Cell Division

Question 1

What are the 3 stages of the cell cycle

Answer 1

-interphase
-mitosis
-cytokinesis

Question 2

Summarise interphase

Answer 2

● DNA replicates semi-conservatively (S phase)
- Leading to 2 chromatids (identical copies) joined at a centromere
● Number of organelles & volume of cytoplasm increases, protein synthesis (G1 / G2)

Question 3

Summarise mitosis

Answer 3

● Nucleus divides
● To produce 2 nuclei with identical copies of DNA produced by parent cell

Question 4

Summarise cytokinesis

Answer 4

● Cytoplasm and cell membrane (normally) divide
● To form 2 new genetically identical daughter cells

Question 5

Mitosis + cytokinesis=

Answer 5

M phase ( typically 1 hour in mammalian cells)

Question 6

…….. cells in the foetus are able to develop into any type of cell

Answer 6

Totipotent

Question 7

Consequences of differentiation for many cells is that they lose the ability to……

Answer 7

Divide

Question 8

Stem cells constantly remain in the ……. …….. ……….. , they contribute daughter cells, which may either become stem cells like the parent, or differentiate according to the cell line (e.g. ……… blood cells)

Answer 8

1. cell growth cycle
   2.white

Question 9

What are chromatids

Answer 9

• Chromatid: one copy of a duplicated chromosome
• formed by DNA replication
• still joined to the other copy.
• Sister chromatids separate at mitosis.

Question 10

Describe the behaviour of chromosomes and role of spindle fibres in mitosis

Answer 10

Question 11

Draw each stage of the cell cycle

Answer 11