A prokaryotic cell has which of the following?

a. centriolesb. lysosomesc. plasma membraned. mitochondria

Answer: c

Which of these is a true statement?

a. Both plasmids and viruses can serve as vectors.b. Plasmids can carry recombinant DNA but viruses cannot.c. Vectors carry only the foreign gene into the host cell.d. All of these statements are true.

Answer: a

Which of these is found in all viruses?

a. envelope, nucleic acid, capsidb. DNA, RNA, proteinsc. proteins and a nucleic acidd. proteins, nucleic acids, carbohydrates, and lipidse. reverse transcriptase

Answer: c

a. DNA ligaseb. DNA polymerasec. RNA polymerased. Restriction enzymee. Reverse transcriptase

1. Enzyme found in retroviruses that produce DNA from an RNA template.2. Enzyme used during replication to attach Okazaki fragments to each other.3. Enzyme used during transcription to produce mRNA.

Answer: e

Answer: a

Answer: c

Chemosynthetic bacteria

a. are autotrophicb. use the rays of the sun to acquire energy.c. oxidize inorganic compounds to acquire energy.d. give off oxygen.e. Both a and c are correct.f. Both b and d are correct

Answer: e

Which of the following is NOT a form ofgenetic recombination in bacteria?

a. binary fissionb. conjugationc. transductiond. transformatione. All are forms of recombination.

Answer: a

A bacterium produces vitamins for a hostwhile gaining a habitat. This relationship is

a. commensalism.b. mutualism.c. parasitism.d. predation.e. competition.

Answer: b

Which of the following is NOT a correctcontrast between bacteria and eukaryotes?

Bacteria Eukaryotesa. binary fission mitotic cell divisionb. nucleoid nucleusc. asexual only asexual and sexuald. nonmotile motilee. no membrane bound membrane bound organelles organelles

Answer: d

Which of these is (are) a true statement(s)?

a. Archaea are in a separate kingdom.b. Archaea are in their own domain.c. Archaea are found in most every habitat.d. Archaea are found in extreme habitats like swamps, salty lakes, hot, acidic aquatic habitats.e. Both b and d are correct.

Answer: e

The binding of an active repressor molecule at this site prevents transcription.

a. operonb. operatorc. promotord. repressore. corepressor

Answer: b

The working of the lac operon is important forwhich of the following reasons?A. It represents a principal means by which genes are regulated in prokaryotes.B. It represents a principal means by which genes are regulated in eukaryotes.C. It illustrates the complexities of rRNA transcription.D. It provided the first clues to how DNA replication is controlled during the cell cycle.E. The understanding of it lead to the development of an economical means for the biological production of lactose.

Answer: a

Which of the following statements about plasmidsis correct?

a. They are synthesized in the endoplasmic reticulum.b. They are found only in eukaryotic cells.c. They are composed of RNA.d. They are larger in size than bacterial chromosomes.e. They are self-replicating.

Answer: e

Which of the following is NOT a potential controlmechanism for regulation of gene expression ineukaryotic organisms?

a. The degradation of RNAb. The transport of mRNA from the nucleusc. The lactose operond. Transcription

Answer: c

a. Transcriptionb. Translationc. Transposond. DNA methylatione. Histone acetylation

1. A mobile segment of DNA that travels from onelocation on a chromosome to another, one element of genetic change.

2. The addition of groups to certain bases of DNAafter DNA synthesis; this is thought to be an important control mechanism for gene expression.

3. The synthesis of polypeptides from the genetic information coded in mRNA.

Answer: c Answer: d

Answer: b

The actions of which of the following enzymesare responsible for ensuring that chromosomes do not decrease in length with every round of replication?

a. Telomeraseb. DNA ligasec. Helicased. Primase

Answer: a

a. tRNAb. mRNAc. Poly-A taild. RNA polymerasee. r RNA

1. An example of post-transcriptional modification

2. Binds to the promoter on DNA to initiate transcription.

3. Along with proteins, comprises ribosomes

4. Binds to free amino acids in the cytoplasm

Answer: c

Answer: dAnswer: e

Answer: a

The expression of eukaryotic genes can be Controlled at all of the following stages of Protein synthesis EXCEPT

a. Initiation of transcriptionb. RNA processingc. Degradation of proteind. Acetylation of DNA

Answer: d

One of the characteristics of retrotransposons is that

a. They code for an enzyme that synthesizes DNA using an RNA template.

b. They are found only in animal cellsc. They contribute a significant portion of the genetic

variability seen in a population of gametesd. They generally move in a cut and paste

mechanism

Answer: a

Which of the following shows the steps of an HIV viral infection in the proper order?

