Topic H Flashcards
Interphase
- organelles double in number/volume
- DNA and centrosome rep.
- cell elongates (plant cells)
Prophase
- Centrosomes move to poles
- chromosomes condense
Prometaphase
- Nuclear envelope dismantels
- MT connect to targets
Metaphase
- chromosomes move to middle
Anaphase
- Chromatids separate
- chromosomes move to poles
- cell elongates (animal cells)
Telophase
- chromosomes de condence
- nuclear envelope reforms
Cytokinesis (animals)
- contractile ring
Cytokinesis (plant cells)
- vesicles containing cellulose fuce to make cell wall
Chromosome proteins
- Histones
- Cohesins
- Condensins
- Kinetochore
Histones
- balls of 8 little proteins
- compact DNA
- When: Always
- where: Everywhere
Cohesins
- Large heteotrimer rings
- 3 polypeptides
- proteins that load onto DNA in G1
- old sister chromatids together –> need to be put on before DNA replication (Replication Fork pass through the ring during DNA replication)
- When: G1 –> anaphase
- where: centromeres
Condensins
- hold and connect DNA
- Similar to Cohesins
- when: Prophase –> telophase
- where: Everywhere
Condensins proteins are added during _____
Prophase
Kinetochore proteins
- connect MT to centromere region of DNA
- When: metaphase –> prophase
- where: Centromere
Cellulose
- polysaccaride
- cell wall
- beta glucose monomer
Plant cells in a ___ Environment
Hypotonic
Cells ____ before mitosis
elongate
Intermediate filaments during:
interphase
interphase: nuclear lamina
Intermediate filaments during: Prometaphase
Prometaphase: nuclear lamina are temporarily deactivated (break into parts)
Intermediate filaments during: Telophase
nuclear lamina are re-activated (reassembles around chrom. resealing nuclear environment)
Microtubules: prometaphase (3)
Aster MTs
Kinetochore MTs
Interpolar MTs
Aster MTs
inner surface of plasma membrane
Anchors Centersomes
makes sure its stationary
Kinetochore MTs
kinetochore proteins at centromere DNA
Move Chrom. to middle of cell during metaphase
Interpolar MTs
Mts from opposite poles
Elongate cells
Cytokinesis (plant and animal cells)
MT during metaphase
MT search for and capture Chromo.
Only attach when it can withstand pulling forces are stabilized
MT during Anaphase
kinetochore MT disassemble
T/F
Aster MT stop centrosomes from being pulled into middle of cell
T
____ MT form extension bundles and elongate cell
Interpolar MT
Kinetochore MTs are ___ end directed & ___ motor proteins
Plus; kinesin
Anaphase A
Chromosomes pulled towards centrosomes
Anaphase B
Centrosomes move apart
MT during cytokinesis in plant cells, ____ move into middle of the cell on ___ MTs
Vesicles contain cellulose; Interpolar
What happens with Actin Filaments during cytokinesis in animal cells
ring forms close to Interpolar MTs
The Cell cycle is regulated by what 4 protein complexes
G1-Cdk
S-Cdk
M-CdK
APC
G1-Cdk
G1-Cdk = G1-Cyclin + Cdk Mechanism: phosphorylation # of targets: 2 prep for DNA rep. G1 checkpoint --> near end of G1
S-Cdk
S-Cdk = S-Cyclin + Cdk Mechanism: phosphorylation # of targets: 2 Start DNA rep (sphase) G1 --> S phase
M-CdK
M-CdK = M-Cyclin + Cdk Mechanism: phosphorylation # of targets: 6 Starts prophase (mitosis) G2 checkpoint -- G2 --> prophase
APC
Anaphase promoting complex
starts anaphase
Mechanism: attach ubiquitin proteins to target protein
# of targets: 2
M checkpoint – Metaphase —> anaphases
Cyclin Cdks are regulated by…(3)
availability of cyclins
phosphorylation
inhibitor proteins
What do kinases do?
Phosphorylate target proteins (turn on)
Cdk
Cyclin dependent kinases (Cdks)
act during cell cycle
Cyclins
activate Cdks and dictate their target
Cdk are activated by ____
Cyclins
Cdk are activated AND inhibited by ____
phosphorylation
Cdk are activated AND inhibited by ____
phosphorylation
Polyubiquinated protiens are broken down by ____
Proteasomes
Polyubiquinated proteins are broken down by ____
Proteasomes
When does G1-Cdk become activated and inactivated?
