Molecular Biology Practice Questions - Set A




1.         What enzymes are required for DNA replication

a.         DNA polymerase, DNA Ligase

b.         DNA polymerase, DNA Ligase, Helicases

c.         DNA Ligase only

d.         DNA Polymerase only

e.         DNA polymerase, DNA Ligase, Helicases and RNA Polymerase


2.         Which of the following pairs is mismatched?

a.         DNA polymerase─makes a molecule of DNA from a DNA template

b.         RNA polymerase─makes a molecule of RNA from an RNA template

c.         DNA ligase─joins segments of DNA.

d.         RNA polymerase─makes a molecule of RNA from a DNA template

e.         None of the above


3.         Which of the following is NOT part of the central dogma involving information transfer in cells?

a.         Replication

b.         Transformation

c.         Translation

d.         Transcription


4.         An enzyme produced in response to the presence of a substrate like lactose is called

a.         An inducible enzyme

b.         A repressible enzyme

c.         A restriction enzyme

d.         An operator

e.         A promoter


Use the following information for the next four questions:

Codon on mRNA and corresponding amino acid


UUA    leucine             UAA    nonsense

GCA    alanine             AAU    asparagine

AAG    lysine               UGC    cysteine

GUU    valine               UCG    serine

UCU    serine


5.         If the sequence of amino acids coded for by a strand of DNA is serine‑alanine‑lysine‑leucine, what is the order of bases in the strand of DNA?







6.         The antisense strand of DNA coding for the polypeptide leucine‑lysine‑leucine-serine is

a.         3'--ACAGTTTCAAT

b.         3'--AGCCGTTTCAAT

c.         3'--TCACGUUUCAAU

d.         3'--UCUCGAAAGUUA

e.         3'--AATTTCAATAGA


7.         The anticodon for asparagine is

a.         GUU

b.         UUA

c.         CTT

d.         CAA

e.         GTA


8.         What is the sequence of amino acids coded for by the following sequence of bases in a strand of DNA? (Ignore the need for a start codon)


5'--AAT  TGC  GTT  TCG--3'


a.         Leucine‑arginine‑lysine‑alanine.

b.         Asparagine‑arginine‑lysine‑alanine.

c.         Asparagine‑cysteine‑valine‑serine.

d.         Transcription would stop at the first codon

e.         Cannot be determined


9.         In the polymerase chain reaction the necessary ingredients for DNA synthesis can be mixed together in a test tube.  The DNA polymerase is from Thermus aquaticus and the template is from a human cell.  The DNA synthesized would be most similar to which of the following?

a.         Human DNA

b.         T. aquaticus DNA

c.         A mixture of human and T. aquaticus DNA

d.         Human RNA

e.         T. aquaticus RNA


10.       A mutation will result is which of the following?

a.         a change in tRNA sequence

b.         a change in rRNA sequence

c.         a change in DNA sequence

d.         a change amino acid sequence

e.         both c and d


11.       A major difference between DNA polymerase and RNA polymerase is that DNA polymerase requires which of the following?

a.         an RNA template

b.         a 3' –OH nucleotide primer

c.         uracil as one of its bases

d.         double stranded DNA

e.         nucleotide monophosphates

12.       Which of the following is not required for DNA polymerase?

            a. template

            b. primer

            c. ATP

            d. UTP

            c. CTP





Draw and label a diagram of DNA replication, transcription and translation.


What were the contributions of the following?



Beadle & Tatum

Avery & MacLoed


Watson & Crick

Hershey & Chase








1.         E

2.         B

3.         B

4.         A

5.         B

6.         E

7.         B

8.         C

9.         A

10.       C

11.       B

12.       D