CH 11 12 16 & 26 STUDY QUESTIONS

CHAPTER 11

DNA and Its Role in Heredity

TEST FILE QUESTIONSFill in the Blank

1. The X-ray crystallographs of the English chemist _______ were essential for the discovery of the structure of the DNA molecule.

Answer: Rosalind Franklin

2. Since the DNA molecule is continuous, nucleotide pair after nucleotide pair, their information must lie in the _______ sequence of the nitrogenous bases.

Answer: linear

3. Arthur Kornberg showed that DNA could replicate in the test tube if it contained intact DNA for a template, a mixture of the four precursors (the four nucleoside triphosphates), and _______.

Answer: DNA polymerase

4. The material that changed R strain pneumococcus into the virulent S strain was originally referred to as the _______.

Answer: transforming principle

5. The basic units of DNA and RNA molecules are the _______.

Answer: nucleotides (or nitrogenous bases)

6. The experiments of Meselson and Stahl established the _______ of DNA.

Answer: semiconservative replication

7. The nitrogenous bases classified as purines are _______ and _______.

Answer: adenine; guanine

8. The nitrogenous bases classified as pyrimidines are_______ and _______.

Answer: cytosine; thymine

9. Using Meselson and Stahl’s experimental system for studying the mode of replication of DNA, researchers analyze the genetic information from a life-form from Mars. After the first round of replication, they see two distinct bands in the cesium chloride gradient. This finding is consistent with _______ replication.

Answer: conservative

10. The enzyme that replicates the lagging strand is _______.

Answer: DNA polymerase III

11. In prokaryotes the enzyme that replicates the leading strand is called _______.

Answer: DNA polymerase III

12. The region of DNA where replication begins is the_______.

Answer: origin of replication

13. The fragments of RNA and DNA found on the lagging strand of DNA prior to RNA removal and ligation are called _______.

Answer: Okazaki fragments

14. The purines take up (more/less) _______ space in the center of a DNA molecule than the pyrimidines do.

Answer: more

15. In a sequencing reaction, the shortest sequences are those that end closer to the (5 /3 )_______ end than to the ′ ′(5 /3 ) _______ end of the synthesized molecule.′ ′

Answer: 5′; 3′′

16. The _______ function of the DNA polymerase reduces the number of mistakes by the square of the frequency of the error rate.

Answer: proofreading

17. The repetitive sequences at the end of many chromosomes are called _______.

Answer: telomeres.

18. An enzyme that catalyzes the addition of any lost telomere sequences is _______.

Answer: telomerase

TEXTBOOK SELF QUIZ QUESTIONS

1. Griffith’s studies of Streptococcus pneumoniae

a. showed that DNA is the genetic material of bacteria.

b. showed that DNA is the genetic material of bacteriophage.

c. demonstrated the phenomenon of bacterial transformation.

d. proved that prokaryotes reproduce sexually.

e. proved that protein is not the genetic material.

2. In the Hershey–Chase experiment,

a. DNA from parent bacteriophages appeared in progeny bacteriophages.

b. most of the phage DNA never entered the bacteria.

c. more than three-fourths of the phage protein appeared in progeny phages.

d. DNA was labeled with radioactive sulfur.

e. DNA formed the coat of the bacteriophages.

3. Which statement about complementary base pairing is not true?

a. It plays a role in DNA replication.

b. In DNA, T pairs with A.

c. Purines pair with purines, and pyrimidines pair with pyrimidines.

d. In DNA, C pairs with G.

e. The base pairs are of equal length.

4. In semiconservative replication of DNA,

a. the original double helix remains intact and a new double helix forms.

b. the strands of the double helix separate and act as templates for new strands.

c. polymerization is catalyzed by RNA polymerase.

d. polymerization is catalyzed by a double helical enzyme.

e. DNA is synthesized from amino acids.

