cell cycle Flashcards
for every ___ there has to be a previous ___
cell, cell (continuity of life)
if you want to simply divide the big cells you go straight to which phase?
S phase with short/no G phases
what are the stages of the cell cycle?
- M phase: nucleus and cellular contents divide (mitosis and cytokinesis)
- interphase: occurs between the two M phases
- G1 and G2: cell grows and duplicating content (transcription and translation)
- S phase: occurs b/w G1 and G2, DNA replication/synthesis
what will happen if you do not duplicate everything in the cell?
overtime the cell will shrink and ultimately lose its function
what are the 3 important checkpoints?
- G1 to S transition: is the environment favorable?
- G2 to M transition: is DNA replicated, is DNA damage repaired?
- M to G1 transition (mitotic checkpoint): are all chromosomes properly attached to spindle?
________ regulate the cell cycle and is dependent on phosphorylation
cyclin-dependent kinases (Cdk)
_____ are regulated by transcription
cyclins
cyclins are degraded by
ubiquitination (proteasomal degradation)
mitotic Cdk is regulated by
kinases and phosphatases
how do Cdk inhibitors work?
they bind to the whole cyclin Cdk complex rendering it inactive
G1-S phase checkpoint
- mitogen binds to receptor
- binding causes active retinoblastoma to be phosphorylated and becomes inactive
- inactive of Rb causes activation of transcription regulation
- transcription proceeds and cell is proliferated
what holds together the sister chromatids?
cohesin rings holds chromatids together and condensin rings keep chromatids condensed.
describe mitosis
- prophase: chromatin is developed and condensed into two copies
- prometaphase: spindles attach to kinetochore, nuclear envelope broken down
- metaphase: chromosomes aligned at metaphase plate
- anaphase: sister chromatids pulled toward spindle pole
telophase: two sets of chromosomes arrive at spindle poles, new nuclear envelope develops around each set - cytokinesis: cytoplasm is divided into two
