4C: Apoptosis

Question 1

What is apoptosis?

Answer 1

Apoptosis is programmed cell death (that is regulated)

Question 2

What are the two pathways of apoptosis?

Answer 2

1. Intrinsic (mitochondrial pathway)
2. Extrinsic (death receptor pathway)

Question 3

What is the process of the mitochondrial pathway?

Answer 3

1. The mitochondria detects stress inside the cell (can be damage to DNA)
2. The mitochondria released cytochrome C
3. Cytochrome C and cytosolic proteins bind to create an apoptosome
4. Caspases are activated
5. Apoptosis is initiated

Question 4

What is the process of the death receptor pathway?

Answer 4

4. 5.

Question 5

What is a cell death that is not regulated?

Answer 5

Necrosis

Question 6

What are the stages of apoptosis?

Answer 6

1. Cells that are stressed, damaged, or triggered by signal molecules begin apoptosis.
2. Cell starts shrinking and blebbing. Nucleus degrades and the chromatin forms clumps.
3. Nucleus collapses but some organelles are not affected. Cell sends signals to attract macrophages.
4. Nucleus breaks up into spheres, DNA breaks up, and cell fragments.
5. Cell breaks into many apoptotic bodies. Macrophages remove them via phagocytosis.

Question 7

What is blebbing?

Answer 7

Bubble-like projections on the cell membrane

Question 8

What is the purpose of apoptosis?

Answer 8

Ensure normal functioning of an organism
Maintains adult cell numbers
Stops replication of damaged and dangerous cells to prevent tumors

Question 9

How can a decreased rate of apoptosis lead to cancer?

Answer 9

Decreased rate=malfunction of apoptosis.
Uncontrolled growth of defect cells dividing will lead to clump of unwanted cells (tumor).

Question 10

How do cancerous cells form?

Answer 10

Changes in the genes that control normal cell growth and division

Question 11

What are the two genes involved with the cell cycle?

Answer 11

Proto-oncogenes: Start cell division, essential for normal cell development
Tumor-suppressor genes: Switch off cell division