5. Which of the following does not occur during DNA replication?

a. Unwinding of the parent double helix

b. Formation of short pieces that are connected by DNA ligase

c. Complementary base pairing

d. Use of a primer

e. Polymerization in the 3 -to-5 direction′ ′

6. The primer used for DNA replication

a. is a short strand of RNA added to the 3 end.′

b. is present only once on the leading strand.

c. remains on the DNA after replication.

d. ensures that there will be a free 5 end to which nucleotides can be added.′

e. is added to only one of the two template strands.

7. One strand of DNA has the sequence 5 —ATTCCG—3 . The complementary strand for this is′ ′

a. 5 —TAAGGC—3′ ′

b. 5 —ATTCCG—3′ ′

c. 5 —ACCTTA—3′ ′

d. 5 —CGGAAT—3′ ′

e. 5 —GCCTTA—3′ ′

8. The role of DNA ligase in DNA replication is to

a. add more nucleotides to the growing strand one at a time.

b. open up the two DNA strands to expose template strands.

c. ligate base to sugar to phosphate in a nucleotide.

d. bond Okazaki fragments to one another.

e. remove incorrectly paired bases.

9. The polymerase chain reaction

a. is a method for sequencing DNA.

b. is used to transcribe specific genes.

c. amplifies specific DNA sequences.

d. does not require DNA replication primers.

e. uses a DNA polymerase that denatures at 55oC.

10. The following events occur in excision repair of DNA. What is their proper order?

(1) Base-paired DNA is made complementary to the template.

(2) Damaged bases are recognized.

(3) DNA ligase seals the new strand to existing DNA.

(4) Part of a single strand is excised.

a. 1234

b. 2134

c. 2413

d. 3421

e. 4231

Answers

1. c

2. a

3. c

4. b

5. e

6. b

7. d

8. d

9. c

10. c

ONLINE QUIZ QUESTIONS

1.To show that DNA in cell extracts was responsible for genetic transformation in pneumococcus, important corroborating evidence was that

a.enzymes that destroyed proteins also destroyed transforming activity.

b.enzymes that destroyed DNA also destroyed transforming activity.

c.enzymes that destroyed polysaccharides also destroyed transforming activity.

d.boiling destroyed transforming activity.

e.enzymes that destroyed RNA also destroyed transforming activity.

Answer: b

2.In the Meselson-Stahl experiment, the researchers

a.devised a simple way to distinguish new DNA strands from old DNA strands.

b.used “light” isotopes of nitrogen as a key ingredient in their experiment.

c.grew four cultures of the bacterium E.Coli for a few generations.

d.combined and centrifuged the four cultures and four separate DNA bands formed.

e.began with three hypotheses—three models of DNA replication—and was designed so that the results could differentiate between them.

Answer: e

3.Which statement about the double helical structure of DNA is false?

a.The genetic material stores an organism’s genetic information.

b.The genetic material is susceptible to mutation.

c.The genetic material is precisely replicated in the cell division cycle.

d.The genetic material is expressed as the genotype.

e.The genetic material can be replicated by complementary base pairing.

Answer: d

4.In dispersive replication of DNA,

a.the original double helix remains intact and a new double helix forms.

b.the strands of the double helix separate and act as templates for new strands.

c.the original DNA molecule serves as a template for assembling two molecules containing old and new parts.

d.polymerization is catalyzed by a double helical enzyme.

e.DNA is synthesized from amino acids.

Answer: c

5.Which of the following statements does not summarize the molecular architecture of the DNA molecule?

a.The sugar-phosphate “backbones” of the polynucleotide chains coil within the inside of the helix

b.It is a double-stranded helix.

c.It has a uniform diameter.

d.It is right-handed (that is, it twists to the right, as do the threads on most screws).

e.It is antiparalleled (the two strands run in opposite directions).

