L2 Flashcards
cleavage
rapid division of cells
of cells in cleavage increase ____ and in a ___ fashion
rapidly
logarithmic
properties of cleavage (5)
splits the single cell of the fertilized egg into 100s of cells
usually synchronous
leads to cells of reduced size as growth does not occur
modified cell cycle allows quick cell divisions
dependent upon proteins and mRNAs stored in fertilized egg
in a modified cell cycle (in drosophila), how is it modified?
only mitosis + s phase - no transcription, no RNA polymerase - only DNA polymerase
what species has the following cleavage patterns?
radial
discoidal
bilateral
superficial
spiral
rotational
amphibians
fish + birds
sea squirts + tunicate
drosophila
snail
mammals + C. elegans
cleavage pattern is determined by what
yolk thickness
what is the direction of snails a classic example of?
maternal effect
compaction
different cells become hard to distinguish bc of strong cell adhesion
_____ is a protein that is really important for division
string
CDK1 is present throughout the cell cycle, but is only active during what transition
G2 –> M
_____ accumulates in late G2
controlled by the phosphorylation of other proteins
cyclin B
____ removes the inhibitory phosphate on Tyr-15 activating ___ during mitosis
Cdc25
CDK1
string is the drosophila homolog of ___
Cdc25
CDK1 phosphorylates what three thins
histone 1
MAP
Lamin
histone 1 does what
chromosome condensation
MAP does what
spindle formation
causes microtubules to become dynamic
lamin does what
nuclear envelope breakdown
zygotic expression is initiated at the _____ transition by the changing ratio of ___ to ____
midblastula
nuclei
cytoplasm
in cell division after cleavage, what are some properties ? (4)
not synchronous
occurs in specific regions which are associated with organ formation
G1 and G2 phases are introduced into the cell cycle
dependent upon zygotic transcription
what are the different cleavage patterns?
radial
discoidal
bilateral
superficial
(spiral)
(rotational)
_____ phosphorylates CDK1 on ______ to prevent activation during G2
Wee1
Try-15
_____ removes the inhibitory phosphate on Try-15 activating CDK1 during mitosis
Cdc25
string is drosophila’s homologue of what?
cdc25
without cdc25, you would never enter ____ again
mitosis
spindle causes _______ to become dynamic
microtubules
zygotic expression is initiated at the _______ by changing the ratio of ____ to _____
midblastula transition
nuclei
cytoplasm