Addition of Phosphate/ removal of phosphate
When does S-Cdk become activated and inactivated?
Addition of Phosphate/ removal of phosphate
When does M-Cdk become activated and inactivated?
Addition of Phosphate/ removal of phosphate
When does APC become activated and inactivated?
Addition of Ubiquitin protein / removal of Ubiquitin protein
___ indirectly activates Transcription factors
G1-Cdk
cell receives a signal then ___
G1 cyclin synthesized turning on G1-Cdk
G1-Cdk activating Transcription factors mechanism?
: G1-Cdk inactivates the inhibitory Rb proteins
Oris
Origin of replication
Where DNA rep starts (rep. fork)
____ indirectly actiavtes S-Cdk
G1-Cdk
ORC (origin recognition complex) and helicases put onto oris during ___
G1
Oris fire once at the start of ____
s Phase
S-Cdk triggers ___
s Phase
Oris can’t fire a second time (T/F), explain.
T –> once/ cell cycle
ORCs phosphorylated Therefore inactive till next cell cycle
not enough helicases available
___ indirectly activates the centrosomes for centrosome duplication/rep
S-Cdk
Mitosis is use to rep. the nucleus (T/F)
T
1 per cell –> 2 per cell
___ is activated when DNA rep. and repair are complete
M-Cdk
___ prevents activation of M-Cdk
ssDNA
if M-Cdk is actived then ____
the cell is ready to finish interphase and do mitosis
An ___ phosphate is removed by a ___ to activate Mcdk
inhibiting; phosphatase
____ activates MT regulatory proteins
M-CdK
____ inactivates Nuclear lamins and dismantles ____; during ___
M-Cdk; nuclear envelope; prometaphase
____ inactivates Nuclear pore proteins
M-Cdk
____ activates condensin proteins
M-Cdk
What stops during mitosis and why
DNA repair and RNA synthesis; must all stop since chrom condensed
Myosin are temporarily inactivated by what?
inhibitory phosphate
___ activated by M-CdK
APC
____ inactivated by unattached chromosomes
APC
___ indirectly destroys Cohesins
APC
Steps for APC indirectly destroys Cohesins
- APC destroys securin (which then activates separase)
2. separase destroys cohesins by proteolysis
___ destroys M-Cdk
APC
what changes caused by M-Cdk are reversed?
MT return to interphase behavious
Nuclear pores and Lamina reform
Chromosomes decondense (Membrane and chrom fuse to become 1 nucleus)
APC inactivates
Each chrom. gets a coating of _____ and _______ ad it expands
Nuclear lamins; ER membrane
Why is the membrane coat tight
to exclude cytosolic proteins
Cytokinesis in animials cells is done by what
actin filaments + Myosin
Cytokinesis in animials cells steps
- inhibitoy phosphates are removed
- contraction bundels contract
- squeezing the middle making 2 cells
In G1 all regulatory proteins are _____
inactive
G1-Cdk is activated by ____ in unicellular Euk and ___ in multicellular Euk.
large cell volume; mitogens
G1-Cdk, S-Cdk, and M-Cdk are inhibited by ___ so that the cell cycle pauses while the ___
DNA damage; DNA is repaired
M-Cdk is inhibited by ____ to prevent prophase starting before S phase is complete
incompletely replicated chromosomes
APC is inhibited by ____ to prevent anaphase from starting before metaphase is complete
unattached chromosomes
steps of repairing blood vessel damage
blood vessel damage –> Platelet cell –>PDGF –> Fibroblast reproduction –> collagen
to make collagen what signal is needed
paracrine
What happeneds if the DNA is damaged
all euk cells stop cell cycle
inhibition of G1Cdk SCdk and MCdk
p53
53 kDa protein
+ transcription factor
regulated at the level of
p53
53 kDa protein
+ transcription factor
regulated at the level of protein stability
___ indirectly stops cell cycle. process?
p53
moderate dna damge –> p53 turns on p21 gene (Cdk inhibitor protien)
___ indirectly fixed DNA damage. process?
p53
moderate dna damge –> p53 turns on DNA repair Enzyme genes
p53
53 kDa protein
(+) transcription factor
regulated at the level of protein stability
