Question 1

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

Accepted Answer

Information flows from DNA to RNA to proteins.

Question 2

During transcription in prokaryotes, which of the following is NOT required for RNA polymerase to initiate RNA synthesis?

Accepted Answer

A primer

Question 3

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

Multiple codons can specify the same amino acid.

Question 4

A mutation changes the DNA sequence from 5'-TAC-3' to 5'-TAT-3' in the template strand. What is the effect on the mRNA and the resulting protein?

Accepted Answer

The mRNA codon changes, possibly altering the amino acid sequence.

Question 5

Which of the following is a key difference between DNA and RNA molecules?

Accepted Answer

DNA contains deoxyribose sugar, while RNA contains ribose sugar.

Question 6

In prokaryotic transcription, what is the role of the sigma (σ) factor in RNA polymerase?

Accepted Answer

It recognizes and binds to the promoter sequence to initiate transcription.

Question 7

Which of the following sequences is most likely to be found at the -10 region (Pribnow box) of a prokaryotic promoter?

Accepted Answer

$$	ext{TATAAT}$$

Question 8

Which of the following best describes the process of Rho-independent (intrinsic) termination in prokaryotes?

Accepted Answer

A GC-rich inverted repeat forms a hairpin loop followed by a poly-U sequence, causing RNA polymerase to dissociate.

Question 9

Which of the following post-transcriptional modifications occurs in eukaryotic mRNA but NOT in prokaryotic mRNA?

Accepted Answer

Addition of a 5’ cap

Question 10

A eukaryotic gene contains 8 exons and 7 introns. After alternative splicing, how many different mature mRNA molecules could potentially be produced?

Accepted Answer

Multiple, depending on which exons are included or skipped.

Question 11

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

Accepted Answer

RNA polymerase reads the template DNA strand in the 3’ to 5’ direction.

Question 12

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

Accepted Answer

It protects mRNA from degradation and facilitates ribosome binding.

Question 13

A patient has a mutation in a gene encoding a general transcription factor (GTF) required for RNA polymerase II function. Which process is most likely to be directly affected?

Accepted Answer

Transcription of protein-coding genes

Question 14

Which of the following best describes the relationship between the coding strand of DNA and the mRNA produced during transcription?

Accepted Answer

The mRNA is identical to the coding strand except U replaces T.

Question 15

Which of the following is a consequence of a frameshift mutation (insertion or deletion of one or two bases) within an open reading frame (ORF)?

Accepted Answer

The reading frame is altered, potentially changing all downstream amino acids.

Question 16

Which of the following is NOT a function of small nuclear ribonucleoproteins (snRNPs) in eukaryotic cells?

Accepted Answer

Adding the poly-A tail to mRNA

Question 17

Which of the following best explains why mitochondria have a slightly different genetic code than the nuclear genome?

Accepted Answer

Mitochondria evolved from bacteria and retained some differences in codon usage.

Question 18

Which of the following is a real-life example of RNA editing that changes the function of a protein?

Accepted Answer

ApoB mRNA editing, which converts a CAA codon (Gln) to a UAA stop codon, producing a truncated protein.

Question 19

Which of the following best describes the function of the polyadenylation signal (AAUAAA) in eukaryotic transcription?

Accepted Answer

It directs cleavage and addition of the poly-A tail to the pre-mRNA.

Transcription and the Genetic Code: From DNA to RNA to Protein

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