It is programmed cell death and is an essential part of the development of all animals.
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What is an example of metamorphosis?
Tadpoles changing into frogs- it is a major change in the structure of an organism.
2 of 10
Give an example of apoptosis in frogs.
The tail of the tadpole is lost because the cells in it die and are tidied up by phagocytic cells which engulf and digest them.
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How many mitotic divisions should a cell go through?
About 50 divisions, then it will undergo a series of biochemical events, leading to a tidy cell death.
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Describe the sequence of events in apoptosis.
Enzymes break down cell cytoskeleton. Cytoplasm becomes dense. Cell surface membrane changes & small bits called blebs form. Chromatin condenses & nuclear envelope breaks. DNA breaks into fragments. Cell breaks into vesicles taken up by phagocytosis.
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What is an ineffective T-lymphocyte?
A T-lymphocyte that would not be able to recognise harmful antigens.
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What is a harmful T-lymphocyte?
A T-lymphocyte that attacks own body cells- autoimmune response.
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How is aptosis controlled?
It's controlled by a range of cell signals including cytokines, hormones, growth factors and nitric oxide.
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How does nitric oxide cause apoptosis?
By making inner mitochondrial membranes more permeable to H+ ions, reducing the H+ gradient across these membranes. Gradient is needed for chemiosmosis to occur to generate ATP. Less ATP means cells can't carry out essential metabolic processes die.
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Why should the rate of cells dying balance the rate of cells produced by mitosis?
Not enough apoptosis leads to the formation of tumours, whereas too much leads to cell loss and degeneration.
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Other cards in this set
Card 2
Front
What is an example of metamorphosis?
Back
Tadpoles changing into frogs- it is a major change in the structure of an organism.
Card 3
Front
Give an example of apoptosis in frogs.
Back
Card 4
Front
How many mitotic divisions should a cell go through?
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