Question 1:
Diagram 1 shows the schematic diagram of sex determination in human being.


(a) In Diagram 1, complete the sex chromosomes in gametes K and L. [2 marks]

(b) What is gamete L? [1 mark]

(c) State process B. [1 mark]

(d) State the sex of offspring M. [1 mark]

(e) Based on Diagram 1, state the percentage to get a baby boy. [1 mark]

Answer:
(a) K : X, L : Y

(b) Sperm

(c) Fertilization

(d) Girl

(e) 50%
 

Question 1:
Diagram 1 shows the stages of cell division.

(a)(i) Name the type of cell division as shown in Diagram 1. [1 mark]
 
(ii) Give reason to your answer in (a)(i). [1 mark]

(b) Arrange the stages of cell division P, Q, R and S in a correct sequence in the boxes given. [1 mark]

(c)(i) Name structure W. [1 mark]

(ii) How many structures W in each cell at stage P? [1 mark]

(d) What happens to structure W if exposed to radioactive radiation? [1 mark]


Answer:
(a)(i) Mitosis

(a)(ii) The daughter cells contain the same number of chromosomes as the parent cell.

(b)

(c)(i) Chromosome

(c)(ii) 46

(d) Mutation may occur

Question 2:
Diagram 2 shows a process of cell division. Chromosomes at stage B are not shown.

(a)(i) Name the process shown in Diagram 2. [1 mark]
 
(ii) State the importance of the process in (a)(i). [1 mark]

(b)(i) During stage C, the chromosomes line up on the equator.
   What happens to the chromosomes during this stage? [1 mark]
 
(ii) What is the effect of the process in (b)(i) on the offspring? [1 mark]

(c) In Diagram 2, draw the chromosome at stage B. [1 mark]

(d) How many daughter cells are produced at the end of Division II in Diagram 1? [1 mark]


Answer:
(a)(i) Meiosis

(a)(ii) Production of gametes

(b)(i) Crossing-over

(b)(ii) Variations

(c)

(d) 4 daughter cells are produced

Organism	Chromosomes number
Housefly	12
Onion	16
Frog	26
Apple	34
Human	46
Potato	48
Cow	60