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35 Cards in this Set
- Front
- Back
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what does the process of propagation consist of?
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growth and division
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what is mitosis?
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a process of cell division
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what is interphase?
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the interval of quiet growth between mitoses
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what is the cell cycle?
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progression through mitosos, interphase, mitosis, interphase, etc
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how long is mitosis typically? what is the range?
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24hrs normally
can be 8min-1year |
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which stage of the cycle does the cell spend most of it's time in?
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interphase
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what happens during interphase?
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the cell duplicates organelles, grows, and prepares for division
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what is the S phase?
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when the cell duplicates its chromosomes and synthesizes new DNA
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where is G2?
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after S, before M
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where is G1?
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before S
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where are most of the cell's normal functions carried out?
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G1
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what phase do cells enter when they are no longer actively dividing?
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G-zero
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at which stage is a cell considered "committed" to division?
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once it has entered S phase
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what happens at the G1 checkpoint?
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determines whether of not contidions are right before entering S
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what happens at the G2 checkpoint?
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determines whether DNA, centrioles, etc are duplicated and ready for mitosis
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is there a checkpoint in metaphase?
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yes- to determine whether the chromosomes are lined up on the metaphase plate before entering anaphase
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which checkpoint has been most heavily studied?
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G2
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what is MPF?
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M-phase Promoting Factor
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what are the subunits of MPF?
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CDK (cyclin dependent kinase) and Cyclin
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what is CDK?
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an enzyme that phosphorylates other enzymes or proteins involved in mitosis and thus regulates their activities
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what is cyclin?
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the regulator of CDK
binds to CDK to activate it |
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what are the normal concentrations of CDK and cyclin in the cell?
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CDK- present at concentrations
cyclin- concentrations vary throughout the cycle, peaks at G2 and then drops off |
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how powerful is MPF?
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very... if injected into a cell it will divide even if it not ready to
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how is proliferation regulated?
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by a number of environmental factors including food availability
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what is density-dependent inhibition of cell division?
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when a certin density is reached cells will stop dividing... due to GF's or nutrients not available
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what is cancer?
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uncontrolled cell proliferation that cause an imbalance among an individual's cell population, which can lead to premature death
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in a microenvironment, what is essential for cell division?
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GF's
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what happens if a GF is mutated?
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start dividing without stimulation, divide in excess
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what are oncogenes?
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mutated genes that lead to uncontrolled growth
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what are protooncogenes?
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normal, unmutated versions of oncogenes
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what is the role of oncogenes and protooncogenes?
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involved in stimulating and regulating the cell cycle
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what are growth inhibitory factors?
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factors that act on cells to slow or stop cell division
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what is another name for growth inhibitory factors?
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tumor-supressor genes
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what are tumor supressor genes?
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their products act to stop cell division and thereby supress tumor growth
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what is the result of a mutation of tumor supressor genes?
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wild cell growth or the inability for a cell to replace cells that are lost... depends on the type of mutation
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