Topic 2 - Cell Death

Question 1

What is apoptosis?

Answer 1

Apoptosis is a programmed cell death that prevents damage to neighboring cells by controlling how the affected cell dies.

Question 2

Why do cells undergo apoptosis?

Answer 2

1. to remove damaged or malfunctioning cells
2. to regulate cell population size during development
3. to eliminate potentially harmful cells (such as infectious or cancerous cells)

Question 3

What is cell necrosis?

Answer 3

Necrosis is a traumatic cell death (unpredictable) that causes cell bursting, damaging neighbouring cells by spilling all the intracellular contents.
- it causes inflammation and further trauma.

Question 4

Examples of when a cell will undergo apoptosis

Answer 4

1. DNA damage - it is beyond repair such as from radiation or chemicals
2. Viral Infection - where the infected cell sacrifices itself to prevent the spread of the virus.
3. Developmental processes, like the removal of webbing between fingers during the embryonic development

Question 5

List the steps in apoptosis

Answer 5

1. The cell is separated from neighbouring cells and is signalled to start the process of apoptosis.
2. The cell shrinks, and contents condense.
3. The breakdown of organelles and nucleus is controlled by enzymes called caspases (death enzymes)
4. Blebbing of the plasma membrane
5. Then the budding off of vesicles (blebs) called apoptotic bodies
6. These apoptotic bodies are eaten by WBC called macrophages (no inflammation occurs)

Question 6

How does apoptosis not get inflammation?

Answer 6

1. the contents of the cell are broken down, causing bulges in the membrane, called blebbing. These blebs can separate from the cell, taking a portion of cytoplasms with them. Other cells consume these fragments.
   - keeps damaged cellular contents from spilling out and damaging other cells.

Question 7

What happens when apoptosis does not occur as it should?

Answer 7

Example: Cancer Cells cause unregulated and abnormal cell growth and division. It can be caused by genetic mutations in the cells which leads to an increase in the rate of cell division OR results in the suppression of apoptosis.

Question 8

Why do healthy cells undergo apoptosis?

Answer 8

1. To remove damaged cells
2. Cells that are no longer required by the body for normal growth

Question 9

The cellular enzymes that are involved in the process of apoptosis are known as

Answer 9

caspases

Question 10

Apoptosis is not an important mechanism in

Answer 10

the growth of cancerous tumours

Question 11

A disruption to the checkpoints and the cell cycle can result in

Answer 11

cancer

Question 12

Malfunctions in Apoptosis - Excessive apoptosis

Answer 12

causes a decrease in brain volume due to an excessive loss of neurons.
- causes neurodegenerative diseases

Question 13

Malfunctions in Apoptosis - Inhibited Apoptosis

Answer 13

when apoptosis fails to occur during embryonic development

Question 14

Malfunctions in Apoptosis - Cancer

Answer 14

• Unregulated and abnormal cell growth and division
• genetic mutations lead to an increase in the rate of ell division or result in the suppression of apoptosis.