Unit 1.5 - (mitosis)

Question 1

Prophase (1)

Answer 1

-Chromosomes condense to become visible, to stop transcription and to prevent tangling during separation.
-The cytoskeleton breaks
down and its parts are used to begin spindle formation between centrosomes.
- The nuclear membrane starts to break down.

Question 2

Metaphase (2)

Answer 2

-The chromosomes are lined up along the cell’s equator.
These are
held in place by microtubules from each pole attached to each
centromere. The phrase ‘Metaphase Plate’ refers to the
arrangement of chromosomes at the equator during metaphase.

Question 3

Anaphase (3)

Answer 3

The centromeres divide and the sister chromatids have become
chromosomes. The chromosomes are pulled along the microtubules
toward opposite poles of the cell.

Question 4

Telophase (4)

Answer 4

The chromosome have migrated to the poles. The nuclear
membrane reforms. The mitotic structures breakdown. The
chromosomes uncoil.

Question 5

Cytokinesis (5)

Answer 5

Cytokinesis occurs at the end of telophase and involves the
separation of the cell into 2 daughter cells.

Question 6

Interphase (0)

Answer 6

G1, S , G2

Question 7

Proto-onco genes

Answer 7

A proto-oncogene is a normal gene, usually involved in the control
of cell growth or division, which can mutate to form a tumour-
promoting oncogene. These oncogenes cause the cell to divide in
an uncontrolled and unregulated manner.

Question 8

Apoptosis reasons

Answer 8

main: DNA damage occured
others: To kill cells that have been infected by pathogens.