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Annelids and Mollusks Study Guide

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Annelids and Mollusks Quiz

 

  

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 
 1.
Which of the following is not a characteristic of at least some mollusks?
a.
 a pseudocoelomate body plan
b.
 bilateral symmetry
c.
 a mantle
d.
 an open circulatory system
 
 2.
Which of the following has a true coelom?
a.
 flatworm
c.
 rotifer
b.
 roundworm
d.
 mollusk
 
 3.
The evolution of a coelom was significant because
a.
 more food could be stored within it.
b.
 more wastes could be stored before excretion.
c.
 it enabled development of more complex organ systems.
d.
 it eliminated the need for a circulatory system.
 
 4.
mollusks : a mantle ::
a.
 pseudocoelomate animals : true body cavities
b.
 roundworms : single-opening digestive tract
c.
 roundworms : coelom
d.
 mollusks : a coelom
 
 5.
The cilia of a trochophore
a.
 allow attachment to the ocean bottom.
b.
 create currents for drawing in food.
c.
 cover the entire larval body.
d.
 are necessary for reproduction.
 
 6.
Trochophores
a.
 occur in some mollusks’ life cycles.
b.
 possess a belt of cilia around their bodies.
c.
 occur in some annelids’ life cycles.
d.
 All of the above
 
 7.
A characteristic structure found in many mollusks is the radula, which is involved in
a.
 jet propulsion.
c.
 eating.
b.
 opening and closing of the shell.
d.
 reproduction.
 
 8.
Which of the following is a correct pairing?
a.
 phylum Platyhelminthes—hydra
b.
 phylum Nematoda—planaria
c.
 phylum Mollusca—octopus
d.
 phylum Annelida—roundworm
 
 9.
All of the animal phyla that evolved after the mollusks
a.
 are vertebrates.
c.
 have a coelom.
b.
 are prokaryotes.
d.
 lack mesoderm.
 
 10.
All of the following are classes of the phylum Mollusca except
a.
 bivalves.
c.
 gastropods.
b.
 cephalopods.
d.
 pseudopods.
 
 11.
Which of the following mollusks have a closed circulatory system?
a.
 snails
c.
 slugs
b.
 cephalopods
d.
 gastropods
 
 12.

mc012-1.jpg

Refer to the illustration above. Which two organisms have mantles?

a.
 1 and 3
c.
 1 and 4
b.
 2 and 3
d.
 2 and 4
 
 13.
Jet propulsion is the usual means of locomotion in water for
a.
 octopuses.
c.
 squids.
b.
 gastropods.
d.
 bivalves.
 
   
 
nar001-1.jpg
 
 14.
Refer to the illustration above. This organism is a
a.
 bivalve.
c.
 trochophore.
b.
 cephalopod.
d.
 gastropod.
 
 15.
Refer to the illustration above. Movement of this organism is dependent upon structure
a.
 1.
c.
 3.
b.
 2.
d.
 None of the above
 
 16.
Shells of mollusks
a.
 may consist of one or more pieces.
b.
 provide protection.
c.
 allow for the attachment of muscles.
d.
 All of the above
 
 17.
Adductor muscles are responsible for
a.
 moving the valves of bivalves.
b.
 extending the feet of mollusks.
c.
 pumping the hearts of mollusks.
d.
 fanning the gills of aquatic mollusks.
 
 18.
In an open circulatory system,
a.
 water is drawn into the mantle cavity to provide oxygen to body tissues.
b.
 lungs branch into small tubules to provide oxygen to tissues.
c.
 wastes are eliminated directly to the environment from the tissues.
d.
 blood is released directly into spaces in the body tissues.
 
 19.
Twisting of the visceral mass of gastropods is called
a.
 extension.
c.
 torsion.
b.
 inversion.
d.
 conversion.
 
 20.
Among the various species of gastropods, respiration may take place
a.
 with gills.
b.
 through the skin.
c.
 within the mantle cavity.
d.
 All of the above
 
 21.
All of the cephalopods
a.
 have eight tentacles.
b.
 are predators.
c.
 possess protective shells.
d.
 are filter feeders.
 
 22.
Jet propulsion in a squid is the result of
a.
 rapid closing of the organism’s shell.
b.
 strong contractions of the tentacles.
c.
 high-pressure discharge of fluid from the organism’s mouth.
d.
 the pumping of water through the siphon.
 
 23.
The only cephalopod that has retained its external shell is the
a.
 cuttlefish.
c.
 octopus.
b.
 chambered nautilus.
d.
 squid.
 
 24.
Segmented worms are known as
a.
 nematodes.
c.
 planarians.
b.
 annelids.
d.
 arthropods.
 
 25.
Each segment of an annelid
a.
 is capable of reproduction.
b.
 has a well-developed brain that allows the annelid to learn simple tasks.
c.
 has a pseudocoelom.
d.
 may contain some organ systems that duplicate systems in other segments.
 
