Quiz Questions

Question 1

In a culture of asynchonously cycling cells, the DNA binding dye Hoechst 33342 is added and the proportion of cells in the phases of the cell cycle are measured. The proportions of cells are 75% in G1, 11% in S phase and 14% in G2/M phase. In contrast, if the same cells are subject to prior treatment with drug X, the proportion of cells in the phases are 88% in G1, 4% in S phase and 8% in G2/M phase.
Which proteins could be inhibited by drug X?

Answer 1

Cdk4 or Cyclin D

Question 2

Kinetochores signal their attachment to the mitotic spindle and release of the spindle checkpoint via interactions between which 2 proteins?

• SKP2/Cdh1
• SKP2/Cdc20
• Mad2/Cdc20
• Mad2/Cdh1

Answer 2

Mad2/Cdc20

Question 3

Mitogens act via their cognate receptor tyrosine kinases to activate kinase signalling pathways resulting in:

• Cdk4 gene transcription
• P21 gene transcription
• Cyclin B gene transcription
• Cyclin D gene transcription

Answer 3

Cyclin D gene transcription

Question 4

Cyclin A-Cdk2 activation inhibits relicensing of replication origins in S-phase via:

• Cdc20 phosphorylation
• Cdc6 ubiquitylation
• Cdc25 phosphorylation
• Cdc6 phosphorylation

Answer 4

Cdc6 phosphorylation

Question 5

Transition from the metaphase to anaphase requires the activity of the APC/C complex to polyubiquitylate which protein?

Answer 5

Securin

Question 6

Transition from the metaphase to anaphase requires the activity of the APC/C complex to polyubiquitylate:

• Separase
• Cohesin
• Condensin
• Securin

Answer 6

Securin