their time in interphase. _________________________
 5.
After mitosis and interphase, each new cell has a complete set of the parent cell’s chromosomes. _________________________
 6.
In animal cells, cytokinesis results when a cell plate forms across the cell to divide the cytoplasm. _________________________
 7.
Plant cells separate their cytoplasm during cytokinesis when protein threads pinch the cell in half. _________________________
 8.
The cell cycle has four checkpoints that act to inhibit uncontrolled cell division. _________________________
 9.
Offspring formed by asexual reproduction look exactly like their parent. _________________________
 10.
In budding, new individuals develop from pieces of the original individual. _________________________
 11.
Some eukaryotes reproduce asexually, and some produce sexually. _________________________
 12.
In asexual reproduction, two parents each pass genetic material to their offspring. _________________________
 13.
Asexual reproduction provides for genetic diversity, the raw material for evolution. _________________________
 14.
Genetic diversity is the raw material for evolution. _________________________
 15.
Genes on chromosomes are the units of inheritance. _________________________
 16.
Each human somatic cell contains two copies of each chromosome for a total of 23 chromosomes. _________________________
 17.
Gametes are diploid so that when fertilization occurs, the resulting zygote will have the characteristic number of chromosomes for that species. _________________________
 18.
While paired together during the second division of meiosis, two chromosomes may exchange segments of DNA. _________________________
 19.
Crossing-over is the exchange of corresponding portions of chromatids between homologous chromosomes. _________________________
 20.
Random fertilization refers to the fact that homologous chromosomes are distributed randomly during meiosis. _________________________
 21.
The process by which sperm are produced in male animals is called spermatogenesis. _________________________
 22.
During the diploid life cycle, all of the cells are diploid. _________________________
 23.
During the haploid life cycle, the zygote is the only diploid cell. _________________________
 24.
In the life cycle of a plant, the gametophyte is the haploid phase that produces gametes by mitosis. _________________________
 25.
A spore gives rise to a multicellular individual without joining with another cell. _________________________
 26.
Moss plants have haploid life cycles. ______________________________
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 27.
Which of the following is not a reason cells divide?
a.
 The cell gets too big to process and transport nutrients.
b.
 New cells are needed for growth.
c.
 DNA cannot be copied quickly enough in large cells.
d.
 Surface area-to-volume ratio becomes too large.
 28.
The chromosome of a bacterium
a.
 is wrapped around proteins.
b.
 has a circular shape.
c.
 occurs in multiple pairs within the cell.
d.
 is found within the nucleus.
 29.
The region of a chromosome where two sister chromatids are held together is called a
a.
 spindle.
c.
 nucleosome.
b.
 centromere.
d.
 centriole.
 30.
Chromatids are
a.
 dense patches within the nucleus.
b.
 bacterial chromosomes.
c.
 joined strands of duplicated genetic material.
d.
 prokaryotic nuclei.
 31.
When a chromosome condenses,
a.
 a histone wraps around chromatin.
b.
 beads form on the DNA double helix.
c.
 its centromere splits.
d.
 looped domains coil into a structure.
 32.
In order to fit within a cell, DNA becomes more compact by
a.
 breaking apart into separate genes.
b.
 extending to form very long, thin molecules.
c.
 wrapping tightly around histones.
d.
 being enzymatically changed into a protein.
 33.
In a bacterium, cell division takes place when
a.
 its nucleus divides.
b.
 the cell splits into two cells, one of which receives all of the DNA.
c.
 the DNA is copied, a new cell wall forms between the DNA copies, and the cell splits into two cells.
d.
 spindle fibers form.
 34.
The phase of the cell cycle that occupies most of an average cell’s life is
a.
 G1.
c.
 G2.
b.
 mitosis.
d.
 S.
 35.
What occurs after cytokinesis is completed?
a.
 The cell organizes its microtubules.
c.
 The cell enters G1.
b.
 The cell begins to replicate its DNA.
d.
 The cell enters G2.
 36.
Which of the following shows the correct sequence of the cell cycle?
a.
 cytokinesis ® mitosis ® G1 ® S ® G2
b.