Answer: a

6.Which of the following is not required for DNA replication?

a.A short strand of RNA to act as a primer

b.DNA to act as a template

c.Single-strand binding proteins

d.RNA polymerase

e.DNA polymerase

Answer: d

7.The 3 end of a DNA strand is defined as the place where′

a.the phosphate group is not bound to another nucleotide.

b.primase synthesizes an RNA primer and DNA polymerase binds to begin replication.

c.RNA polymerase binds to begin replication.

d.DNA polymerase directs the production of Okazaki fragments.

e.three A residues are present.

Answer: b

8.The leading strand and lagging strand in DNA replication differ in that only on the lagging strand

a.DNA is replicated as short fragments.

b.RNA primer is present.

c.DNA ligase is not needed.

d.replication is slower.

e.replication proceeds in a 5 to 3 direction.′ ′

Answer: a

9.Which statement about DNA polymerase is false?

a.DNA polymerases are much larger than their substrates.

b.DNA polymerase can start a DNA strand from scratch.

c.DNA polymerase requires a primer for replication.

d.In a cell that has several DNA polymerases, only one can be responsible for chromosomal DNA replication.

e.DNA polymerase catalyzes the synthesis of new DNA strands.

Answer: b

10.Which of the following statements about mismatch repair of DNA is correct?

a.The DNA is scanned for any base-pairing mismatches after methyl groups are added to guanines.

b.Errors in replication made by DNA polymerase are corrected on the unmethylated strand.

c.All abnormal bases are always removed.

d.Repairs from damage caused by high-energy radiation are made.

e.Mismatch repair occurs as each strand of DNA is being replicated.

Answer: b

11.The following events occur in excision repair of DNA. What is their proper order?

1 Base-paired DNA is made complementary to the template.

2 Damaged bases are recognized.

3 DNA ligase seals the new strand to existing DNA.

4 Part of a single strand is excised.

a. 1234

b. 2134

c. 2413

d. 3421

e. 4231

Answer: c

12.In DNA polymerization,

a. DNA polymerases add deoxyribonucleotides only to the 3 end of a growing strand.′

b. the 3 end of the primer contains a free 3 -hydroxyl group.′ ′

c. the strand grows from the 3 end to the 5 end.′ ′

d. a and b.

e. b and c.

Answer: d

13.Which of the following statements concerning DNA replication is true?

a. Helicases initiate replication by winding the two strands together.

b. DNA polymerase I catalyzes the elongation of the new DNA strands in prokaryotes.

c. The leading strand elongates from its 3 to 5 end.′ ′

d. The lagging strand is synthesized as Okazaki fragments.

e. Primase binds to RNA and synthesizes a DNA primer.

Answer: d

14.Eukaryotic chromosomes

a. contain linear molecules of double-stranded DNA.

b. have uncoiled DNA.

c. have multiple origins of replication.

d. a and c

e. have two replication forks that move in the same direction.

Answer: d

15.Eukaryotes only have one origin of replication.

a. true

b. false

Answer: b

16.The appropriate adjective to describe DNA replication is

a. nondisruptive.

b. semiconservative.

c. progressive.

d. natural.

e. lytic.

Answer: b

Chapter 12 TEST FILE QUESTIONS

Fill in the Blank

1. Prototrophs (“original eaters”) grow on minimal media, whereas _______ (“increased eaters”) require specific additional nutrients.

Answer: auxotrophs

2. The basic units of DNA and RNA molecules are the _______.

Answer: nucleotides

3. RNA differs from DNA in base composition in that it contains _______ instead of thymine.

Answer: uracil

4. The strand of DNA that is transcribed into RNA is the _______ strand.

Answer: template

5. The part of a protein that determines whether translation will continue in the cytosol or at the endoplasmic reticulum is the _______ sequence.

Answer: signal

6. The excess of codons (64) over amino acids (20) indicates that the genetic code is _______.

Answer: redundant

7. An mRNA molecule with several ribosomes attached at the same time is called a(n) _______.

Answer: polysome

8. Small ribosomal subunits are dispersed into smaller components when placed into a detergent solution. Upon removal of the detergent, the components interact to create new intact subunits by a process called _______.

