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Genetics
Block 4 Set 1
35
Other
Graduate
03/23/2009

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Term
mitosis
Definition
Distribution of chromosomes (nuclear division) and cytokinesis
Term
interphase
Definition
during this stage Cell growth and DNA replication
Term
Labile cells e.g. cells of epidermis
Definition
no all cells undergo the process of mitosis because they are in continuous cyclization. Give an example.
Term
Stable cells e.g. skin fibroblasts, hepatocytes
Definition
these types of cells exit G1 to enter a quiescent stage called G0, where they are metabolically active but no longer proliferate;
If there is stimulus (e.g. injury)  reenter G1
Give an example
Term
S
Definition
to identify DNA in what stage of the cell cycle is the incorporation of radioactive thymidine made
Term
late G1
Definition
Most animal cells proliferation is regulated in ? which is also known as the Restriction point (similar to START in yeasts)
Term
PDGF
Definition
Injury to skin fibroblasts causes platelets to release? and then the cells can re-enter the G1 phase
Term
oocyte
Definition
A few cell are controlled in G2 phase (G2 to M)
Remain arrested in G2 for a long time
Hormonal stimulation
Progression to M phase
Give an example
Term
G2 checpoint
Definition
Senses unreplicated DNA and prevents mitosis before completion of S phase
Also checks for DNA damage
Term
S checkpoint
Definition
Checks for DNA damage and errors of replication
Term
M
Definition
this check point occurs towards the end (Spindle assembly checkpoint )
Monitors alignment of chromosomes on spindle
Chromosomes not allowed to separate until a complete compliment of chromosomes is organized for distribution to daughter cells
Term
minichromosome maintenance (MCM) helicase proteins
Definition
They bind to replication origins along with origin recognition complex (ORC) proteins
Can bind to replication origins only during G1 phase
Once bound allow replication to initiate
Displaced from origin as replication progresses
Term
protein kinases
Definition
block the association of MCM with origins during S, G2 and M phases
Term
cyclin dependent kinases (CDK)
Definition
are protein kinases that play a prominent role in regulating cell cycle progression
Term
cyclins
Definition
are regulatory subunits required for the catalytic activity of Cdk’s
Term
(Cdk4 & Cdk6; D)
Definition
Name the CDK and the Cyclin associated with the restrction point
Term
(Cdk2; E)
Definition
Name the CDK and the Cyclin associated with G1 to S
Term
(Cdk1; B)
Definition
Name the CDK and the Cyclin associated with G2 to M
Term
(Cdk2; A)
Definition
Name the CDK and the Cyclin associated with progression through the S phase
Term
(Cdk1; A)
Definition
Name the CDK and the Cyclin associated with S to G2
Term
Maturation promotion factor (MPF)
Definition
Cdk1 + cyclin A or B --> also called
Term
threonine
Definition
Cdk-cyclin complex activation requires phosphorylation of ____ at 160
Term
Wee1 protein kinase and cdc25 family of protein phosphatases
Definition
what inhibits the cdk cyclin complex by Inhibition by phosphorylation at Cdk amino terminal region
Term
INK4
Definition
bind to monomeric Cdk4 and Cdk6 --> inhibit progression through G1
Term
Cip/Kip family
Definition
bind to Cdk1 and Cdk2--> inhibit progression through all phases of cell cycle E.g. p21
Term
growth factor stimulation
Definition
activates Ras/Raf/MEK/ERK signaling pathways--> stimulate synthesis of cyclin D1
Term
D1 complexes with Cdk4 & 6
Definition
are responsible for phosphorylation of Rb protein
Term
Rb Protein
Definition
Normally underphosphorylated, binds to E2F family of Transcription factors and keeps them inactive
Phosphorylation--> releases E2F--> activation of transcription of target genes--> one of which is cyclin E--> complexes with Cdk2
Term
Cdk2/cyclinE
Definition
Phosphorylates Rb  complete inactivation
Activate MCM helicase protein  replication initiation and entry into S phase
Term
oncogenes
Definition
Proteins that drive cell proliferation
Growth factors Ras, Raf, MEK,ERK & cyclin D
Mutation leads to increased cell proliferation
Term
tumor suppressor genes
Definition
Act as brake to cell cycle
Loss of function leads to increased cell proliferation
Rb protein
Term
ATM and ATR
Definition
protein kinases which are part of protein complexes that recognize damaged or unreplicated DNA--> activate checkpoint kinases (CHK2 and CHK1 respectively)--> cell cycle arrest
Term
p53
Definition
In addition G1 arrest is also mediated by __; it is also Transcription factor --> induces p21--> inhibits Cdk1/cyclinE complex
Term
Ataxia telangiectasia
Definition
a mutation in ATM leads to?
Term
mutations in p53
Definition
most common genetic alteration in cancers
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