Exam 3 Clicker Questions

During elongation, an incoming aminoacyl-tRNA is initially bound to the ribosome

a. At the A site

b. At the P site

c. At the E site

d. At the R site

at the A site

Primary protein structure is

A. held together by amide functional groups.

B. the only level of protein structure formed by all covalent bonds

C. held together by peptide bonds.

D. all of the above

all of the above

If a cell always needs to express a gene for “house keeping” purposes, that gene is said to be __________ \\n

A. Repressible

B. Inducible

C. Promotable

D. Constitutive

constitutive

• E. coli can utilize galactose as a sole carbon source. To do so, they need to express the three genes of the gal operon (galA, galB, and galC) whose products encode proteins that convert galactose to glucose

• These genes are expressed at high level only when galactose is present \\n in the environment. When glucose is present, however, expression of \\n the gal operon is greatly reduced even when galactose is also available

• Deletion of a gene called galR in a different region on the chromosome \\n causes the gal operon to be expressed at high level when cells are \\n growing in a medium that contains any one of many sugars other thanglucose

What is the role of the galR gene product?

A. Positive regulator of the galactose operon

B. Negative regulator of the galactose operon

C. Sigma factor for the galactose operon

D. Doesn’t regulate the galactose operon

doesn’t regulate the galactose operon

Vibrio fischeri regulates the expression of Luciferase, an enzyme that makes it bioluminescent, by utilizing quorum sensing. During \\n what stage of a growth curve of Vibrio fischeri, would you expect \\n to see the strongest bioluminescence? \\n

A. lag phase \\n

B. exponential (log) phase \\n

C. stationary phase \\n

D. death phase

exponential (log) phase

What do all viruses contain? \\n

A. A genome and an envelope \\n

B. A capsid and an envelope \\n

C. A capsid and a genome \\n

D. A capsid, an envelope, and a genome

a capsid and genome

In your analysis of a viral genome you find that it lacks a gene for DNA polymerase and consists of 29% adenine (A), 17% thymine (T), 32% cytosine (C), and 22% guanine (G). What can we determine about the viruses genome? \\n

A. Double-stranded DNA virus \\n

B. Single-stranded DNA virus \\n

C. Double-stranded RNA virus \\n

D. (+) Single-stranded RNA virus

single-stranded DNA viruses

Which of the following attributes of living things is not \\n true of viruses? \\n

A. Viruses utilize nucleic acids as their information store. \\n

B. Viruses have genes. \\n

C. Viruses depend on protein synthesis. \\n

D. Viruses have independent metabolism

viruses have independent metabolism

Place the following events of a viral replication cycle into their correct order starting with: \\n

1\. entry into the cell \\n

2\. exit from cell \\n

3\. replicate genome \\n

4\. assemble viral particles \\n

5\. synthesize viral proteins \\n (/ means can happen simultaneously) \\n

A. 1, 5, 4, 3, 2 \\n

B. 1, 3/5, 2, 4 \\n

C. 1, 3/5, 4, 2 \\n

D. 1, 3, 2, 5, 4 \\n

E. 1, 4, 3/5, 2

1, 3/5, 4, 2

What does the bacteriophage T4 possess? \\n

A. An icosahedral “head” and a helical “neck” \\n

B. A helical “head” and an icosahedral “neck” \\n

C. An icosahedral “neck” and “tail” \\n

D. A helical “neck” and “tail”

an icosahedral “head” and a helical “neck”

Lambda (λ) phage infects a bacteria growing in \\n nutritionally poor growth media. Which of the \\n following statements is TRUE. \\n

A. Lambda (λ) phage will enter the lysogenic cycle due to high levels of \\n CII, which is a direct positive regulator of CI repressor expression. \\n

B. Lambda (λ) phage will enter the lysogenic cycle due to high levels of \\n CIII, which is a direct negative regulator of CI repressor expression. \\n

C. Lambda (λ) phage will enter the lysogenic cycle due to low levels of \\n CII, which is a direct positive regulator of CI repressor expression. \\n

D. Lambda (λ) phage will enter the lysogenic cycle due to low levels of \\n CIII which which is a direct negative regulator of CI repressor \\n expression.

lambda (λ) phage will enter the lysogenic cycle due to high levels of

Studies of bacterial defense mechanisms against \\n bacteriophage infection have yielded important \\n reagents that are used today to manipulate DNA and \\n RNA sequences in the laboratory.

Which of the \\n following exemplify these advancements? \\n

A. Restriction endonucleases \\n

B. Cell-surface receptors \\n

C. Signaling molecules \\n

D. Toxin-release mechanisms

restriction endonucleases

When a mutation caused by a nucleotide pair \\n substitution occurs in a protein coding region, which of \\n the following effects is least likely to occur? \\n

A. silent \\n

B. frameshift \\n

C. missense \\n

D. nonsense

frameshift

Which function does DNA polymerase use to \\n repair mismatches during replication? \\n

A. Proofreading \\n

B. Excision repair \\n

C. Light repair \\n

D. Mismatch repair

proofreading

The protein _______ is the activator of the SOS \\n response. \\n

A. RecA \\n

B. LexA \\n

C. LigD \\n

D. UvrD

RecA

Gene transfer from one bacterium to another by means \\n of a bacteriophage is called _______, whereas _______ \\n involves the transfer of DNA following cell-to-cell contact. \\n

A. transformation; conjugation \\n

B. transduction; transformation \\n

C. transduction; conjugation \\n

D. conjugation; transduction \\n

E. conjugation; transformation

transduction; conjugation

Which of the following does NOT support the theory of \\n endosymbiosis in the development of mitochondria? \\n

a) Mitochondria contain an inner membrane. \\n

b) Mitochondria contain their own reduced genome. \\n

c) Mitochondria contain rigid cell walls. \\n

d) Mitochondria contain 70s ribosomes.

mitochondria contain rigid cell walls