Flashcards in Mitosis and the Cell Cycle LO Deck (48)
what is the point of the restriction point (R)?
cell must be large enough to move to the next stage (S)
What happens once the cell passes the R phase?
cell is committed to cell cycle
what is the main goal of somatic cell cycle?
ensure exact duplication of genome in S phase followed by exact division of genome in M phase to produce identical daughter cells
how is regulation accomplished throughout the cell cycle?
variation in cyclin concentrations regulate activation of CDKs which in turn regulate formation of pre-replication complex (pre-RC)
what is the level of CDK at start of G1?
low to allow formation of pre-replication complex (pre-RC)
what is level of CDK activity at S?
high, allows activation of pre-RC
what does high CDK activity do to pre-RC formation?
what is the level of CDK in M phase?
high, to allow for cell replication
what does chromosome re-replication complexes in S phase or mis-segregation during mitosis produce?
cancer and birth defects
what is aneuploidy?
incorrect number of chromosomes in a cell
what is the difference between mitosis and meiosis in regards to the numbers and types of cells created?
mitosis = 2 identical diploid cells
meiosis = 4 non-identical haploid cells
what are the 6 phases of mitosis?
what occurs during interphase?
what occurs during prophase?
what occurs during metaphase?
chromosome line up at metaphase plate
what occurs during anaphase
sister chromatids separate and are pulled to opposite ends of cell
what occurs during telophase?
new nuclear membrane surrounds each sister chromatid
what occurs during cytokinesis?
cell divides into 2 diploid cells
what occurs in meiotic prophase?
chromosomes replicate resulting in 2 homologous chromosomes
when does crossing over take place?
during meiotic prophase when sister chromatids are formed
what occurs during meiosis I?
homologs are separated into 2 cells (reductional division)
what occurs during meiosis II?
each pair of sister chromatids separated into different cells resulting in 4 haploid cells (equational division)
what types of cells are stuck in the R point of the cell cycle?
neurons, and then continue to grow without entering the cell cycle
what is a CDK?
what are CDK's activated by?
what are CDK's inhibited by?
Cip/Kip or Ink4 classes of CDK inhibitors
what are 4 common cell cycle regulators that are commonly associated with cancer?
1. retinoblastoma protein (rb)
2. p21 or p16
4. CDK's and cyclins
what is the function of retinoblastoma protein (Rb) and what is result of mutation?
cell cycle inhibitor, loss of Rb leads to tumors
what is the function of p21 or p16?
Cip.Kip and Ink4 CDK inhibitors respectively (loss of them results in cancer)