Term
| cell replication requires (2) |
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Definition
| duplication of cellular contents, division into two cells |
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Term
| limiting facto in prokaryotes |
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Definition
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Term
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Definition
| most variable duration. cell contents double (but DNA doubles in S phase) |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| quiescence from which cells can reenter G1 |
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Term
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Definition
| terminal diff or senescence |
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Term
| typical human cell cycle time |
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Definition
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Term
| components of cell cycle machinery (3) |
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Definition
| cyclins, cyclin-dependent kinases, cyclin-dependent kinase inhibitors |
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Term
| how are cdk's activated and what do they do |
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Definition
| activated when cyclin binds; cdks phosphorylate other things |
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Term
| cyclin D's cdks and site of action |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
| t/f the expression of cyclins in the D family is uniform throughout cell types |
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Definition
| false - hepatocytes and B/T cells are different |
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Term
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Definition
| are cyclical and therefore regulate cdk activity (cdks have constant protein levels) |
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Term
| what kind of kinases are cdks |
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Definition
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Term
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Definition
| key regulator of cell cycle progression and other cell processes - apoptosis, differentiation. binds to cyclin/cdk complex, which inhibits cdk activity |
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Term
| 2 main classes of CKIs and basic stuff |
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Definition
| INK and KIP. INK is only ever active in G1. |
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Term
| clinically relevant CKIs (2) |
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Definition
| p21 (KIP) - induced in response to DNA damage. p16 (INK) - mutated in many human tumors. |
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Term
| formation of active cyclin/cdk complexes requires (4) |
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Definition
| adequate cyclin levels, cdk presence, CKI at sufficient but low level, ability of CAK or other kinase to phosphorylate the complex while suppressing the relevant phosphatase |
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Term
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Definition
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Term
| cdk activity is regulated by (3) |
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Definition
| cyclin content, cki content, phosphorylation status |
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Term
| cyclin content is regulated at the level of (3) |
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Definition
| transcription, translation, protein degradation |
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Term
| CKI content is regulated at the level of (3) |
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Definition
| transcription and protein degradation only |
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Term
| control of cki cdk and cyclin is downstream from (2) |
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Definition
| growth factor signaling pathways and intrinsic regulatory cell mechanisms |
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Term
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Definition
| separates g1 phase; 1st = requires continuous mitogenic signals and a high rate of protein synthesis. interruption of this phase leads to quiescence (G0). once the cell passes through restriction point it becomes committed to DNA synthesis and cell division. |
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Term
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Definition
| retinoblastoma protein, regulates partially the restriction point. is a focal point for malignancy in newborns. |
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Term
| before G1 restriction point, Rb |
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Definition
| is hypophosphorylated and bound to transcription factor E2F, which inactivates E2F. |
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Term
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Definition
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Term
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Definition
| external signals like growth factors and integrins > MYC, RAS and other genes > cyclin D > active D/cdk4 complex *> Rb phosphorylation > active E2F >>> cell cycle. *: inhibited by p16 and p21, so if either of those is mutated, you probably get cancer. |
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Term
| terminally differentiated cells examples? (2) |
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Definition
| neurons, skeletal muscle cells |
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Term
| cells that proliferate when needed examples (2) |
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Definition
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Term
| how is senescence different from term. diff. |
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Definition
| senescence is due to lack of nutrients, term. is due to need of those cells |
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Term
| overexpression of D and E (3) |
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Definition
| breast and testicular cancer, leukemia |
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Term
| Rb mutational inactivation (3) |
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Definition
| osteosarcomas, small cell lung carcinomas, Rb |
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Term
| cervical cancer - specific protein |
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Definition
| sequestration of Rb by HPV E7 protein |
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Term
| deletion or mutation of CKI genes |
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Definition
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Term
| regulation of cell growth: c-Myc and MTOR. |
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Definition
| c-Myc (proto-oncogene) > when expressed, activates RNA Pol I > synthesizes rRNA > ribosomes synthesized > size is best correlated with ribosome number > cell doubles its size to pass into S phase. MTOR (nutrient-sensing kinase) activates 5'TOP transcription > ribosomal proteins > ribosomes > lots = size > doubled size |
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Term
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Definition
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Term
| cancer cells often demonstrate _ of cell size |
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Definition
| dysregulation = they're smaller |
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Term
| pathways to regulate synthesis of _ differ in cancer cells |
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Definition
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Term
| how does cancer just keep growing? |
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Definition
| arteries grow with it to provide nutrients, but the middles of tumors often necrose anyway |
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Term
| how do we define growth? (2) |
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Definition
| hypertrophy = cell growth, proliferation = requires cell growth |
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Term
| what causes cells to proliferate and hypertrophy in bone? |
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Definition
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Term
| replicative senescence and final height |
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Definition
| there is a limit to the number of times cells in resting zone of bones can divide. timing differs between individuals. once cells in resting zone are no longer proliferating, growth plate closes |
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Term
| is there a hormone that regulates senescence in the resting zone of bones? |
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Definition
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Term
| what is greater in bigger people: proliferation or hypertrophy? what does a null mutation of IGF system cause? |
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Definition
| proliferation, which depends upon hypertrophy. mutation causes decreased cell number |
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Term
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Definition
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Term
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Definition
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Term
| IGF-I block and IGF-II block |
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Definition
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Term
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Definition
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Term
| what kind of diet promotes longer life, and why? |
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Definition
| low protein, low calory. because IGF-I is not as activated. mechanism unknown, but the smaller you are, the longer you live. |
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Term
| 15-megabase region on chromosome 15 (IGF1) |
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Definition
| gene region for size determination in dogs |
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Term
| what is present in small dogs but not big dogs |
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Definition
| a single-nucleotide polymorphism haplotype |
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Term
| 3 main things that don't happen if people eat less |
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Definition
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