Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

Which enzyme is responsible for synthesizing RNA from a DNA template during transcription in prokaryotes?

Accepted Answer

RNA polymerase

Question 3

A mutation changes a single nucleotide in the coding region of a gene, resulting in a different amino acid in the protein product. Which historical experiment first demonstrated that a single gene encodes a single polypeptide?

Accepted Answer

Pauling & Ingram’s sickle cell hemoglobin study

Question 4

Which of the following is TRUE about the directionality of transcription?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Question 5

Which sequence is commonly found at the -10 position of prokaryotic promoters?

Accepted Answer

$$	ext{TATAAT}$$

Question 6

What is the role of the sigma ($$\sigma) $$subunit in prokaryotic RNA polymerase?

Accepted Answer

It recognizes and binds to promoter sequences to initiate transcription.

Question 7

Which of the following is a function of the 5’ cap added during eukaryotic mRNA processing?

Accepted Answer

It protects mRNA from degradation and assists in ribosome binding.

Question 8

A patient ingests a death cap mushroom containing $$\alpha-$$amanitin. Which cellular process is most directly inhibited?

Accepted Answer

Transcription by RNA polymerase II

Question 9

Which of the following best explains why frameshift mutations often have severe effects on protein function?

Accepted Answer

They alter the reading frame, changing every amino acid downstream of the mutation.

Question 10

Which of the following is TRUE about the genetic code?

Accepted Answer

The code is degenerate, meaning multiple codons can specify the same amino acid.

Question 11

Which of the following is a direct result of alternative splicing in eukaryotes?

Accepted Answer

A single gene can produce multiple polypeptides.

Question 12

Which of the following sequences marks the 5’ splice site in pre-mRNA introns?

Accepted Answer

$$	ext{GU}$$

Question 13

Which of the following is NOT a step in prokaryotic transcription?

Accepted Answer

Addition of a 5’ methyl cap

Question 14

A mutation in the TATA box of a eukaryotic gene would most likely affect which process?

Accepted Answer

Binding of transcription factors and initiation of transcription

Question 15

Which of the following best describes the function of spliceosomes?

Accepted Answer

They remove introns from pre-mRNA and join exons together.

Question 16

Which of the following is a stop codon in the universal genetic code?

Accepted Answer

$$	ext{UAA}$$

Question 17

During the elongation phase of transcription, which end of the growing RNA strand are new nucleotides added to?

Accepted Answer

3’ end

Question 18

Which of the following is a key difference between prokaryotic and eukaryotic transcription?

Accepted Answer

Eukaryotes require transcription factors for initiation, while prokaryotes do not.

Question 19

Which of the following best explains why a frameshift mutation can result from a splicing error in pre-mRNA?

Accepted Answer

Introns are not removed, altering the reading frame of the mRNA.

Question 20

Which of the following is a property of the genetic code that allows for silent mutations?

Accepted Answer

Degeneracy

Transcription and the Genetic Code: Cell Biology Study Notes

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