W5 Cell Cycle and Division Flashcards
what happens in prophase
- formation of centrosomes
- chromosomes condense
- mitotic spindles form
what are centromeres made of
centrioles + micro tubules
what happens in prometaphase
chromosomes attach to spindle micro tubules
how do chromosomes attach to spindle micro tubules
kinetochores
what is karyotyping
metaphase
what happens during metaphase
- chromosomes align at equator of spindle poles
- kinetochore micro tubules attach chromatids to opposite spindle poles
what happens during Anaphase
- pulls sister chromatids to spindle poles
- shortens micro tubules
why do kinetochore microtubules shorten?
spindle poles move apart
what happens during telophase
- chromosomes move to spindle poles to decondese
- nuclear envelope reforms
what is the end result of Mitosis
forms two identical daughter nuclei
what is binary fission and how does it work
- unicellular mitosis
- cell elongation and DNA rep
- cross wall formation
- clone cells
what are CDC mutants
- cell division cycle genes
- temperature sensitive
what happens if CDC are mutated
cell cycle arrest
what is cyclin
regulates cell cycle
how is CDK complex formed
cyclin + inactive CDK
whats the role of thymosin
binds to actin to prevent actin filaments
whats the role of profilin
speeds up the binding of actin
whats the role of formins
promote the filament elongation
what are the role of integrin receptors
link cells to extracellular matrix
whats the role of cadherins
link cells to other cells
what are adheren junctions
links to F-actin filaments
is mitosis diploid or haploid
diploid
what does diploid mean
2 genetically identical daughter cells
what happens in G1 phase
check and repair DNA
synthesise RNA + proteins
increase cell size
what happens in G0 phase
resting
what happens in S phase
chromosome and centrosome dupe
what is the roles of cohesins
hold sister chromatids together
DNA repair and gene expression
what shape do cohesins form
ring structure
what does cohesin do when metaphase anaphase transition
cleavage of sister chromatids
what enzyme removes cohesin complexes
seperase enzyme
what’s the role of G2 phase
prepare for mitosis
microtubule synthesis
what’s the role of M phase
divide + nucleus + cytoplasm
condense chromosome and spindle form
what happens when M phase and G1 fuses
immediately enters mitosis
what are the role of CDKs
bind to cyclins to regulate cell cycle
what are CDKS and cyclins degraded by
APC
what does p53 do when switched on
stops cell division
how is p53 pathway activated
UV light or ionizing radiation causing DNA damage
what’s the role of MPF
stimulate transition of G2 to M phase
why are cyclins and CDKs degraded
to move out of M phase
what can prevent phase transitions
DNA damage
why is metaphase anaphase transition blocked by chromosomes
chromosomes still attached to spindles fibres
what type of cells are in meiosis
haploid cells
what type of cells are haploid
gametes
what is formed when a egg and sperm meet
zygote
when does crossing over happen in meiosis
during meiosis 1
what’s the point of crossing over
new allele combinations
what is non disjunction
sister chromatids don’t separate properly
which cell cycle do budding yeast go through
bacteria cell cycle not human
which CDK binds to cyclin C
3
which CDK binds to cyclin E and D
2,4,6
which CDK binds to cyclin A
1,2
which CDK binds to cyclin B
1
what does cyclin A do
activates S phase and G2
what does cyclin D and E do
G1 to S
what does cyclin B do
G2 to M
when does cyclin C activate
G0
what regulates phase transitions
cyclins + CDKs
what is the restriction point
G1 to S transition
what supresses CDKs
CDKIs