Answer: self-assembly

9. A mutation that causes a change in the nitrogenous base sequence of a DNA molecule but no change in the amino acid sequence it codes for is called a(n) _______ mutation.

Answer: silent

10. The fact that some tRNA molecules do not have to pair exactly is called _______.

Answer: wobble

11. The portion of the tRNA molecule that complementary base-pairs with the mRNA is called the _______.

Answer: anticodon

12. The lethal toxin that is produced by the castor bean plant and that blocks protein synthesis is _______.

Answer: ricin

13. The one-gene, one-enzyme hypothesis resulted from the work of ______.

Answer: Beadle and Tatum

14. The synthesis of DNA from RNA is called _______.

Answer: reverse transcription

15. A tRNA that has bonded to an amino acid is referred to as _______ tRNA.

Answer: charged

ONLINE QUIZ QUESTIONS

1.Which of the following is not a characteristic of RNA?

a.RNA contains uracil as a base.

b.The sugar molecule in RNA is ribose.

c.RNA can base-pair with DNA.

d.RNA consists of a single polynucleotide strand.

e.RNA contains more bases than DNA.

Answer: e

2.A neurospora mutant cannot grow unless the amino acid, leucine, is added to its growth medium. This strain is

a.dependent on leucine for energy.

b.mutated in genes coding for the synthesis of all 20 amino acids.

c.inhibited by leucine.

d.wild-type for the synthesis of all amino acids except for leucine.

e.mutated for the synthesis of all amino acids except for leucine.

Answer: d

3.Which of the following was hypothesized to have traveled through the nucleus to the cytoplasm, where it served as a template for the synthesis of proteins?

a.tRNA

b.mRNA

c.RNA

d.DNA

e.The central dogma

Answer: b

4.Which of the following is a stop codon?

a.UAA

b.UGC

c.UAC

d.UUA

e.UGG

Answer: a

5.The termination of transcription is signaled by

a.the stop codon.

b.a sequence of bases.

c.a protein bound to DNA.

d.RNA polymerase running out of template.

e.lack of deoxyribonucleoside triphosphates.

Answer: b

6.Which of the following is the correct order in which a charged tRNA travels?

a.E site, P site, A site, T site

b.P site, E site, A site, T site

c.T site, A site, P site, E site

d.A site, T site, E site, P site

e.E site, P site, T site, A site

Answer: c

7.Which of the following single base substitutions in the sense strand of DNA would cause a change in phenotype?

a.CCT to CCC

b.GAG to TAG

c.ATG to ATT

d.CTG to CTT

e.CAA to CAG

Answer: c

8.Which of the following is a function of tRNA?

a.tRNA is the main constituent of ribosomes.

b.tRNA transports amino acids.

c.tRNA acts as a template for translation.

d.tRNA recognizes four bases on the mRNA.

e.tRNAs all carry the same anticodon.

Answer: b

9.Which of the following about the genetic code is true?

a.The genetic code is degenerate.

b.The genetic code changes a great deal over short periods of time.

c.The genetic code is ambiguous.

d.The genetic code has 64 codons that code for amino acids.

e.The genetic code is completely different for prokaryotes and eukaryotes.

Answer: a

10.A mutation that occurs when a mutagen causes a permanent change in DNA is

a.inversion.

b.deletion.

c.duplication.

d.induced mutation.

e.translocation.

Answer: d

11.Put the following events about protein synthesis in chronological order :

1) After peptide linkage, the empty P site tRNA shifts to an exit site on the ribosome.

2) The ribosome releases the empty tRNA as it translocates the length of one codon.

3) The next tRNA binds the A site.

4) A tRNA is positioned at the AUG start codon.

5) The amino acid at the P site is transferred to the amino acid attached to the tRNA at

the A site.

