11 Cell cycle and division II
2nd Term WS 13
(b) Y → X → Z → W
(c) The cells have no cell wall.
(d) The chromosomes are not in homologous pairs. /
Only two cells are produced in stage W. /
No chiasmata are formed between chromosomes. (any 2) 1m x 2
(a) R ® S ® Q ® T ® P
(b) The DNA content of the cell at stage R is double that in a cell at stage P.
After stage R, the chromosomes in the cell separate into two equal groups
and each group goes to a daughter cell.
As chromosomes are made up of DNA, mitotic cell division reduces
the DNA content of the cell at stage R by half.
(c) To produce new cells for growth. 1m
To produce new cells for replacing worn-out or damaged cells.
For asexual reproduction in some organisms to produce offspring. 1m
(a) (i) Chromosomes were / chromatin / nucleus was visible after staining. /
Staining enabled the determination of different stages in mitosis / cell cycle. /
Staining provided contrast between cell structures. (any 2)
1m x 2
(b) 4.34% + 3.23% + 3.23% + 7.20%
100% – 82%
(c) In meiosis, the cells produced are not genetically identical. /
In meiosis, the cells produced have only one set of chromosomes / are haploid. /
In meiosis, the cells produced are gametes. /
In meiosis, four cells are produced. 1m