5.4.1 Mitosis (Structured Question 1 & 2)


Question 1:
Figure I shows cells R and S undergoing cell division.


(a)(i)
Name the structures labelled K and M.

(a)(ii)
State the phase of division of cells R and S.


(b)
Cell R undergoes three consecutive divisions.

(c)(i)
Cell S undergoes the first nuclear division and produces two cells.
Complete the diagram to show the chromosomes in one of the cells produced.

(c)(ii)
Name one organ where cell S is found.

(c)(iii)
The number of chromosomes I a somatic cell of a fly is 12.
State the number of chromosomes in a daughter cell produced at the end of the type of cell division as shown by cell S.


(d)
Cancer is a disease which causes uncontrolled growth of tissues.
Radiotherapy is a method to treat cancer by using radiation.
Explain how this treatment stops the growth of cancer cells.

(e)
An oil palm planter wants to produce a large number of oil palms in a short time.
State the best technique to be used by the planter and one problem to be considered in using the technique.



Answer:
(a)(i)

K: Chromatid
M: Spindle fibre

(a)(ii)
Cell R: Metaphase
Cell S: Metaphase I

(b)
8 daughter cells

(c)(i)



(c)(ii)
1. Testis
2. Ovary

(c)(iii)
6 chromosomes

(d)
Radioactive rays destroy the cells, so the rate of mitosis is controlled.

(e)
– Cloning / culture tissue
– All the clones are easily attacked by diseases because all the clones have the same resistance towards diseases.


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