4.2. Cell Cycle & Mitosis

Question 1

Interphase

Answer 1

1. Consists of Gap 1 (G1), the stage of DNA synthesis (S phase) & Gap 2 (G2)
2. Longest component of cell cycle
   - mitosis (1 hour)
   - interphase (+- 23 hours)

Question 2

G1 (Gap 1)

Answer 2

1. Cellular growth
2. The cell conducts its regular metabolic activities
3. The signal committing the cell to replicate is received here
4. If cell division is not signaled, the cell enters quiescent, non-proliferating, resting G0 phase

Question 3

S (synthesis)

Answer 3

DNA replication occurs on every chromosome to produce two sister chromatids

Question 4

G2 (Gap 2)

Answer 4

1. The cell continues to grow and produce proteins

2. Centrioles replicate G1-G2 phase

Question 5

M (mitosis)

Answer 5

1. Two coupled processes:
   - mitosis: chromosomes of cell are divided between two daughter cells
   - cytokinesis: cytoplasm of cel divides

Question 6

Interphase =

Answer 6

G1 + S + G2

Question 7

Restriction point

Answer 7

Point at which cell determines if it has everything it needs to progress further
-> once cell cycle started = complete or die
(I.e. hunger games)

Question 8

Growth factors

Answer 8

1. Enable cells to pass the restriction point and enter S phase
   - > once having passed the restriction point they are committed to proceed through the cell cycle
2. If appropriate growth factors are not available in G1, the cycle stops at the restriction point; the cells enter G0