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

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

Helicase

Question 3

Which of the following statements about ribosomes is TRUE?

Accepted Answer

Prokaryotic and eukaryotic ribosomes differ in size and structure, which is significant for antibiotic targeting.

Question 4

A scientist wants to amplify a specific DNA fragment in the laboratory. Which technique should they use?

Accepted Answer

Polymerase Chain Reaction (PCR)

Question 5

Which of the following is a correct description of a missense mutation?

Accepted Answer

A mutation that results in a codon coding for a different amino acid.

Question 6

Which of the following is a real-world application of recombinant DNA technology in agriculture?

Accepted Answer

Production of Bt toxin-expressing crops for pest resistance

Question 7

A patient is diagnosed with a viral infection that remains dormant in nerve cells and can reactivate years later. Which type of infection is this?

Accepted Answer

Latent viral infection

Question 8

Which of the following statements about the lac operon in E. coli is correct?

Accepted Answer

The presence of glucose represses the expression of the lac operon even if lactose is available.

Question 9

Which of the following best explains the difference between vertical and horizontal gene transfer?

Accepted Answer

Vertical gene transfer is from parent to offspring, while horizontal gene transfer is between unrelated organisms.

Question 10

Which of the following is a function of DNA ligase during DNA replication?

Accepted Answer

Joining Okazaki fragments on the lagging strand

Question 11

A researcher uses a restriction enzyme to cut DNA at specific sequences. What is the main purpose of this step in recombinant DNA technology?

Accepted Answer

To generate DNA fragments with sticky or blunt ends for cloning

Question 12

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation does not use the electron transport system and produces less ATP than aerobic respiration.

Question 13

Which of the following is a unique feature of viruses compared to bacteria?

Accepted Answer

Viruses are obligate intracellular parasites and lack cellular structure.

Question 14

Which of the following best describes the function of the enzyme reverse transcriptase?

Accepted Answer

It synthesizes DNA from an RNA template.

Question 15

A scientist is using gel electrophoresis in a forensic investigation. What is the main purpose of this technique?

Accepted Answer

To separate DNA fragments based on size

Question 16

Which of the following is the final electron acceptor in aerobic respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 17

Which of the following statements about plasmids is correct?

Accepted Answer

Plasmids can carry antibiotic resistance genes and be transferred between bacteria via conjugation.

Question 18

Which of the following best describes a frame shift mutation?

Accepted Answer

A mutation caused by insertion or deletion of nucleotides that changes the reading frame of the gene.

Question 19

Which of the following is a therapeutic application of recombinant DNA technology?

Accepted Answer

Production of human insulin in bacteria

Question 20

A patient is exposed to UV radiation, which causes the formation of thymine dimers in DNA. What type of mutation is most likely to result?

Accepted Answer

Induced mutation

MCB2000 Exam Two Study Guide – Step-by-Step Microbiology Guidance

Study Guide - Practice Questions