mitosis Flashcards
what are the main 2 processes of the cell cycle
mitotic phase
interphase
what are 3 stages of interphase
G1
S phase
G2
what happens at G1 (4 ways)
organelles replicate
transcription/translation
size of cell increases
why is transcription and translation needed in G1
proteins are needed for replication
what happens at G1 checkpoint
growth in size
check for DNA damage
what happens at the S phase (1 way)
chromosomes are replicated
what happens at G0
when cells exit the cell cycle
why would a cell enter G0
DNA damaged (senescent cell)
what happens G2 (3 ways)
transcription/ translation
chromosome repair
increased size of the cell (cell growth)
energy stores replaced
why can’t we see chromosomes in the interphase
they are not compressed at this point of the cell cycle,in the form of chromatin DNA is wrapped around histone proteins
why is chromatin in the interphase not visible
less condensed
what are the 4 stages of mitosis
prophase
metophase
anophase
telophase
what happens at prophase
chromosomes condense
nucleolus disappears
nuclear membrane breaks down
centrioles move to each pole
what happens at the metophase
spindle fibres has formed
chromosome at equator
what happens at the anophase
centromeres divide in 2
spindle fibres shorten (sister chromatids pulled to opposite ends)
what happens at the telophase
chromotids now referred as chromosomes
spindle appartus breaks down
nuclear membrane reform
nucleolus appears
chromosomes uncoil to chromatin
what is cytokinesis
divides the whole cell in 2
what happens at cytokinesis (steps)
central cell membrane pulled in by cytoskeleton
membranes use to form 2 cells
cytoplasm spilt
give 2 ways mitosis is different in plant cells
centrioles don’t play a role in spindle fibres as there is no centrioles present in plant cells
vesicles from Golgi form the membrane structure not the cytoskeleton
what is the equation for the mitotic index
cells in mitosis/total number of cells
what are the 3 things that happen in interphase
cell growth
replication of chromosome
prepares for cell division
describe the products of mitosis
2 identical daughter cells from a single parent cell
state 2 ways in why humans need to mitosis
growth
cell repair
what is a diploid cell
2 complete sets of cells
is a sex cell haploid or diploid
haploid
Explain why the DNA in two sister chromatids are identical
Semi conservative replication
Each DNA strands acts as a template
