Mitosis

Question 1

Phases of the cell cycle?

Answer 1

Interphase - G1 Synthesis (DNA replication) G2

M-phase - Mitosis and cytokinesis

Question 2

Phases of mitosis?

Answer 2

IPP MAT CI

Prophase - Prometaphase - Metaphase - Anaphase - Telophase

Followed by cytokinesis

Question 3

Mitotic spindle?

Answer 3

Centrosomes - microtubulus - asters

Microtubuls connect to kinetochore on each sister chromatid

Tug of war between the poles - moves it to the middle of the cell

Question 4

Cytokinesis?

Answer 4

Cleavage furrow - with a ring of actin and myosin filaments

Question 5

Cell cycle control system?

Answer 5

Protein kinases and cyclins - cyclindependant kinases - Cdks - activity is dependant on the concentration of cyclin

High in S and G2 and Low in M phase

MPF - triggers the passage to the m-phase and cyclin and Cdk keeps the MPF complex active.

Provides go ahead signals to at some checkpoints

Question 6

M-checkpoint?

Answer 6

At anaphase - does not begin until all chromosomes are attached to the spindle and the proteincomplex becomes active which activates separase that cleaves cohesins.

Question 7

S-checkpoint?

Answer 7

Stops cells with DNA damage from proceeding in the cycle.

Question 8

External signals?

Answer 8

Density depedant inhibition - Crowded cells stops dividing

Anchorage dependance - Must be attached as a inside of a flask or ECM of a tissue