6.1 QR cell cycle

Question 1

What is interphase? What stages does it consist of?

Answer 1

Growth period, G1, S, G2

Question 2

What happens during interphase? 5 points

Answer 2

1. DNA replicated + checked for errors
2. Protein synthesis
3. Mitochondria grow + divide
4. In plants, chloroplasts grow + divide
5. Normal metabolic processes of cell occur

Question 3

What happens during G1?

Answer 3

1st growth phase: proteins from which organelles are made are produced + organelles replicate. Cell increases in size

Question 4

What happens during S?

Answer 4

Synthesis: DNA is replicated in nucleus

Question 5

What happens during G2?

Answer 5

2nd growth phase: Cell increases in size, energy stores increased, DNA checked for errors

Question 6

What are the final 2 stages of the cell cycle? Define

them

Answer 6

Mitosis - nucleus divides

Cytokinesis - cytoplasm divides into 2 cells

Question 7

What is the G0 phase?

Answer 7

When a cell temporarily/permanently leaves the cell

cycle

Question 8

What are the 2 reasons for why a cell might leave the cell cycle?

Answer 8

1. Differentiation - cell becomes specialised so never returns into cell cycle
2. DNA is damaged and enters permanent cell arrest
   (G0)

Question 9

Explain the G1 checkpoint. What does it check for?

Answer 9

Checks for: cell size, nutrients, growth factors, DNA damage

If cell has errors, it enters G0 before S

Question 10

What is checked at the G2 checkpoint?

Answer 10

Cell size, DNA replication, DNA damage

Question 11

What does the spindle assembly checkpoint check for?

Answer 11

Chromosome attachment to spindles