6) The A site is now free for the next incoming tRNA.

a. 4, 1, 5, 3, 6, 2

b. 4, 6, 1, 2, 3, 5

c. 4, 1, 5, 2, 3, 6

d. 4, 3, 5, 1, 2, 6

e. 4, 2, 5, 1, 3, 6

Answer: d

12.Triplet codons

a. can have amino acids that are represented by more than one codon and are not specific.

b. are tRNA codons.

c. are not relatively universal and change frequently over time.

d. help bind the promoter and unwind the DNA strands.

e. can be stop codons or start codons.

Answer: e

13.Anticodons are made of mRNA.

a. true

b. false

Answer: b

14.An initiator methionine-tRNA complex is positioned at the AUG start codon in order to start elongation in protein synthesis.

a. true

b. false

Answer: a

15.The main difference between DNA and RNA is that

a. RNA lacks pyrimidine bases.

b. DNA lacks purine bases.

c. DNA lacks a 2' hydroxyl group.

d. RNA lacks a 2' hydroxyl group.

e. Both a and c

Answer: c

16.RNA polymerase

a. adds nucleotides to the 3' hydroxyl group of the last nucleotide.

b. functions similarly to DNA polymerase.

c. adds nucleotides to the 5' hydroxyl group of the last nucleotide.

d. Both a and b

e. Both b and c

Answer: d

17.Which of the following is not a phase that occurs during translation?

a. Termination

b. Initiation

c. Conjugation

d. Elongation

e. All of these phases occur in translation.

Answer: c

Chapter 16

TEST FILE QUESTIONS

Fill in the Blank

1. A _______ animal has recombinant DNA integrated into its own genetic material.

Answer: transgenic

2. Enzymes that cleave double-stranded DNA at specific sites are _______.

Answer: restriction enzymes

3. A short, single-stranded region at the end of a DNA _fragment is a _______.

Answer: sticky end

4. An enzyme that can covalently link two DNA fragments is _______.

Answer: DNA ligase

5. A _______ is a virus or plasmid that can replicate its DNA and foreign DNA within a cell without being degraded.

Answer: cloning vector

6. A circular cloning vector that replicates autonomously within a cell is a _______.

Answer: plasmid

7. A cloning vector that replicates and destroys a bacterial cell is a _______.

Answer: bacteriophage

8. _______ is obtained by reverse transcription of RNA.

Answer: Complementary DNA

9. A collection of DNA molecules that represents a population of RNAs is a _______.

Answer: cDNA library

10. DNA of the bacterial host is not cleaved by its own restriction enzymes because of the activity of specific _______, which add methyl groups to certain bases within the recognition sites.

Answer: methylases

11. Restriction enzymes recognize sites by a _______ sequence of bases.

Answer: specific

12. An organism’s DNA is isolated, cut by restriction endonucleases, and inserted into vectors where it is cloned. The result is a collection of clones called a _______.

Answer: genomic library

13. In order to synthesize cDNA from mRNA, an important retroviral enzyme called _______ is essential.

Answer: reverse transcriptase

14. VNTR stands for “_______.”

Answer: variable number of tandem repeats

15. An undifferentiated cell that divides and differentiates into specialized cells is a _______.

Answer: stem cell

16. A natural way of inhibiting mRNA translation catalyzes the breakdown of the targeted mRNA. This technique uses _______.

Answer: interference RNA (or RNAi)

17. A system that tests for protein interactions in a living cell is the _______.

Answer: two-hybrid system

18. The characterization of an individual by his or her DNA base sequence is known as _______.

Answer: DNA fingerprinting

ONLINE QUIZ QUESTIONS

1.Restriction endonucleases (enzymes)

a.cleave single-stranded DNA.

b.are used by some bacteria as a defense against invading pathogens.

c.are inserted into bacteria by man-made vectors.

d.are made only by eukaryotic cells.

e.phosphorylate ADP to ATP.

