Week 6 Discussion

What is the primary function of the promoter in transcription?

• It codes for the start codon of RNA

• It determines the stability of RNA polymerase

• It is the site where RNA polymerase binds to initiate transcription

• It recruits ribosomes to the RNA strand

How does RNA polymerase differ from DNA polymerase in initiating synthesis?

• RNA polymerase requires a primer while DNA polymerase does not

• RNA polymerase needs helicase to open the DNA strands

• DNA polymerase can synthesize de novo, but RNA polymerase cannot

• RNA polymerase can initiate RNA synthesis without a primer

Which of the following best describes an enhancer’s role in transcription?

• Synthesizes primers for RNA polymerase

• Encodes for non-coding RNA

• Determines the stability of RNA polymerase on the promoter

• Signals where transcription should terminate

Why are RNA primers needed during DNA replication but not during transcription?

• Because transcription occurs in the nucleus

• Because DNA polymerase cannot synthesize DNA without a 3’ hydroxyl group

• Because RNA polymerase does not recognize promoter sequences

• Because replication does not involve RNA at all

Why is RNA considered unsuitable as the long-term genetic molecule in cells?

• RNA lacks base pairing ability

• RNA cannot form phosphodiester bonds

• RNA is more stable than DNA

• RNA is chemically unstable due to its 2’ hydroxyl group

In RNA sequencing (RNA-seq), why is RNA transcribed into DNA before sequencing?

• RNA is harder to label with fluorescent dyes

• DNA is easier to amplify and sequence than RNA

• RNA cannot base pair

• DNA has a 2’ hydroxyl group that stabilizes it for reactions

What would happen if a dideoxynucleotide (ddNTP) is incorporated during DNA synthesis in a sequencing reaction?

• DNA polymerase would pause but continue synthesis

• The DNA strand would loop back and continue replicating

• Synthesis would terminate because there is no 3’ hydroxyl group

• The primer would detach and restart the process

What determines the length of a PCR product?

• DNA polymerase’s proofreading activity

• The concentration of ddNTPs

• Extension time and the polymerase’s synthesis rate

• The location of enhancer elements in the DNA

What is true about the primer used in PCR?

• It is removed during PCR and replaced with DNA

• It is only used to mark the end of synthesis

• It becomes part of the PCR product and defines the 5’ end of the new strand

• It hybridizes to RNA to initiate reverse transcription

In the experiments conducted by Jacob, Monod, and Lwoff, why does cell growth slow down in between media switches from glucose to lactose?

• Cells cannot grow because B-galactosidase only exists in glucose media.

• Bacteria cannot grow in lactose media because it inhibits B-galactosidase.

• • B-galactosidase expression is low in glucose and cell growth slows down.

• Switching from glucose to lactose media is so abrupt that cells pause gene expression.