Biology 2:cells - mitosis Flashcards
explain how chromosomes replicate
chromosomes duplicate forming sister chromosomes
mitosis occurs and two daughter b
what are the 5 stages of cell division
g1 PHASE
s phase
g2 phase
m phase
G0 phase
what are the phases in the interphase(90% of cell cycle)
g1
s phase
g2
what happens in g1
cell increases in size
and produces more proteins to prepare to divide
what happens in the s phase
duplication of dna for division
what happens in g2
cell grows rapidly and synthesises more proteins
checks for any damage in dna
what happens in g0
cell stops dividing once they are fully grown and differentiated
state the stages in mitosis
interphase
prophase
metaphase
anaphase
telophase
what happens in the interphase and prophase
dna duplicates to form sister chromatids
nucleus starts to disintergate and chromosomes condense
what ahppens in the metaphase and anaphae
spindles are formed and chromosomes line up in the middle
chromosomes are pulled apart at centromeres to poles
what happens in telophase and cytokinesis
chromosomes are now at opposite ends
cytoplasm splits to make 2 new daughter cells
where in the cell cycle does checkpoints occur
g1 g2 m(metaphase)
why is there a checkpoint in g2
that dna has been replicated properly in s phase
why is there a checkpoint in mitosis
metaphase checks all chromosomes are lined up
what genes control mitosis
oncogenes
what happens if the oncogenes mutate
cell cycle can run too fast or too slow which results in a ball of genes(tumors)
how does chemotherapy drugs work
interfere with the control of cell cycle by blocking the s phase
or interferes with spindle formation in metaphase
stops tumours form growing uncontrollably
why doesnt bacteria do mitosis(3 reasons why)
doesnt have a separate chromosome and nucleus
doesn’t have loads of chromosomes
so they don’t need to divide carefully
how does binary fission work(5 things)
replicates circular pieces of dna (nucleoid)
replicates plasmids
cell lengthens
cytoplasm divides(cytokenisis)
new cell wall formed where cytoplasm is divided
name 3 reasons why binary fission is different to mitosis
daughter cells are not always genetically identical - because there could be an uneven distribution if organelles
variation in the number of plasmids copied
sometimes nucleoid doesn’t separate properly so only one cell of DNA
What’s the difference betweeen mitosis 1 and mitosis 2
Mitosis one use homologous chromosomes
Mitosis 2 chromatically separate
Mitosis one 2 daughter cells mitosis 2 is 4
