Mitosis

Question 1

What are the 4 stages of mitosis?

Answer 1

Prophase
Metaphase
Anaphase
Telephase

Question 2

What happens in prophase?

Answer 2

• Nuclear envelope breaks down and nucleolus disappears
• Sister chromatids condense into chromosomes and become visible
• Centrioles separate and move to opposite poles of the cell

Question 3

What happens in metaphase?

Answer 3

• Chromosomes line up along the equator of the cell
• Spindle fibres are released to attach to the centromere and chromatid

Question 4

What happens in anaphase?

Answer 4

• Spindle fibres retract and pull centromere and chromatids toward opposite poles
• Centromere divides into 2 and individual chromatids are pulled to each opposite pole
• This stage requires ATP provided by respiration in mitochondria

Question 5

What happens in telephase?

Answer 5

• Nuclear envelope and nucleolus reform
• Chromosomes unwind into sister chromatids
• Spindle fibres disintegrate

Question 6

How do you recognise the stages of mitosis under a microscope?

Answer 6

Position of chromatids / chromosomes
- No arrangement / no spindle: prophase
- Equator: metaphase
- Moving towards poles: anaphase
- Poles: telephase

Question 7

How do you calculate mitotic index?

Answer 7

(No of cells with condensed chromosomes ÷ total no of cells) x 100