 26.
An example of segmentation in humans is the
a.
 digestive system.
c.
 vertebral column.
b.
 skin.
d.
 brain.
 
 27.
The most significant evolutionary advancement of annelids over mollusks is believed to be
a.
 the ability to burrow.
c.
 segmentation.
b.
 the existence of a true coelom.
d.
 cephalization.
 
 28.

mc028-1.jpg

Refer to the illustration above. Which two organisms have segmented body plans?

a.
 3 and 4
c.
 1 and 4
b.
 2 and 4
d.
 2 and 3
 
 29.
true coelom : mollusks and annelids ::
a.
 tentacle : annelids
c.
 valve : annelids
b.
 siphon : annelids
d.
 segmentation : annelids
 
 30.
Coordinated movements of an earthworm’s body segments are possible because of the
a.
 development of an advanced brain.
b.
 ventral nerve cord and ganglia that carry impulses to the muscles.
c.
 presence of a true coelom in the earthworm’s body.
d.
 existence of a complete digestive system.
 
 31.
earthworm movement : circular muscles and setae ::
a.
 earthworm digestion : circular muscles and setae
b.
 earthworm digestion : seminal receptacles
c.
 earthworm reproduction : pharynx
d.
 earthworm respiration : skin
 
 32.
Small tubules that collect wastes from the coelom of annelids and discharge the wastes from the body are called
a.
 nephridia.
c.
 bivalves.
b.
 radulae.
d.
 spicules.
 
 33.
The digestive tube of the earthworm is divided into three regions. Which of the following is not among these regions?
a.
 crop
c.
 radula
b.
 intestine
d.
 gizzard
 
 34.
Which of the following is (are) not part of an earthworm’s body?
a.
 a heart
c.
 nephridia
b.
 gills
d.
 a typhlosole
 
 35.
The clitellum of an earthworm
a.
 contains the heart.
b.
 is associated with reproduction.
c.
 acts as a primitive respiratory system.
d.
 is necessary for movement.
 
 36.
Earthworms are considered to be beneficial to the environment because
a.
 they help release nutrients into the soil.
b.
 they aerate the soil as they move through it.
c.
 they break up the soil in which they live.
d.
 All of the above
 
 37.
squid motion : siphon ::
a.
 annelid motion : siphon
b.
 annelid breathing : nephridia
c.
 earthworm circulation : closed circulatory system
d.
 annelid motion : tentacles
 
 38.
The body of the water leech
a.
 has suckers on the front and back.
c.
 is segmented.
b.
 has no parapodia.
d.
 All of the above
 
 39.
Leeches
a.
 use suckers to aid in movement.
c.
 are segmented.
b.
 may be parasitic.
d.
 All of the above
 
 40.
leeches : blood ::
a.
 earthworms : small animals
b.
 earthworms : blood
c.
 marine polychaetes : small animals
d.
 marine polychaetes : blood
 
  

Completion
Complete each statement.
 
   41.
The ____________________ larva is a characteristic of some mollusks and annelids.
 
 

 
   42.
Constant beating of ____________________ in the mantle cavity of a clam causes a continuous stream of water to pass over the gills.
 
 

 
   43.
A tonguelike scraping organ used by some mollusks in feeding is called the ____________________.
 
 

 
   44.
An organ known as the ____________________ is an abrasive, tonguelike structure found in some mollusks.
 
 

 
   45.
A snail can pull its head into its mantle cavity because the cavity has moved to the anterior of the animal during a twisting process called ____________________ that occurs during development.
 
 

 
   46.
Water is drawn into the body of a clam through tubes called ____________________.
 
 

 
   47.
A bivalve’s shells close when the pair of ____________________ contract.
 
 

 
   48.
Structures in earthworms that function as simple kidneys are called ____________________.
 
 

 
   49.
The only living cephalopod that has retained its external shell is the _________________________.
 
 

 
   50.
Snails and slugs belong to the class of mollusks called ____________________.
 
 

 
   51.
Earthworms belong to the phylum ____________________.
 
 

 
   52.

co052-1.jpg

Refer to the illustration above. Structure X is the ventral ____________________ cord.

 
 

 
   53.
In anterior segments of annelids, several ganglia are fused to form the ____________________, which is the brain of these organisms.
 
 

 
   54.
An earthworm’s ____________________ produces a tube made of mucus and chitin that contains the eggs and sperm and allows development of an earthworm’s offspring.
 
 

 
   55.
Bristles that exist along the sides of an annelid are called ____________________.
 
 

 
   56.
Some leeches are ____________________; they feed on the blood of other animals.
 
 

 
   57.
The ____________________ are annelids that have many setae and parapodia, generally live in marine environments, and have antennae.
 