Answer: b

2.Sticky ends are

a.double-stranded ends of DNA fragments.

b.identical for all restriction enzymes.

c.removed by restriction enzymes.

d.complementary to other sticky ends generated by the same restriction enzyme.

e.hundreds of bases long.

Answer: d

3.In gel electrophoresis,

a.DNA fragments are separated on the basis of size.

b.DNA does not have an electric charge.

c.DNA fragments cannot be removed from the gel.

d.the electric field separates positively charged DNA fragments from negatively charged DNA fragments.

e.the DNA fragments are naturally fluorescent.

Answer: a

4.Genes that are associated with recombinant DNA in host cells allowing the identification of cells incorporating the recombinant DNA are known as

a.reporter genes.

b.plasmid vectors.

c.announcer genes.

d.gene libraries.

e.marker genes.

Answer: a

5.A labeled fragment of DNA that is complementary to a target region of DNA and which is used for hybridization to the target is called

a.a ligase.

b.a restriction fragment.

c.a probe.

d.a vector.

e.a VNTR.

Answer: c

6.The use of living cells to produce materials useful to people is called

a.a knockout experiment.

b.homologous recombination.

c.biotechnology.

d.the two-hybrid system.

e.DNA fingerprinting.

Answer: c

7.Restriction enzymes cleave DNA at specific sequences of bases called

a.restriction sites.

b.plasmid vectors.

c.enzyme ports.

d.ligand recognition sites.

e.restriction ports.

Answer: a

8.All of these are ways that DNA manipulation is changing agriculture except

a.creating plants that are unpalatable to farm animals.

b.creating plants that make their own insecticide.

c.making crops more resistant to herbicide.

d.creating transgenic organisms expressing useful genes.

e.creating plants with better nutritional profiles.

Answer: a

9.The manipulation and combination of DNA molecules from different sources is called

a.electrophoresis.

b.replication unit processing.

c.restriction endonuclease activity.

d.biotechnology.

e.recombinant DNA technology.

Answer: e

10.Which of the following is not an argument made against the use of genetically altered plants?

a.It is not nice to fool with Mother Nature.

b.Genetically altered foods are unsafe to eat.

c.Genetically altered crop plants could be dangerous to the environment.

d.The genes inserted to make transgenic crops are unknown.

e.Use of genetically altered crops could have unintended consequences.

Answer: d

11.DNA chip technology is useful because it

a. permits genes to mutate freely.

b. conforms to the binding sites of cells or tissues.

c. determines which genes are expressed by a cell or tissue.

d. a and b.

e. None of the above

Answer: c

12.Probes

a. are arrays of 60,000 or more different DNA sequences.

b. are single-stranded.

c. usually are 20 nucleotides long.

d. represent unique regions in the genome.

e. All of the above

Answer: e

13.A scientist used DNA chip technology on a tissue culture from a rabbit's mouth and the scanner produced the following results: blue spots, but no red or yellow spots. Which conclusion is the most probable?

a. There was hybridization to cDNA from cancerous tissue and hybridization to cDNA from both cancerous and normal tissues.

b. There was hybridization to cDNA from normal tissue and hybridization to cDNA from both cancerous and normal tissues.

c. There was hybridization to cDNA from normal tissue and hybridization to cDNA from cancerous tissue.

d. No hybridization occurred.

e. None of the above

Answer: c

Chapter 26

TEST FILE QUESTIONS

Fill in the Blank

1. The mechanisms of morphological change were not understood until discoveries were made in_______.

Answer: biochemistry

2. Molecular evolution studies the patterns of _______ in molecules and the process by which this is achieved.

Answer: evolutionary change

3. A _______ mutation is the partial or complete replacement of a nucleotide base or longer sequence by another throughout an entire population or species.

Answer: substitution

4. According to the hypothesis of _______, most of the variability in molecules measured by evolutionists does not affect their functioning.

