Test2day2 Flashcards
What separates in anaphase of mitosis?
What separates in anaphase of meiosis one?
What separates in anaphase of meiosis two?
sister chromatids
homologous chromosomes
sister chromatids
The place where maternal and paternal chromosomes have exchanged DNA is called a ___
Chiasma
N+1 N+1 N-1 N-1 occurs from nondisjunction at what stage?
N+1 N-1 N N occurs from nondisjunction at what stage?
Metaphase in meiosis 1
Metaphase in meiosis 2
The insulin like growth factor is only expressed from the gene inherited from the father. What type of imprinting is this?
Maternal because the mom’s gene is silenced
What is uniparental disomy?
Heterodisomy occurs how?
Isodisomy occurs how?
When someone receives two copies of a chromosome from one parent, and none from the other.
Nondisjunction at meiosis 1 (Pair of non-identical chromosomes is inherited from one parent)
Nondisjunction at meiosis 2 (Single chromosome from one parent is inherited)
Which chromosome does Prader Willi syndrome have an effect from? Also, explain why this disease occurs and how it relates to genomic imprinting
15
The maternal copy of this gene is imprinted (so mother’s genes are silenced). The disease occurs when the fathers genes, that are suppose to be the only ones expressed, are either deleted or also silenced. Then, there is no expression at all of these genes on chromosome 15. Isodisomy is one way this can occur (If the genes inherited are only the mothers, but since it’s silenced, no gene expression at all).
___ is the idea that females have x-inactivation of one of their x-chromosomes so that they don’t have twice as many x gene products as males
Lyonization
Name the phases of interphase and what they do
G1 - RNA and protein synthesis needed for DNA replication
S phase - DNA is replicated (synthesized)
G2 - DNA stability is checked and cell prepares to divide
When a cell passes the ___ it becomes growth factor independent. Also, where is this located?
Restriction point, G1 phase
(If not enough growth factors present, the cell does not pass through the restriction point. Once it does however, it is no longer dependent on growth factors)
Name the checkpoints
1) Makes sure the chromosomes were duplicated correctly before committing to mitosis.
2) Ensures chromosomes are attached to the mitotic spindle
3) Corrects any DNA damage (such as that from chemical modifications like methylation) before continuing
1) G2 checkpoint
2) M checkpoint
3) G1 checkpoint
Initiation of S phase protein synthesis requires the transcription factor ___
E2F
Take the question step by step.
In order to get past the G1 checkpoint, Myc must activate cyclin __ and CDK __ or __.The enzyme responsible for the complete activation of the cyclin-CDK complex is ____; now, this active complex must phosphorylate __, inactivating it and releasing the transcription factor ___, which then goes on to activate cyclin __ and CDK __ which allows the transition from G1 to S to be accomplished. Cyclin __ and CDK __ is responsible for the continuation of the S phase and both of these 2 Cyclin-CDK complexes that were activated by E2F keep the RB phosphorylated so it cant become active again. In order to activate mitosis, cyclin __ or ___ and CDK ___ is active
d, 4 or 6, CAK (CDK-activating kinase), Rb (retinoblastoma protein), E2F, E, 2, A, 2, A, B, 1
Normally, cyclin-CDK is activated by phosphorylation from CAK, however, if the complex is phosphorylated again at the roof site of CDK, it is deactivated. What is this enzyme called that phosphorylates it for a second time? The cyclin-CDK complex can have its second phosphate group removed to reactive it (now it’ll only have one phosphate group aka the active one). What enzyme can remove the second added phosphate?
Wee1 Kinase
Cdc25 phosphotase
What is the role of p27?
It binds to the cyclin-CDK complex to inhibit its kinase activity (belongs to a group of CDK inhibitors called CKIs)
Proteolysis (protein degradation) can be a way of degrading cyclin proteins. The progression of metaphase to anaphase is triggered by protein destruction due to the ___ complex
APC/C (Anaphase promoting complex or cyclosome)
What does the activation of P53 do?
P53 activates CKI,s (like P27, P21 etc.) which bind to cyclin-CDK complexes to stop the cell cycle at G1 so it can enter G0 and be repaired. (In short, DNA damage leads to p53-mediated cell cycle arrest at the G1 checkpoint)
