Cell Division Flashcards
how many chromosomes in humans?
46 chromosomes (23 homologous pairs)
what does a centrosome contain?
pair of centrioles
centrioles
produce spindle fibers that separate sister chromatids during anaphase
regulation of cell cycle
- surface-volume ratio
- genome-volume ratio
surface-volume ratio
if the volume ratio is small when cell is too big it makes cell exchange hard leading to cell death/division to increases surface area
genome-volume ratio
if it decreases, the cell exceeds ability of its genome to produce proteins needed to regulate the cell
cell cycle
interphases consiting of G1, S, G2 phase
when does interphase occur?
after mitosis and cytokinesis
G1
cell increases in size and G1 checkpoint ensures everything is ready for DNA synthesis
where does most cell growth occur?
G1 phase
S phase
DNA synthesis; 2nd molecule of DNA replicated from 1st into sister chromatids
where is DNA replicated?
S phase
G2 phase
rapid cell growth; preparation of genetic material for cell division, cell replicates organelles
G0 phase
inactive state of cells not actively growing/dividing
- nerve and & cardiac cells
when does the spindle apparatus form?
during prophase
what does each sister chromatid have?
kinetochore
where does kinetochore attach
MT attach’ MT don’t directly attach to chromosomes
prophase chromosomes/chromatids
46 chromosomes
92 chormatids
metaphase chromosomes/chromatids
46 chromosomes
92 chromatids
anaphase chromosomes/chromatids
92 chromosomes
92 chromatids