Term
| why do we need the cell cycle |
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Definition
| essential for propagation, replacement of dead cells, and increasing specific cell types |
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Term
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Definition
cellular contents, excluding the chromosomes, are duplicated
increase protein synthesis, energy production and cell size |
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Term
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Definition
each of the 46 chromosomes is duplicated by the cell
duplication of 2.9 billion bp |
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Term
| what happens in G2 phase? |
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Definition
| The cell "double checks" the duplicated chromosomes for error, making any needed repairs |
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Term
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Definition
they control the cell cycle by acting on G1 phase, interact with signaling pathways including the GTPase Ras (prenylation) --> MAP kinase cascade and induces gene regulatory proteins (like Myc) --> increased expression of cyclin Ds, which activates G1-Cdk
also delayed response genes which are involved with late G1 progression |
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Term
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Definition
| (cyclin A) promotes formation of preinitiation complexes through phosphorylation, chromosomes are being copied |
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Term
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Definition
| a complex with 4 subunits, keep duplicated chromosomes from S phase tightly bound as sister chromatids, breakdown of cohensins occurs late i n mitosis (early anaphase) |
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Term
| What do negative regulators do? |
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Definition
they regulate the positive regulators and inhibit them (p27 inhibits cycling-Cdk complex)
p27 is a cyclin dependent kinase inhibitor (CDK inhibitor) |
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Term
| Transcriptional repressors |
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Definition
| inhibit cyclin transcription (regulatory) |
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Term
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Definition
| (CDKs) activity, and thus phosphorylation of intracellular proteins, rises and falls during cycle (Paul Nurse) |
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Term
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Definition
| important regulators of CDKs that undergo cycle of synthesis and degradation |
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Term
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Definition
when they bind to cyclin and are phosphorylated by cdk-activating kinase and dephosphorylated by Cdc25 phosphatase
they can then phosphorylate intracellular proteins, pushing the cell along the cell cycle |
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Term
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Definition
Do(promotes passage through G1)G1-cDK
Evenly (commits cell to S) G1/S-CDK
Advance (stimulates Chr. dup.) S-CDK
Bitch (stimulates entry into M) M-CDK |
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Term
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Definition
promotes mitotic progression (M-CDK) activation of CDK1 involves dephosphorylation of CDK1 by Cdc25
active CDK1 is involved in a positive amplification loop |
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Term
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Definition
| helps assemble mitotic spindle, breakdown of nuclear envelope, and promotes arrangement of actin cytoskeleton and chromosomes condensation |
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Term
| Regulation of CDK activity |
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Definition
Inhibitory phosphorylation
Inhibitory protein (p27)
Cyclin degradation
Make no cyclin |
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Term
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Definition
they control cell cycle progression
Scf (degradation of inhibitor)and APC/C (degradation of M-cyclin) - put on the ubiquitin onto proteins for protein degradation
SCF (Rbx1 or 52) catalytic part will actually ubiquinate proteins and Variable component (F-box) will recognize phosphorylated proteins for ubiquination and degradation |
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Term
| APC (chromatid separation) |
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Definition
is a ubiquitin ligase that targets securin (an inhibitor of separase) for degradation, separase can now go and cleave cohesin and sister chromatids can separate
Cdc20 activates APC |
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Term
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Definition
G1/S phase - is the environment favorable (enough glucose for replication)
G2/M - is environment favorable, is there any problems?
M-to-A transition - is everything aligned correctly |
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Term
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Definition
activates ATM/ATR kinase, which associate with Chk1/Chk2 at site of injury
can phosphorylate p52 and stabilize it so that it can upregulate the CK1 p221 to arrest in G1
Chk1 can phosphorylate and thereby inactivate Cdc25, resulting in the increase of inhibitory phosphorylation on CDK1 to arrest in G2/M |
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Term
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Definition
pRb-protein retinoblastoma - important at G1/S checkpoint- normally E2F is bount to pRb and is an inhibitor and bound to HDAC, phosphorylation causes pRB to release HDAC and fully activate EF2 (which will push the cell into S phase)
caused by loss of Rb protein |
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