 S ® G1 ® G2 ® mitosis ® cytokinesis
c.
 G1 ® S ® G2 ® mitosis ® cytokinesis
d.
 mitosis ® G1 ® S® G2 ® cytokinesis
 37.
Cells that are not dividing remain in the
a.
 mitosis phase.
c.
 first gap phase.
b.
 synthesis phase.
d.
 second gap phase.
 38.
The synthesis (S) phase is characterized by
a.
 DNA replication.
b.
 cell division.
c.
 replication of mitochondria and other organelles.
d.
 the division of cytoplasm.
 39.
5 steps : the cell cycle ::
a.
 6 steps : prophase
c.
 3 steps : meiosis
b.
 9 steps : cytokinesis
d.
 4 steps : mitosis
 40.
The first three phases of the cell cycle are collectively known as
a.
 a gap.
c.
 mitosis.
b.
 telophase.
d.
 interphase.
 41.
cell growth : G1 ::
a.
 mitosis : cytokinesis
b.
 mitosis : meiosis
c.
 mitochondria replication : synthesis phase
d.
 DNA copying : synthesis phase
 42.
metaphase : prophase ::
a.
 G1 : mitosis
c.
 mitosis : cytokinesis
b.
 G2 : S
d.
 S : mitosis
 43.
Mitosis is the process by which
a.
 microtubules are assembled.
b.
 cytoplasm is divided.
c.
 the nucleus is divided into two nuclei.
d.
 the cell rests.
 44.
A spindle fiber is a specialized form of
a.
 microtubule.
c.
 centriole.
b.
 centrosome.
d.
 chromosome.
 45.
The phase of mitosis that is characterized by the arrangement of all chromosomes along the equator of the cell is called
a.
 telophase.
c.
 anaphase.
b.
 metaphase.
d.
 prophase.
nar001-1.jpg
 46.
Refer to the illustration above. The cell in diagram 1 is in
a.
 metaphase.
c.
 anaphase.
b.
 telophase.
d.
 prophase.
 47.
Refer to the illustration above. Mitosis begins with the stage shown in diagram
a.
 1.
c.
 3.
b.
 2.
d.
 4.
 48.
Refer to the illustration above. The cell shown in diagram 5 is in
a.
 metaphase.
c.
 anaphase.
b.
 telophase.
d.
 prophase.
nar002-1.jpg
 49.
Refer to the illustration above. Which of the following correctly indicates the order in which these events occur?
a.
 A, B, C, D
c.
 B, A, C, D
b.
 C, B, A, D
d.
 A, C, B, D
 50.
Refer to the illustration above. During which stage do the centromeres divide?
a.
 A
c.
 C
b.
 B
d.
 D
 51.
As a result of mitosis, each of the two new cells produced from the parent cell during cytokinesis
a.
 receives a few chromosomes from the parent cell.
b.
 receives an exact copy of all the chromosomes present in the parent cell.
c.
 donates a chromosome to the parent cell.
d.
 receives exactly half the chromosomes from the parent cell.
 52.
Cytokinesis in plant cells involves the formation of
a.
 a belt of protein threads.
c.
 spindle fibers.
b.
 a cell plate.
d.
 centrioles.
 53.
Which of the following statements is true?
a.
 Prokaryotes divide by mitosis.
b.
 Eukaryotes have circular chromosomes.
c.
 Animal cells form new cell walls when they divide.
d.
 Plant cells and animal cells have different strategies for cytokinesis.
 54.
In eukaryotes, the cell cycle is controlled by
a.
 proteins.
c.
 lipids.
b.
 carbohydrates.
d.
 fats.
 55.
At the G2 checkpoint, DNA replication is checked by
a.
 receptor proteins.
c.
 repair enzymes.
b.
 electron transport chains.
d.
 cell-surface markers.
 56.
The cell cycle is monitored as each cell passes through
a.
 the S phase.
c.
 the interphase checkpoint.
b.
 checkpoints.
d.
 cytokinesis.
 57.
Normal cells become cancer cells when
a.
 regulation of cell growth and division occurs.
b.
 cells respond to control mechanisms.
c.
 cells pass through G1.
d.
 cells do not respond to checkpoints.
