2. (a) Read through the following passage about mitosis and then complete
it by writing the most appropriate word or words in the spaces.
In flowering plants the process of mitosis is restricted to the apical
and to
In growing mammals
mitosis can occur throughout the body.
However, not all regions of the young mammal grow at the same
rate and this is called
growth.
In the cell cycle, replication of DNA occurs in the..
.............phase,
after which there is a lag or gap phase, called the
phase,
before actual mitosis starts. The chromosomes also replicate before the
onset of mitosis, but this replication is not visible until the middle of the
. stage.
At this stage, each chromosome consists of two
..held
together by a

1) G1 (gap 1) phase: This is the first phase of the cell cycle that has to do with an increase in the size of the cell. Major cellular components duplicate in size here.

2) S-phase: DNA replication occurs here.

3) G2 (gap 2) phase: This is the gap phase that comes after the S-phase. The cell undergoes further growth here and the organelles of the cells are also prepared for cell division.

4) Mitotic phase: There are four stages here

i) prophase: Chromosome condenses and becomes visible at this stage. And there is the emergence of spindle fibre from centrosomes.

ii) metaphase: Spindle fibre develops and sister chromatids are attached to

separate spindle.

iii) anaphase: Cohesin, which holds two sister chromatids (of chromosomes) together, breaks down and are pulled towards opposite poles.

iv) telophase: Chromosomes begins to decondense at opposite poles and actual cell division starts as mitotic spindle breaks down.

NOTE: All possible answers to the question are underlined