Mitosis

Question 1

Preceding stage of mitosis?

Answer 1

Interphase

• DNA and organelle replication occurs
• increase in ATP content
• 3 stages of interphase are G1, S and G2
• G1: Cell Growth
• S: DNA replication
• G2: Preparation for mitosis

Question 2

First stage of mitosis?

Answer 2

Prophase

• Chromosomes condense and supercoil which makes them easier to move and protects them
• they appear shorter and fatter
• In later stages of prophase pairs of sister chromatids can be seen attaching to the centromere
• Nuclear envelope breaks down
• Spindle fibres appear

Question 3

Second stage of mitosis?

Answer 3

Metaphase
-homologous chromosomes line up at the center of the cell on the equator and attach to spindle fibres at the centromere
One sister chromatids from each chromosome is attached by spindle fibres to one pole, the other is attached to the opposite pole.

Question 4

Third stage of mitosis?

Answer 4

Anaphase

• spindle fibres contract, microtubules shorten and poles move further apart
• causes sister chromatids to be drawn apart to opposite poles of the cell
• once separated they are referred to as ‘daughter chromosomes’

Question 5

Fourth stage of mitosis?

Answer 5

Telophase

• begins once two sets of daughter chromosomes reach the two poles of the cell
• nuclear membrane reforms
• two nuclei present again
• chromosomes uncoil so become less visible
• spindle fibres disappear

Question 6

Final stage of mitosis?

Answer 6

Cytokinesis

• occurs after telophase or during
• formation of a cleavage furrow
• cytoplasm divides