cell division Flashcards
cell division
nuclear division followed by cytoplasmic division
another name for nuclear division
karyokinesis
another name for cytoplasmic division
cytokineses
diploid cells have 2 copies of every chromosome forming…
homologous chromosomes
how many chromosomes do humans have
46
(23 homologous pairs)
animal cells have cellular structures called
centrosomes
each centrosome contains a pair of
centrioles
centrioles produce
spindle fibers that will separate sister chromatids during anaphase
the cell cycle is divided into
interphase (G1, S, G2)
mitotic phase (mitosis + cytokinesis)
interphase
begins after mitosis and cytokinesis are complete
(when cells are replicated and physically separated
G1
cell increases in size
G1 checkpoint ensures everything is ready for DNA synthesis
most cell growth in volume occurs here
S
DNA synthesis
second molecule of DNA replicated from the first creating sister chromatids
when is DNA replicated
S phase
NOT mitosis
G2
rapid cell growth continues to occur
preparation of genetic material for cellular division
cell replicates organelles
G0
inactive state of cells not actively growing or dividing
what cells are examples of G0 (2)
nerve cells
cardiac cells
surface area to vol ratio
SMALL
cellular exchange is hard
leads to cell death or cell division to increase surface area
Genome to volume ratio
SMALL
as the ratio decreases the cell exceeds the ability of its genome to produce proteins needed to regulate the cell
spindle apparatus forms when
during prophase
what are crucial to cell division during mitotic phase
microtubules
mitotic spindle
what do anti-tumor drugs act on in cancers?
act as microtubule inhibitors
the drugs stabilize microtubules preventing chromosome and chromatid separation and causing cell cycle arrest (no cell division)
when does a virus impact the mitotic spindle
impacts the spindle most affects a cell during mitotic phase
each sister chromatid has a
kinetochore
where microtubules attach - not chromosomes directly
MITOSIS
prophase - chromosome and chromatids
46 chromosomes
92 chromatids
MITOSIS
prophase
nucleus disassembles
nucleolus disappears
chromatin condenses into chromosomes
MITOSIS
metaphase - chromosomes + chromatids
46 chromosomes
92 chromatids
MITOSIS
metaphase
chromosomes line up
each metaphase chromosome consists of 2 attached sister chromatids
each chromatid is complete with a centromere and attached kinetochore
MITOSIS
Anaphase - chromosomes + chromatids
92 chromosomes
92 chromatids
MITOSIS
Anaphase
microtubules shorten and each chromosome is pulled apart into 2 separate chromatids (once physically separated, each chromatid is considered a chromosome so the chromosome # has doubled)
chromosomes pulled to opposite poles
each pole has a complete set of chromosomes