1.        What is the importance of the 3’ to 5’ exonuclease activity of DNA polymerase I during DNA replication?

A.        It removes any nucleotides that it has incorrectly inserted.

B.        It removes any nucleotides that DNA polymerase III has incorrectly inserted.

C.        It removes each RNA nucleotide in the primer and replaces it with a DNA nucleotide.

D.       It removes all the RNA nucleotides in the primer and then replaces them with DNA nucleotides.

2.        How many DNA polymerase III molecules are operating at each replication fork during DNA replication?

A.        1

B.        2

C.        3

D.       4

3.        Which DNA repair mechanism can only be carried out for a short time after DNA replication in

E. coli?

A.        Mismatch repair.

B.        Base excision repair.

C.        Nucleotide excision repair.

D.       Non-homologous end-joining.

4.        Which type of DNA damage is nucleotide excision repair required for?

A.        Depurination.

B.        Pyrimidine dimer.

C.        Deamination of a cytosine.

D.       Double-stranded break.

5.        The image below shows a gene on a chromosome. The start point of transcription is indicated by the thick arrow. The endpoint of transcription is shown by the thin arrow. The black box     represents the promoter sequence. Which strand is the coding strand, and which end is its 5’ end?

A.        Upper strand, to the left.

B.        Upper strand, to the right.

C.        Lower strand, to the left.

D.       Lower strand, to the right.

6.        Which part of RNA polymerase II is central to the regulation of mRNA processing?

A.       The large subunit.

B.       The small subunit.

C.       The N-terminal domain.

D.       The C-terminal domain.

7.        The following sequence is a fragment of an mRNA sequence. Use the genetic code table above to determine the amino acid sequence it encodes.

5’AGGGCUCGGAGUUCU3’

A.        N-Arg-Ala-Arg-Ser-Ser-C

B.        C-Arg-Ala-Arg-Ser-Ser-N

C.        N-Arg-Thr-Pro-Ser-Pro-C

D.       C-Arg-Thr-Pro-Ser-Pro-N

8.        How does the ribosome carry out its catalytic function?

A.       The RNA of the ribosome catalyses peptide bond formation, moving the growing polypeptide from the tRNA in the P site to the tRNA in the A site.

B.       The RNA of the ribosome catalyses peptide bond formation, moving the growing polypeptide from the tRNA in the A site to the tRNA in the P site.

C.       The protein of the ribosome catalyses peptide bond formation, moving the growing polypeptide from the tRNA in the P site to the tRNA in the A site.

D.       The protein of the ribosome catalyses peptide bond formation, moving the growing polypeptide from the tRNA in the A site to the tRNA in the P site.

9.        What regulators of gene expression bind the lac operon if the E. coli is grown in media containing both lactose and glucose?

A.        Both the lacI repressor and the CAP protein bind.

B.       The lacI repressor doesn’t bind but the CAP protein does.

C.       The lacI repressor binds but the CAP protein doesn’t.

D.       Neither the lacI repressor nor the CAP protein bind.

10.     A strain of E. coli has a disruptive mutation in the trpR gene. What is the effect on the expression of the trp operon?

A.       The trp operon is expressed only when tryptophan is present.

B.       The trp operon is expressed only when tryptophan is absent.

C.       The genes in the trp operon are always expressed.

D.       The genes in the trp operon are never expressed.

11.      How do gene regulatory proteins generally bind the DNA?

A.       They bind the phosphate backbone.

B.       They bind the bases in the major groove.

C.       They bind the bases in the minor groove.

D.       They bind the bases by moving aside the base pairing.

12.     What is the effect on gene expression of the acetylation of histones and cytosine methylation of DNA?

A.       They both activate gene expression.

B.       They both inhibit gene expression.

C.       The acetylation of histones activates gene expression and cytosine methylation of DNA inhibits gene expression.

D.       The acetylation of histones inhibits gene expression and cytosine methylation of DNA activates gene expression.

13.     What level of chromatin compaction would an actively transcribing DNA region have?

A.       An area with no proteins.

B.        Nucleosomes only.

C.        Nucleosomes or 30 nm fibre.

D.       30 nm fibre.

14.     Which of the following accurately describes the proportion of DNA making up different features of the human genome?

A.       Coding sequence > introns > centromeres and telomeres > transposons

B.        Coding sequence > transposons > introns > centromeres and telomeres

C.       Transposons > introns > centromeres and telomeres > coding sequence

D.       Transposons > coding sequence > introns > centromeres and telomeres

15.     What sequence in a bacterial plasmid vector is required for it to be recognised by DNA polymerase?

A.       Origin of replication.

B.        Restriction endonuclease sites.

C.       Antibiotic resistance gene.

D.       Bacterial promoter.

16.     To analyse the expression of a gene by looking at the mRNA, which technique would you use?

A.        PCR

B.        RT-PCR

C.        Western blot

D.       SDS-PAGE

17.     What is the role of the p21 protein in cell cycle checkpoints?

A.        It activates CDK2 by phosphorylating it on Thr160

B.        It inactivates CDK2 by phosphorylating it on Tyr15

C.        It attaches ubiquitin to cyclinE to target it for degradation.

D.       It binds to CDK2/cyclinE to inhibit its activity.

18.     As the cell progresses through the cell cycle, the DBRP is phosphorylated and activated by the CDK/cyclin complex until it activates the next phase of the cell cycle. What is the function of   the DBRP?

A.        It activates CDK2 by phosphorylating it on Thr160

B.        It inactivates CDK2 by phosphorylating it on Tyr15

C.        It attaches ubiquitin to cyclinE to target it for degradation.

D.       It binds to CDK2/cyclinE to inhibit its activity.