10.1

Question 1

Cell Cycle (in order)

Answer 1

G1
- Grows and prepares for S phase
- Goes to G0 if resources are insufficient or DNA is unhealthy

S
- Replicates DNA

G2
- Continues growing
- Prepares for division

M
- Divides cell into two daughter cells, both with the same number of chromosomes

Question 2

Stimulatory and inhibitory proteins

Answer 2

Stimulatory (cdks, cyclin, growth factors)
- Can pass a cell to the next phase of the cell cycle at a checkpoint if it meets a criteria.

Inhibitory (p53)
- Can stop a cell from moving to the next phase of the cell cycle also at a checkpoint

Question 3

Proto-oncogens and tumor suppressor genes

Answer 3

Proto-oncogens
- Code for stimulating proteins (cyclin, cdks, etc.)
- Becomes an oncogene when mutated
- Can cause cancer if permanently active.

Tumor suppressor genes
- Code for inhibitory proteins (p53, etc.)
- Can cause cancer if both genes are inactive.

Question 4

Why do these things lead to cancer?

Answer 4

Oncogens
- If active forever, it could cause unwanted division and can cause tumors/cancer

Tumor suppressor genes
- If both are inactive, it could also cause unwanted division since there won’t be anything to stop cells through the cell cycle.