Question 1

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

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA is shorter-lived than RNA in the cell.

Question 3

A mutation in E. coli inhibits DNA polymerase proofreading activity. What is the most likely consequence?

Accepted Answer

No proofreading will occur, increasing mutation rates.

Question 4

During transcription in eukaryotes, which of the following is added to the 5' end of the pre-mRNA to protect it from degradation?

Accepted Answer

A methylated guanine cap

Question 5

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

Accepted Answer

RNA polymerase

Question 6

A scientist discovers a compound that inhibits the function of aminoacyl-tRNA synthetase. What process will be directly affected?

Accepted Answer

Attachment of amino acids to tRNAs

Question 7

Which of the following statements about the genetic code is FALSE?

Accepted Answer

Each codon can specify more than one amino acid.

Question 8

Given the DNA template strand 3' AGTCCATG 5', what is the sequence of the RNA transcript produced?

Accepted Answer

$$5'\ UCAGGUAC\ 3'$$

Question 9

Which of the following best describes the function of the spliceosome?

Accepted Answer

It removes introns and joins exons in pre-mRNA.

Question 10

In prokaryotes, why can translation begin before transcription is complete?

Accepted Answer

Prokaryotic mRNA does not require processing and both processes occur in the cytoplasm.

Question 11

A protein is 300 amino acids long. What is the minimal number of nucleotides in the coding sequence of the mRNA that codes for this protein?

Accepted Answer

$$900$$

Question 12

Which of the following is a function of the 3' poly-A tail added to eukaryotic mRNA?

Accepted Answer

It slows degradation of mRNA in the cytoplasm.

Question 13

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on codon-anticodon pairing.

Question 14

Which of the following events occurs during the elongation stage of translation?

Accepted Answer

A peptide bond forms between amino acids in the P and A sites.

Question 15

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 16

Which of the following is true about the direction of RNA synthesis during transcription?

Accepted Answer

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

Question 17

Which of the following is a direct result of a frameshift mutation in a gene?

Accepted Answer

The reading frame of the mRNA is altered, changing all downstream amino acids.

Question 18

Which of the following is NOT a function of ribosomal RNA (rRNA)?

Accepted Answer

It carries amino acids to the ribosome.

Question 19

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

Accepted Answer

Some amino acids are specified by more than one codon.

Question 20

Which of the following processes occurs in the nucleus of eukaryotic cells but not in prokaryotic cells?

Accepted Answer

RNA splicing

Gene Expression: Transcription and Translation – The Central Dogma of Biology

Study Guide - Practice Questions