Cell cycle

Question 1

Describe interphase

Answer 1

main part of cell cycle
1. G1 phase
- Cell increases in size
- Ribosomes, RNA produced
- Preparation for DNA synthesis
2. S phase
- DNA synthesised (chromosomes duplicated)
3. G2 phase
- Cell check fidelity of DNA
- Prep for nuclear division

Question 2

Describe what happens in G1 phase of interphase

Answer 2

• Cell increases in size
• Ribosomes, RNA produced
• Preparation for DNA synthesis
• performs normal functions

Question 3

Describe what happens in S phase of interphase

Answer 3

DNA synthesised (chromosomes duplicated)

Question 4

Describe what happens in G2 phase of interphase

Answer 4

Cell check fidelity of DNA
Prep for nuclear division

Question 5

List the sub-phases of mitosis

Answer 5

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

Question 6

What drives the transition from G1 to S phase?

Answer 6

External signals, e.g growth factors
- transition happens after around an hour or 2

Question 7

What happens if serum and growth factors are removed from cells yet to complete 80-90% of G1 phase?

Answer 7

Fail to proceed to S phase, revert to G0 phase (no division or growth occurs)

Question 8

What happens if the R-point is deregulated during mitosis?

Answer 8

R-point = regulation point
= formation of most types of cancer cells

Question 9

Describe how early embryonic cells allow us to purify cell cycle regulators

Answer 9

-Take egg cytoplasm, separate out proteins into different classes e.g by size
-Inject back into oocyte and see if it triggers the G2 to M transition

Question 10

What does CDK stand for?

Answer 10

Cyclin-dependent kinases

Question 11

Which type of enzyme controls the cell cycle transition

Answer 11

Protein kinase

Question 12

Cell cycle transitions involve the irreversible destruction of _____

Answer 12

cyclins

Question 13

When are CDKs inactive?

Answer 13

When the cyclin is removed