 58.
Which of the following is not a type of asexual reproduction?
a.
 budding
c.
 binary fission
b.
 fragmentation
d.
 fertilization
 59.
Hydras reproduce by
a.
 budding.
c.
 binary fission.
b.
 fragmentation.
d.
 parthenogenesis.
 60.
Budding is an example of
a.
 endosymbiosis.
c.
 meiosis.
b.
 asexual reproduction.
d.
 sexual reproduction.
 61.
The simplest and most primitive method of reproduction is
a.
 sexual.
c.
 haploid.
b.
 diploid.
d.
 asexual.
 62.
Binary fission
a.
 occurs when two cells collide with each other.
b.
 produces excess energy.
c.
 creates new species.
d.
 is the process by which bacteria reproduce.
 63.
The process of producing offspring is called reproduction and can be
a.
 eukaryotic or prokaryotic.
c.
 zygotic or gametic.
b.
 asexual or sexual.
d.
 haploid or diploid
 64.
Sexual reproduction includes
a.
 budding.
c.
 binary fission.
b.
 fragmentation.
d.
 fertilization
 65.
Normal human males develop from fertilized eggs containing which of the following sex chromosome combinations?
a.
 XY
c.
 XO
b.
 XX
d.
 OO
 66.
Homologous chromosomes are pairs of chromosomes containing genes that code for
a.
 different traits.
c.
 DNA.
b.
 the same traits.
d.
 sex.
 67.
In humans, gametes contain
a.
 22 autosomes and 1 sex chromosome.
b.
 1 autosome and 22 sex chromosomes.
c.
 45 autosomes and 1 sex chromosome.
d.
 1 autosome and 45 sex chromosomes.
 68.
In humans, the male determines the sex of the child because males have
a.
 two X chromosomes.
c.
 two Y chromosomes.
b.
 one X and one Y chromosome.
d.
 46 chromosomes.
 69.
The X and Y chromosomes are called
a.
 extra chromosomes.
c.
 sex chromosomes.
b.
 homologous chromosomes.
d.
 autosomes.
 70.
female : XX ::
a.
 female : gametes
c.
 male : YY
b.
 female : eggs
d.
 male : XY
 71.
How many chromosomes are in the body cells of an organism that has a haploid number of 8?
a.
 4
c.
 12
b.
 8
d.
 16
 72.
The diploid number of chromosomes in a human skin cell is 46. The number of chromosomes found in a human egg cell is
a.
 46.
c.
 23.
b.
 92.
d.
 12.5.
 73.
diploid : somatic cell :: haploid :
a.
 body cell
c.
 gamete
b.
 chromosome
d.
 zygote
 74.
A haploid cell is one that
a.
 has two homologues of each chromosome.
b.
 is designated by the symbol 2n.
c.
 has chromosomes found in pairs.
d.
 has one set of chromosomes.
nar003-1.jpg
 75.
Refer to the illustration above. The process shown is
a.
 mitosis.
c.
 meiosis.
b.
 chromosomal mutation.
d.
 dominance.
 76.
Separation of homologues occurs during
a.
 mitosis.
c.
 meiosis II.
b.
 meiosis I.
d.
 fertilization.
 77.
When crossing-over takes place, chromosomes
a.
 mutate in the first division.
b.
 produce new genes.
c.
 decrease in number.
d.
 exchange corresponding segments of DNA.

Using the information you have learned about cell reproduction, infer answers to the questions below about a cell with a diploid number of 4 chromosomes. Select from among the diagrams below, labeled A, B, C, D, and E, to answer the questions.

nar004-1.jpg
 78.
Which of the diagrams above depicts a cell at the end of meiosis I?
a.
 B
c.
 D
b.
 C
d.
 E
 79.
Which of the diagrams above depicts a cell at the end of meiosis II?
a.
 A
c.
 C
b.
 B
d.
 D
 80.
Which of the diagrams above depicts a cell at the beginning of mitosis?
a.
 B
c.
 D
b.
 C
d.
 E
 81.
Which of the diagrams above depicts a cell at the end of mitosis?
a.
