Fertilisation occurs when the .....(A)..... of the sperm cell fuses with the.....(B) ..... of the

..... (C) ..... .

2 State the differences between the male gametes and the female gametes with regard to

(a) their size; (b) their structure, (c) their relative numbers.

3 Before fertilisation can occur, the sperms have to travel from the testes to meet an ovum in the female organs. Using the list below, name the organs, in the correct order, through which the sperms will have to pass.

uterus, sperm duct, oviduct, urethra, cervix, vagina

4 (a) Explain what is meant by ovulation.

(b)How often does it occur in humans?

5 Explain why the chance of fertilisation in humans is restricted to only a few days each

month.

7 Blood from the fetus circulates through the placenta.

(a) What substances pass (i) from the maternal to the fetal blood, (ii) from the fetal to the

maternal blood?

(b) By what means is the fetal blood circulated through the placenta?

8 What is the function of the umbilical cord?

9 What are the possible effects on the fetus if, during pregnancy, the mother (a) smokes,

(b) catches rubella?