Supercoiling of circular chromosomes, such as bacteria

11 Jun Supercoiling of circular chromosomes, such as bacteria

Question
Question 12
Supercoiling of circular chromosomes, such as bacterial chromosomes, is usually:…

a) negative, because it compacts the chromosome more efficiently.

b) none. Supercoiling is a concept that applies only to linear chromosomes.

c) negative, because it makes unwinding the DNA easier.

d) positive, because it compacts the chromosome more efficiently.

e) positive, because it makes unwinding the DNA easier.

Question 13

Telomeres…

a) protect other parts of chromosomes from degradation.

b) can be rebuilt using an RNA polymerase.

c) all of the other answers are correct.

d) are shortened over time by a DNA exonuclease.

e) are highly conserved between species.

Question 1

Like DNA replication, transcription requires:

A) deoxyribonucleotide monomers.

b) a DNA polymerase.

c) a primase.

d) a template strand of DNA.

Question 2

Which of the following does NOT happen to an mRNA precursor (primary transcript) as it is converted into a mature mRNA in the nucleus?

a) a sequence of adenines is added to the 3′ end

b) the introns are removed

c) the 5′ end is capped with methylated Guanosine

d) The Ts are converted to Us

the exons are spliced together

Question 4

RNA secondary structures include (choose all that apply):

a) stem-loop.

b) None – RNA does not have a secondary structure.

c) helix loop helix.

d) hairpin.

e) supercoiling.

tQuestion 6

Termination of transcription ___

a) requires the rho factor binding a stop transcription sequence.

b) can be rho-dependent or independent.

c) occurs when RNA polymerase binds the template DNA.

d) happens when the nascent transcript forms a stem loop that terminates transcription.

e) happens when the rho protein phosphorylates RNA polymerase.

Question 7

The RNA world hypothesis has developed from the observation that RNA can serve many diverse biochemical functions. However, which of the following is most likely NOT one of them…?

a) replicate sequences.

b) catalyze peptide bond formation.

c) synthesize ATP.

d) carry hereditary information

e) cut sequences out.

Question 8

The role of sigma factors in bacterial transcription is to

a) hydrolyze phosphate bonds in the NTP added to the nascent RNA molecule.

b) bind the consensus sequences to identify the start site for transcription.

c) instruct the RNA polymerase where to stop transcription.

d) provide the first nucleotide in the nascent RNA molecule.

e) unwind the DNA to initiate transcription.

Question 9

Types of RNA include… (choose all that apply):

a) cmRNA (cell membrane RNA), which is used to produce membrane proteins.

b) mRNA (messenger RNA), which is used to translate proteins.

c) snRNA (small nuclear RNA), which is used in mRNA processing.

d) siRNA (small interfering RNA), which targets mRNA for breakdown.

e) miRNA (microRNA), which inhibits translation.

Question 10

Which of the following is NOT a step required for transcription in bacteria ?

a) recognition of the promoter by RNA molecules.

b) hydrolysis of a ribonucleotide.

c) formation of the first phosphodiester bonds between rNTPs.

d) movement of the RNA polymerase from the promoter.

e) unwinding of DNA forming a transcription bubble.