Apoptosis

Question 1

Apoptosis

Answer 1

or programmed cell death (PCD) is a natural method of destroying cells that are no longer required

Question 2

2 process of apoptosis

Answer 2

intrinsic and extrinsic

Question 3

Intrinsic pathway

Answer 3

initiated by internal signals, often due to cellular stress or DNA damage. Mitochondria releases cytochrome C and then the caspase enzymes are activated, which destroy cell contents

Question 4

Extrinsic pathway

Answer 4

A mistake in cell which is recognised by immune cell. Death signalling molecules are released and recognised by cell receptors. The caspase is then activated and then destroys cell contents

Question 5

After activation of caspases

Answer 5

The mitochondria detects internal DNA damage and releases cytochrome C. The caspase cleave intracellular proteins, which leads to the breakdown of organelles. The cell and nucleus shrink as intracellular material is broken down. As the cytoskeleton is digested, the structural integrity of the cell is weakened. The membrane wraps and detaches from the apoptotic bodies which contain the broken down intracellular material

Question 6

When apoptosis goes wrong

Answer 6

when mistakes occur and the mistake is replicated, groups or clusters of cells with mistakes can form tumors (cancer)

Question 7

Necrosis

Answer 7

uncontrolled, often due to injury, causing cell swelling, membrane rupture and inflammation. Doesn’t involve caspase.