a. Virus locates cell, enters nucleus, alters host cellDNA, destroys the cell membrane

b. Virus locates cell, alters host DNA, host cell produces copies of virus, copies enter hostcell nucleus, nucleus leaves cell

c. Virus locates cell, penetrates cell membrane, enters nucleus, alters host cell DNA, host cellproduces copies of virus

d. Virus locates cell, enters cell, changes RNA to DNA, host cell produces copies of virus Answer: d

Which of the following is a difficulty in gettingprokaryotic cells to express eukaryotic genes?

a. The signals that control gene expression aredifferent and prokaryotic promoter regions must be added to the vector.

b. The genetic code differs because prokaryotessubstitute the base uracil for thymine.

c. Prokaryotic cells cannot transcribe intronsbecause their genes do not have them.

d. The ribosomes of prokaryotes are not largeenough to handle long eukaryotic genes.

Answer: a

Lactose digestion in E. coli begins with its hydrolysis by the enzyme b-galactosidase. The gene encoding b-galactosidase, lacZ, is part of a coordinately regulated operon containingother genes required for lactose utilization. Which of the following figures correctly depicts theinteractions at the lac operon when lactose is NOT being utilized? (The legend below defines the shapes of the molecules illustrated in the options.)

A.

B.

C.

D.

A. Picture Choice 1B. Picture Choice 2C. Picture Choice 3D. Picture Choice 4

Answer: D

Arctic foxes typically have a white coat in the winter. In summer, when there is no snow on the ground, the foxes typically have a darker coat. Which of the following is most likely responsible for the seasonal change in coat color?a. The decrease in the amount of daylight in winter causes

a change in gene expression, which results in the foxes growing a lighter appearing coat.

b. The diet of the foxes in summer lacks a particular nutrient, which causes the foxes to lose their white coat and grow a darker colored coat.

c. Competition for mates in the spring causes each fox to increase its camouflage with the environment by producing a darker appearing coat.

d. The lower temperatures in winter denature the pigment molecules in the arctic fox coat, causing the coat to become lighter in color. Answer: a

During development, individual cells of the same organism begin to produce different proteins because

a. the cells have different numbers of chromosomes.

b. not all cells can synthesize protein.c. specific genes are activated in the

cells.b. the cells have different kinds and

amounts of DNAAnswer: c

According to the Jacob-Monod model of the lac operon, the regulator gene does which of the following?

a. Specifies the amino acid sequence of the enzyme.

b. Controls the activity of histones.c. Determines whether promoter genes

will be translated.d. Directs the synthesis of a repressor

protein.Answer: d

A tobacco plant can be made to express a gene from fireflies, resulting in the emission of light. Which of the following is the basis for this phenomenon?

a. Chloroplasts can be made to produce light if firefly proteins are injected into plant cells.

b. Fireflies and tobacco plants share a recent common ancestor.

c. Transcription and translation are fundamentally similar in both fireflies and tobacco plants.

d. Most enzymes in fireflies have the same amino acid sequence as the enzymes in tobacco plants. Answer: c

The FtsZ protein is present in prokaryotes and in chloroplasts. The protein is structurally and functionally similar to tubulin proteins of eukaryotic cells. Which of the following is a likely conclusion to draw from this information?

A. FtsZ and tubulin proteins were both present in a common ancestor.

B. Microtubules are involved in the mechanics of photosynthesis.

C. Tubulin genes are evolutionarily derived from the gene that codes for the FtsZ protein.

D. The sequences of the genes encoding the FtsZ and tubulin proteins are identical.

Answer: C

The human genome appears to have only one-third more genes than the simple nematode C elegans. Which of the following best explains how the more complex humans can have relatively few genes?A. The unusually long introns in human genes are

involved in regulation of gene expression.

B. More than one polypeptide can be produced from a gene by alternative splicing.

C. Human genes code for many more types of domains.

D. The large number of SNPs (single nucleotide polymorphisms) in the human genome provides for a great deal of genetic variability.

Answer: B

Multigene families are

A. groups of enhancers that control transcription.

B. usually clustered at the telomeres.

C. equivalent to the operons of prokaryotes.

D. sets of identical or similar genes that have evolved by duplication.

Answer: D

Transposons

A. Are found only in animal cells.B. Generally move by a cut and paste

mechanism.C. Contribute a significant portion of

the genetic variability seen within a population of gametes.

D. Amplification is dependent on a retrovirus.

Answer: B

Comparative genomics

A. assigns functions to the products of genes.

B. assigns functions to regulatory sequences.

C. compares genes in different organisms to see how those organisms are related physiologically.

D. Both a and cAnswer: C