Chapter 1.4 - Apoptosis Flashcards
What is cell necrosis?
The unexpected or improper death of cells caused by external factors which the cells do not influence, such as pathogens or trauma. It is harmful and can be fatal
What is apoptosis?
It is the programmes cell death of a cell. It is a tidy and clean death which causes no harm to the overall organism.
How many mitotic cell divisions sub a cell undergo before apoptosis?
50
Outline the stages of apoptosis in order.
1) enzymes break down the cells cytoskeleton.
2) the cytoplasm becomes densely packed as all the tiny organelles bundle together.
3) the cell surface membrane alters in shape giving the appearance of a flaccid cell with many blebs.
4) chromatin from within the nucleus condenses and the nuclear envelope breaks down.
5) as the nuclear envelope breaks down, DNA also breaks into fragments and nuclear fragments become separated into smaller chunks that will be split into smaller vesicles.
6) the cell packages it’s contents into vesicles.
7) vesicles are taken up by phagocytes and the cellular debris is disposed of, and by this apoptotic method no other cells are harmed.
Is apoptosis a fast or slow process?
Fast
What is apoptosis controlled by?
A range of cellular signals, both intracellular and extra cellular. These signals include cytokines made by cells in the immune system , hormones and nitric oxide.
How does nitric oxide bring about apoptosis?
Nitric oxide induces apoptosis by making the mitochondrial membrane more permeable to hydrogen ions, removing the carefully maintained concentration gradient that drives chemiosmosis.
What kind of cells do not go under apoptosis?
Cells with damaged DNA, including a mutation to genes involved in regulating mitosis.
How is a tumour formed
Cells with mutated DNA do not go under apoptosis so keep on replicating my mitosis meaning a tumour is formed.
What causes webbed feet?
Improper apoptosis
How can the body prevent tumours?
Balance the rate of mitosis and apoptosis.