 A
c.
 C
b.
 B
d.
 D
 82.
The difference between anaphase of mitosis and anaphase I of meiosis is that
a.
 the chromosomes line up at the equator in anaphase I.
b.
 centromeres do not exist in anaphase I.
c.
 chromatids do not separate at the centromere in anaphase I.
d.
 crossing-over occurs only in anaphase of mitosis.
 83.
The exchange of segments of DNA between the members of a pair of chromosomes
a.
 ensures that variations within a species never occur.
b.
 acts as a source of variations within a species.
c.
 always produces genetic disorders.
d.
 is called genetic crossing.
 84.
Crossing-over occurs
a.
 during prophase II.
c.
 during prophase I.
b.
 during fertilization.
d.
 at the centromere.
 85.
Which of the following does not provide new genetic combinations?
a.
 random fertilization
c.
 independent assortment
b.
 cytokinesis
d.
 crossing-over
 86.
During cytokinesis in the female, what divides unequally?
a.
 the sperm cell
c.
 the cytoplasm
b.
 the ovary
d.
 the DNA
 87.
The more common name for an ovum is a(n)
a.
 egg.
c.
 nutrient.
b.
 hormone.
d.
 polar body.
 88.
To create new haploid cells during the haploid life cycle, the zygote undergoes
a.
 mitosis.
c.
 fusion.
b.
 fertilization.
d.
 meiosis.
 89.
Which of the following is not a type of sexual life cycle?
a.
 alternation of generations
c.
 diploid
b.
 haploid
d.
 parthenogenesis
 90.
In alternation of generations, a diploid spore-forming cell gives rise to four
a.
 zygotes.
c.
 haploid spores.
b.
 sperm cells.
d.
 diploid spores.
 91.
During alternation of generations, cells reproduce by
a.
 meiosis only.
c.
 both meiosis and mitosis.
b.
 mitosis only.
d.
 binary fission.
 

Completion
Complete each statement.
 92.
Growth occurs through cell enlargement and cell ____________________.
 93.
The DNA in eukaryotic cells is packaged into structures called ____________________.
 94.
A duplicated chromosome consists of two identical ____________________, which are held together at the centromere.
 95.
The sequence of events that occurs in a cell from one cell division to the next is called the ____________________.
 96.
Collectively, the time spent in G1 + S + G2 is called ____________________.
 97.
A cell’s DNA is copied during the ____________________ phase.
 98.
Cells that are not dividing remain in the ____________________ phase.
 99.
Spindle fibers are made of hollow tubes of protein called ____________________.
 100.
The spindle is assembled by the ____________________.
 101.
In most eukaryotic cells, ____________________ takes place after the nucleus divides.
 102.
In plant cells, a(n) ____________________ forms in the center of the cell during cytokinesis.
 103.
Normal cell growth and cell division are regulated by ____________________.
 104.
The cell cycle is controlled in eukaryotes at three principal ____________________.
 105.
Loss of control and regulation of the ____________________ can result in the development of cancer.
 106.
The separation of a parent into two or more individuals of about equal size is called ____________________.
 107.
Binary fission is the process by which ____________________ split asexually into two identical organisms.
 108.
Only ____________________ cells can produce gametes.
 109.
Somatic cells containing two sets of 23 chromosomes each are always ____________________.
 110.
After a new nuclear membrane forms during telophase I of meiosis, the ____________________ divides, resulting in two cells.
 111.
The process called ____________________ guarantees that the number of chromosomes in gametes is half the number of chromosomes in body cells.
 112.
Prophase I of meiosis is different from prophase of mitosis in that every chromosome pairs with its ____________________.
 113.
A reciprocal exchange of corresponding segments of DNA is called ____________________ – ____________________.
 114.
The four haploid cells formed in the male at the end of meiosis II develop tails and are called ____________________.
 115.
The diploid number of chromosomes is re-established through ____________________.
 116.
In a haploid life cycle, ____________________ results in the first cell of a multicellular haploid organism.

 
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Chapter 5 Homeostasis and Transport RETEST

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Chapter 5 Homeostasis and Transport RETEST
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
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 on the outside of a membrane.
d.
 becomes imbalanced on both sides of a membrane.
