Biology Chapter 12.3: Cell Cycle Regulation and Cancer Cells – Flashcards
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what does the cell cycle appear to be driven by?
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specific chemical signals present in the cytoplasm
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what are the sequential events of the cell cycle directed by?
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A Cell cycle control system
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what is the cell cycle control system regulated by?
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Both internal and external controls
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what do checkpoints in the cell cycle do?
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these checkpoints are where the cell cycle stops until a go-ahead signal is received
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what happens if a cell receives a go-ahead signal at the G1 checkpoint?
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it will usually complete the S, G2, and M phases and divide
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what happens if the cell does NOT receive the go-ahead signal at the G1 checkpoint?
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it will exit the cycle, switching into the G0 phase.
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what is the G0 phase?
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a nondividing state, where the cell goes when it doesn't receive the go-ahead signal
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which two types of regulatory proteins are involved in cell cycle control?
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cyclins and cyclin-dependent kinases (Cdks)
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what does the CDKs activity fluctuate?
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because it is controlled by cyclins. cyclins, concentrations vary with the cell cycle
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What is MPF?
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(maturation-promoting factor) -A cyclin-Cdk complex that triggers a cell's passage past the G2 checkpoint into the M phase
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what is an example of an internal signal?
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kinetochores not attached to spindle microtubules send a molecular signal that delays anaphase
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what are some external signals?
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growth factor proteins
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What are released by certain cells that stimulate other cells to divide?
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Growth Factor Proteins
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what does the PDGF (platelet- derived growth factor) do?
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stimulates the division of human fibroblast cells in culture
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what is a clear example of external signals?
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density-dependent inhibition
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what is density-dependent inhibition?
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in which crowded cells stop dividing
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what do most animal cells exhibit?
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anchorage dependence
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what is anchorage dependence?
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in which they must be attached to a substratum in order to divide
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do cancer cells exhibit density-dependent inhibition or anchorage dependence, like a healthy cell?
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no, they're rebels!!
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do cancer cells respond normally to the body's control mechanisms?
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no
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do cancer cells eed growth factors to grow and divide?
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no
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what do cancers create, to grow and divide?
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growth factors
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what type of cells have an abnormal cell cycle control system?
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cancer cells
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what process converts a normal cell into a cancerous cell?
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transformation
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what do they call the lump, at the original site?
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a benign tumor
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what are benign tumors?
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-tumors that do not grow in an unlimited, aggressive manner -doesn't invade surrounding tissues -nor metastasize
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what do malignant tumors do?
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invade surrounding tissues and metastasize
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what is metastasize?
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exporting cancer cells to other parts of the body
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if a parent cell has 10 chromosomes, how many chromosomes will be in each daughter cell?
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10 chromosomes
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in which stage are chromosomes replicated?
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S of interphase
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what is the purpose of mitosis?
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produce new offspring