 

 

 

 
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Mollusks

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Mollusks

 

 

True/False
Indicate whether the sentence or statement is true or false.
1.
Mollusks must eat constantly because the functioning of their nephridia causes the disposal of useful molecules as well as of waste products.
2.
Unlike arthropods, mollusks are unsegmented; instead, they are divided into three regions.
3.
Mollusks have four distinct body parts: a foot, a head, a visceral mass, and a tail.
4.
In terrestrial snails, the mantle cavity functions as a simple lung.
5.
Most bivalves have separate sexes, but some are hermaphroditic.
6.
Due to the presence of a shell, all gastropods are capable of living on land for at least a portion of their lives.
7.
Since cephalopods have tentacles, they have no need for a radula.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
8.
All of the following are characteristics of mollusks except that they have
a.
a pseudocoelomate body plan.
c.
a complete digestive tract.
b.
bilateral symmetry.
d.
an open circulatory system.
9.
The cilia of a trochophore larva
a.
allow attachment to the ocean bottom.
b.
create currents for drawing in food.
c.
cover the entire larval body.
d.
are necessary for reproduction.
10.
Trochophore larvae
a.
are found in molluscan life cycles.
b.
possess a belt of cilia around their bodies.
c.
occur in annelid life cycles.
d.
All of the above
11.
A characteristic structure found in many mollusks is the radula, which is involved in
a.
jet propulsion.
c.
eating.
b.
opening and closing of the shells.
d.
reproduction.
12.
All of the following are classes of the phylum Mollusca except
a.
bivalves.
c.
gastropods.
b.
cephalopods.
d.
pseudopods.
13.
The only mollusks that have a closed circulatory system are
a.
bivalves.
c.
chitons.
b.
cephalopods.
d.
gastropods.
      mollusks_files/i0160000.jpg
14.
Refer to the illustration above. Which two organisms in the diagrams possess mantles?
a.
Organisms “A” and “C”
c.
Organisms “A” and “D”
b.
Organisms “B” and “C”
d.
Organisms “B” and “D”
15.
“Jet propulsion” is the usual means of locomotion in water for
a.
arthropods.
c.
cephalopods.
b.
echinoderms.
d.
annelids.
      mollusks_files/i0190000.jpg
16.
Refer to the illustration above. The organism shown in this diagram is a
a.
bivalve.
c.
chiton.
b.
cephalopod.
d.
gastropod.
17.
Refer to the illustration above. This organism possesses a(n)
a.
simple lung.
c.
internal beak.
b.
closed circulatory system.
d.
open circulatory system.
18.
Refer to the illustration above. Movement of this organism is dependent upon the structure labeled
a.
“1.”
c.
“3.”
b.
“2.”
d.
None of the above
19.
Shells of mollusks
a.
may consist of one or more pieces.
c.
allow for the attachment of muscles.
b.
provide protection.
d.
All of the above
20.
Adductor muscles are responsible for
a.
moving the valves of bivalves.
c.
pumping the hearts of mollusks.
b.
extending the feet of mollusks.
d.
fanning the gills of aquatic mollusks.

 
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Moss & Fern Quiz

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Moss and Fern

 

 

True/False
Indicate whether the sentence or statement is true or false.
1.
Land plants have a complex life cycle that involves an alternation of generations between a haploid gametophyte and a diploid sporophyte.
2.
The sporophyte of a nonvascular plant is larger and lives longer than the gametophyte.
3.
The life cycle of nonvascular plants involves alternation of generations.
4.
Mosses, liverworts, and hornworts all are generally found in moist habitats.
5.
Nonvascular plants have true leaves but lack true stems and roots.
6.
Mosses and ferns no longer require the presence of a film of water for reproduction.
7.
Ferns need water to reproduce because their sperm must swim to eggs.
8.
Mosses are called pioneer plants because they can promote the development of new communities in barren areas that have been burned or destroyed by humans.
9.
Sphagnum moss is used in potting and gardening soils because of its ability to encourage water drainage.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
10.
The ancestors of today’s land plants were probably
a.
brown algae.
c.
green algae.
b.
red algae.
d.
lichens.
11.
The challenges faced by early land plants included
a.
conserving water.
b.
reproducing on land.
c.
absorbing minerals from the rocky surface.
d.
All of the above
12.
The diploid form in a plant’s life cycle is called the
a.
sporophyte.
c.
parental generation.
b.
gametophyte.
d.
alternate generation.
13.
The haploid form in a plant’s life cycle is called the
a.
sporophyte.
c.
parental generation.
b.
gametophyte.
d.
alternate generation.
14.
Which of the following is not a bryophyte?
a.
moss
c.
hornwort
b.
liverwort
d.
fern
15.
Which of the following is not characteristic of all nonvascular plants?
a.
They produce seeds.
b.
They have an alternation of generations lifestyle.
c.
They produce spores.
d.
They require water for sexual reproduction.
16.
The water-retaining ability of sphagnum moss makes it ideal for
a.
using in garden-soil mixes.
b.
use in packing bulbs and flowers for shipping.
c.
use in houseplant soils.
d.
All of the above
17.
Similarities shared by monocots and primitive dicots suggest that
a.
monocots and dicots evolved independently.
b.
monocots were on Earth long before dicots.
c.
monocots evolved from dicots.
d.
dicots evolved from monocots.

 
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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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