Answer: neutral evolution

5. _______ is a molecule similar to hemoglobin that has a greater affinity for oxygen.

Answer: Myoglobin

6. Lungfishes and lilies have more _______ DNA than humans but less of it is _______ DNA.

Answer: total; coding

7. If a protein has consistent changes over time, then its _______ ticks at a constant rate.

Answer: molecular clock

8. DNA that has changed little during evolution probably has the same _______ in all species.

Answer: function

9. A visual representation of the evolutionary relationship between species is called a _______.

Answer: gene tree

10. Morphological traits are not useful for comparisons between bacteria and humans because these organisms lack_______.

Answer: comparable structures

11. In studying lysozyme, researchers found that five amino acid substitutions on its surface affect its biological _______.

Answer: activity

12. Evidence suggests that the three families of globin genes arose as gene _______.

Answer: duplications

13. Langurs and cows share a very similar _______ molecule.

Answer: lysozyme

14. To infer times of the most ancient splits in lineages, scientists must study _______ that are found in all organisms and that evolve slowly.

Answer: molecules

15. A _______ is a group of homologous genes with related functions that have been produced by successive rounds of duplication and mutation.

Answer: gene family

TEXTBOOK SELF QUIZ QUESTIONS

1. Which of the following questions do students of genomic evolution not try to answer?

a. What are the forces that maintain interactions among different genes?

b. Why are the genomes of organisms so variable in size?

c. How has enlargement of genomes been accomplished?

d. Why is DNA the genetic material of most organisms?

e. How do proteins acquire new functions?

2. Molecular evolution differs from phenotypic evolution in which of the following ways?

a. It requires changes in molecules if it is to happen.

b. Random genetic drift and mutations usually exert greater influences on rates and directions of molecular evolution than on rates and directions of phenotypic evolution.

c. Molecular evolution is not influenced by natural selection.

d. Rates of molecular evolution are much slower than rates of phenotypic evolution because mutation rates typically are low.

e. There are no important differences between molecular and phenotypic evolution.

3. Choosing the appropriate molecule for phylogenetic reconstruction does not require a consideration of the

a. question being answered.

b. rate of evolution of the molecule.

c. phylogenetic distribution of the molecule.

d. function of the molecule.

e. completeness of the fossil record.

4. Ribosomal RNA sequences are useful for addressing the evolutionary relationships of lineages that diverged in ancient times because they

a. evolve at a rapid rate.

b. have undergone convergent evolution in many lineages.

c. are molecules that all organisms have.

d. consist of mainly neutral characters.

e. are difficult to align.

5. Mitochondrial DNA sequences are useful in studying the recent evolution of closely related species because

a. some mitochondrial genes accumulate mutations very rapidly.

b. they are paternally inherited.

c. they evolve only in a neutral fashion.

d. they are highly constrained in function.

e. they recombine every generation.

6. Issues concerning patterns of molecular evolution include

a. evolutionary relationships among molecules.

b. molecular clock.

c. rate of mutation for neutral characters.

d. the importance of gene duplication in evolution.

e. All of the above

7. Molecules are used to reconstruct phylogenies even if a fossil record is available, because

a. the more characters the better.

b. molecules are more accurate characters than are fossils.

c. molecules undergo less homoplasy than do fossil characters.

d. molecules are less subjective characters than are fossils.

e. molecules give us the “right” phylogeny.

8. Neutral characters

a. are not evolving under the influence of natural selection.

b. have a neutral pH.

c. are not useful in reconstructing phylogenies.

d. are subject to strong functional constraints.

e. are not likely to evolve.

9. The concept of a molecular clock implies that

a. many proteins show a constancy in rate of change with time.

b. organisms evolve at a constant rate.

c. one can date evolutionary events with molecules alone.

d. all molecules change at the same rate in evolution.

e. we can predict how rapidly all genes will evolve.

