46. PROMETAPHASE, METAPHASE, ANAPHASE, TELOPHASE & CYTOKINESIS Flashcards
1
Q
- When does Prometaphase begin?
A
- it begins upon the completion of the Nuclear Envelope Degradation
2
Q
- What are the 2 stages of Prometaphase?
A
- Chromosomes attach to the Spindle Microtubules
- Chromosomes move towards the Cell Centre
(Metaphase Plate)
3
Q
- What happens when the Chromosomes attach to the Spindle Microtubules?
A
- each chromosome is then connected to both poles
- one chromatid has an orientation towards one pole
- the other chromatid has an orientation towards the
other pole
4
Q
- What causes the Chromosomes to move towards the Cell Centre?
A
- the polymerisation and the depolymerisation of the Kinetochore Microtubules
5
Q
- What happens during Metaphase?
A
- the chromosomes align in the Equatorial Plane
(Metaphase Plane)
6
Q
- What happens if the chromosomes are not aligned correctly?
A
- the cell cycle will stop the signal
- this is in order for repairs to occur
7
Q
- What happens during Anaphase?
A
- SISTER CHROMATID SEPARATION:
- this is due to the inactivation of centromere proteins
- these proteins hold the two chromatids together - SISTER CHROMATIDS MOVE:
- they move along the Kinetochore Microtubules
- they move towards the opposite ends of the cell
8
Q
- What are the two stages of Anaphase?
A
- ANAPHASE A:
- this is the depolymerisation of Microtubules
- this is Tubulin Polymerisation
- ANAPHASE B:
- this is the separation of the 2 poles
- this is Spindle Elongation
9
Q
- What happens during Anaphase A?
A
- the chromosomes start moving toward the poles of the
spindle - the motor proteins are involved in this process
- they are found at the Kinetochore
10
Q
- What happens during Anaphase B?
A
- the Non-Kinetochore Microtubules overlap and push
against each other - these microtubules come from opposite poles
- this elongates the cell
- motor proteins are involved in this process
11
Q
- During Telophase, what is found on the opposite poles of the cell?
A
- identical daughter nuclei
12
Q
- What are the 3 stages of Telophase?
A
- Chromosomes are transferred at the opposite
poles of the cell
(This happens at the end of anaphase and at the
beginning of telophase) - Reformation of the Nuclear Envelope
- this is upon the vesicle fusion around the
chromosomes
- this is upon the vesicle fusion around the
- Reformation of the ER and the Golgi apparatus
13
Q
- What happens during Cytokinesis?
A
- the cytoplasm divides into 2 daughter cells
- a contractile ring forms
14
Q
- What is a Contractile Ring?
A
- a ring of actin and myosin microfilaments
- This ring contracts
- it contracts until it brings the opposite ends the cell
in the the middle - the opposite ends then connect to each other
- this completely splits the cell into 2
15
Q
- What does Cytokinesis in plants involve?
A
- it involves a cell plate formation