Cell cycle Flashcards
What are the phases of the cell cycle
G1, S, G2 and M
Describe the characteristics of G1 phase
cell size maintained, nutritional control, variable length
What happens in S phase
DNA replication
Describe the characteristics of g2 phase
Growth, DNA has been replicated, centrosomes have been duplicated
How can you detect what phase of the cell cycle a cell is in
fluorescent DNA dyes determine DNA content in cells
How long is M phase
less than 1 hour in humans
What stage of M phase can cells pause
metaphase
What is the mitotic spindle comprised of
centrosomes, spindle microtubules and asters
What is the function of the mitotic spindle?
segregates chromosomes into daughter cells
What is the aster
radial array of short microtubules
what is the kinetochore?
large protein complexes
where does the kinetochore assemble
chromosomes and centromeres
What is the function of the kinetochore?
mediate attachment of mitotic spindle to microtubules
What are the different types of microtubules
astral microtubules, kinetochore microtubules, inter-polar microtubules
Which microtubules are structural
inter polar and astral
what is the function of kinetochore microtubules
pulls apart chromosomes
What happens in prometaphase
nuclear envelop breaks down, attachment of chromosomes to spindle
What happens in metaphase
chromosomes align on the equator, chromatids pulled towards pole
what happens in telophase
new nuclear envelope forms, chromosomes de-condense
What happens in cytokinesis
cytoplasm is divided in two by a contractile ring of actin and myosin filaments
What are the checkpoints of the cell cycle?
G1 - S, G2-M and Metaphase - anaphase
Which checkpoint operates through negative signalling ONLY
metaphase to anaphase
What regulates the cell cycle
Cyclin activated kinases
What do CDKs requires for functionality
cyclins