10. Proteins acquire new functions primarily by means of

a. gene duplication, which frees one copy of a gene from having to perform its original function.

b. gene duplication, which provides two copies of a gene that, working together, produce a new protein.

c. deletions, which generate new protein shapes.

d. deletions, which make proteins nonfunctional, thereby creating new opportunities for other proteins.

e. None of the above

11. The lysozyme story suggests that

a. molecules cannot change their function in evolution.

b. selection does not act at the molecular level.

c. molecules can help us understand the process of organismic evolution.

d. all organisms are capable of fermenting bacteria.

e. lysozyme has a very accurate molecular clock.

12. The actual differences in genome sizes are much less than the apparent differences because

a. multicellular organisms are really not that much more complicated than eukaryotic protists.

b. organisms with the largest amounts of nuclear DNA have much more noncoding DNA than organisms with smaller amounts of nuclear DNA.

c. the sizes of many apparently large genomes have been seriously overestimated.

d. differences in the sizes of genes account for much of the apparent difference in genome sizes.

e. species with large genomes preferentially lose DNA by converting it to pseudogenes, which are subsequently lost.

Answers

1. d

2. b

3. e

4. c

5. a

6. e

7. a

8. a

9. a

10. a

11. c

12. b

ONLINE QUIZ QUESTIONS

1.Questions about the process of molecular evolution address

a. whether molecules evolve.

b. how molecules change with time.

c. how to reconstruct phylogenies of extinct organisms.

d. the evolutionary relationships among molecules.

e. the origin of organismal diversity.

Answer: b

2.The full set of genes an organism contains is called

the genome.

a gene library.

a mutation.

a pseudogene.

a similarity matrix.

Answer: a

3.The field of study that investigates the evolution of macromolecules and uses the findings to reconstruct the evolutionary history of genes and the organisms that carry them is called

a. genomic inquiry.

b. evolutionary theory.

c. Cladisitics.

d. phylogeny study.

e. molecular evolution.

Answer: e

4.Which of the following is not true about a synonymous mutation?

a. A synonymous mutation is likely to be deleterious to the organism.

b. An example of a synonymous mutation would be a change from UUA to UUC.

c. An example of a synonymous mutation would be a change from UUA to UUG.

d. A synonymous mutation changes the amino acid sequence encoded by a gene.

e. A synonymous mutation affects the functioning of a protein.

Answer: C

5.In 1968, Motoo Kimura proposed a theory to explain how most mutations are fixed in populations based upon the observation that most mutations are neutral. This theory is called

a. the neutral theory of molecular evolution.

b. Kimura’s postulate.

c. genetic drift.

d. natural selection.

e. the neutral expression hypothesis.

Answer: a

6.Duplicate copies of genes that have undergone one or more mutations that eliminate their ability to be expressed are called

a. duplicate genes.

b. quasigenes.

c. pseudogenes.

d. hemigenes.

e. non-expressed duplicate alleles.

Answer: c

7.The lysozyme story suggests that

a. molecules cannot change function in evolution.

b. selection does not act at the molecular level.

c. molecules can help us understand the process of organismal evolution.

d. all organisms are capable of fermenting bacteria.

e. lysozyme has a very accurate molecular clock.

Answer: c

8.A group of homologous genes with related function, often arrayed in tandem along a chromosome is called

a. a gene family.

b. a genome.

c. a gene tree.

d. a pseudogene.

e. paralogs.

Answer: a

9.Genes that are related through gene duplication events in a single lineage are called

a. a gene family.

b. a genome.

c. a gene tree.

d. a pseudogene.

e. paralogs.

Answer: e

10.Jurassic Park is unlikely ever to be a reality because

a. we cannot obtain DNA from ancient organisms.

b. we have no parks big enough for such large dinosaurs.

c. although we can obtain DNA from dinosaur fossils, it is highly fragmented.

d. the genetic code used by dinosaurs is different from all other organisms.

e. we wouldn't know what to feed the dinosaurs.

Answer: c