2.4 Cell Division

Question 1

What are the stages of the cell cycle in eukaryotic cells?

Answer 1

• Interphase
• Mitosis (PMAT)
• Cytokinesis

Question 2

Interphase

Answer 2

• DNA replicates (S phase)
• Organelles replicate and cell grows (G1 and G2)

Question 3

Prophase

Answer 3

• Chromosomes condense and become visible, appearing as 2 sister chromatids joined by a centromere
• Nuclear envelope breaks down
• Centrioles move to poles forming spindle

Question 4

Metaphase

Answer 4

• Spindle fibres attach to chromosomes by their centromeres
• Chromosomes align along equator

Question 5

Anaphase

Answer 5

• Spindle fibres contract
• Centromere divides
• Pulling chromatids to opposite poles

Question 6

Telophase

Answer 6

• Chromosomes uncoil, becoming thinner
• Nuclear envelope reforms
• Spindle fibres break down

Question 7

Cytokinesis

Answer 7

• Cytoplasm and cell membrane divides
• Forming 2 genetically identical diploid daughter cells

Question 8

Why is mitosis important?

Answer 8

• Growth of multicellular organisms
• Replacing cells to repair damaged tissues
• Asexual reproduction

Question 9

How can cancers form?

Answer 9

• Mutation in genes controlling mitosis
• Leading to uncontrollable cell division
• Resulting in a tumour / mass of abnormal cells

Question 10

How do prokaryotic cells replicate?

Answer 10

• Binary fission
• Circular DNA replicates
• Plasmid(s) replicate
• Cytoplasm divides to produce 2 daughter cells
• One copy of circular DNA but variable number of plasmids