 2.
Diffusion takes place
a.
 only through a lipid bilayer membrane.
b.
 from an area of low concentration to an area of high concentration.
c.
 only in liquids.
d.
 from an area of high concentration to an area of low concentration.
            Concentration of Water and Solutes in Four Adjacent Cells

nar001-1.jpg
 3.
Refer to the illustration above. Which cell is most likely to lose both water molecules and solute molecules as the system approaches equilibrium?
a.
 cell “A”
c.
 cell “C”
b.
 cell “B”
d.
 cell “D”
 4.
Refer to the illustration above. In this system, solute molecules in cell “B” are most likely to
a.
 remain in cell “B.”
c.
 diffuse into cell “A.”
b.
 adhere to cell “B’s” membrane.
d.
 diffuse into cell “D”
 5.
Refer to the illustration above. In this system, water molecules are most likely to diffuse in which direction?
a.
 from “A” to “B”
c.
 from “D” to “C”
b.
 from “B” to “D”
d.
 from “C” to “A”
 6.
The dispersal of ink in a beaker of water is an example of
a.
 diffusion.
c.
 active transport.
b.
 osmosis.
d.
 endocytosis.
 7.
heavy rains : flooding ::
a.
 osmosis : proton pumping
b.
 high solute concentration : isotonic solution
c.
 active transport : ATP
d.
 concentration difference : osmosis
 8.
Sugar molecules can enter cells through the process of
a.
 exocytosis.
c.
 osmosis.
b.
 facilitated diffusion.
d.
 ion pumps.
 9.
Channels utilizing facilitated diffusion
a.
 work in two directions.
b.
 require an electrical signal to function.
c.
 Both a and b
d.
 None of the above
 10.
Which of the following is not characteristic of facilitated diffusion?
a.
 It requires a carrier protein.
b.
 It moves substances against a concentration gradient.
c.
 It requires no energy input.
d.
 It involves a change in the shape of its carrier.
 11.
Which of the following is true of ions and their transport across cell membranes?
a.
 The “gates” for ion channels are always open.
b.
 Ions are very small and thus can cross cell membranes readily.
c.
 Electrical or chemical signals may control the movement of ions across cell membranes.
d.
 Because they are charged particles, the movement of ions across cell membranes requires energy input.
 12.
Which of the following does not expend energy?
a.
 diffusion
c.
 active transport
b.
 chemiosmosis
d.
 a sodium-potassium pump
 13.
Which of the following enters a cell by active transport?
a.
 glucose
c.
 sodium ion
b.
 water
d.
 potassium ion
 14.
The process by which water passes into or out of a cell is called
a.
 solubility.
c.
 selective transport.
b.
 osmosis.
d.
 endocytosis.
nar002-1.jpg
 15.
Refer to the illustration above. The process shown is called
a.
 osmosis.
c.
 active transport.
b.
 facilitated diffusion.
d.
 diffusion.
 16.
The sodium-potassium pump usually pumps
a.
 potassium out of the cell.
b.
 sodium into the cell.
c.
 potassium into the cell.
d.
 only a potassium and sugar molecule together.
 17.
proton pump : protons ::
a.
 ATP : protons
c.
 sodium-potassium pump : ATP
b.
 channel : protons
d.
 sodium-potassium pump : sodium
 18.
Ridding the cell of material by discharging it from sacs at the cell surface is called
a.
 chemiosmosis.
c.
 exocytosis.
b.
 exorcism.
d.
 endocytosis.
 19.
Molecules that are too large to be moved across a cell membrane can be removed from the cell by
a.
 diffusion.
c.
 lipid carriers.
b.
 exocytosis.
d.
 osmosis.
 20.
Molecules that are too large to be moved through the membrane can be transported into the cell by
a.
 osmosis.
c.
 lipid carriers.
b.
 endocytosis.
d.
 diffusion.
 21.
endocytosis : exocytosis ::
a.
 phagocytosis : bacteria
c.
 cold : hot
b.
 secrete : exocytosis
d.
 white blood cell : bacteria

 
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