Le Cycle Cellulaire 1:

Question 1

What are Cdks?

Answer 1

kinase dependent de cyclines
Different Cdk-C control the cell cycle and assure a unidirectional flow

Question 2

What is the method of Cdk activity control?

Answer 2

degradation via proteosomes and ubiquitine

Question 3

What are the 2 Protéasomes?

Answer 3

Proteasomes:

Spécifiquement des protéines solubles présentes dans le cytosol et le nucléoplasme (facteurs de transcription, etc)

Lysosomes:

spécifiquement les protéines enfermées dans des
vésicules

Question 4

What kind of signal would you excpect as you enter the M phase?

Answer 4

High activity of Cdk-M

Question 5

At what stage do we find the SAC checkpoint?

Answer 5

transition métaphase/anaphase

Question 6

What is the state of the cells in Prophase?

Answer 6

2 centrosomes se séparent en
prophase pour former le fuseau
mitotique

Question 7

What are condensines?

Answer 7

condensines facilitent l’enroulement des
chromatides (la condensation) pendant la
prophase

Question 8

What are the 4 cycle of M phase?

Answer 8

Prophase
Pro metaphase
Metaphase
Anaphase
Cytocinese

Question 9

What is the key action in prometaphase?

Answer 9

enveloppe nucléaire se démembre en
prométaphase

cellule s’arrondi en pro-métaphase en
préparation pour la division

Les kinétochores se forment au
centromères

Question 10

What process will determine if we will be stuck in prometaphase?

Answer 10

• Kinetochores:Formed at centromeres using specialized histone: CENP-AThere will be 46 pairs of kinetochoresIf we have not well aligned kinetochores the cell will remain in prometaphase

Question 11

What inhibits APC activity?

Answer 11

Kinétochores
mal-alignés
inhibent l’APC

Question 12

What are the roles of APC (2)?

Answer 12

Anaphase
promoting
complex
(APC)

1. It is what ubiquitinates the Cdk-M protein which will allow to go from Metaphase to Anaphase
2. It is involved in detatching the securin from separase -> cleavage of cohesines -> separation of chromatids

Question 13

In a SAC on cell the APC activity is what?

Answer 13

Inhibited by the misalignment of kinetochores

Question 14

What are cohesins, how are they degraded?

Answer 14

When the chromatids are replicated they stay stuck together:

This is done via cohésines

Cohésines are broken down before entering anaphase:

This process is also APC dependent:

This is done via the breakdown of securin which leads to increased activity of separase which will cleave the cohesines

Question 15

Main activity in Anaphase:?

Answer 15

separation of chromatids

Question 16

Main activity in Telophase:?

Answer 16

Chromosomes that are separated will begin to de-condense

The nucleus membrane will begin to reform

Question 17

Main activity in Cytocinèse?

Answer 17

division du cytoplasm

Actin and Myosin dependent