Sexual Reproduction in Humans (Cambridge O Level Biology)

Complete the sentences by stating the part of the human body that produces male gametes and the part that produces female gametes.

Male gametes are produced by the ........................................................................

Female gametes are produced by the ...................................................................

Fig. 1 represents the early stages in the development of a female embryo.

Fig. 1

[3]

Define the term sexual reproduction.

Fig. 1 shows some organs in the body of a man.

Fig. 1

Complete Table 1 by writing in the names of the parts labelled A to D in Fig. 1. 

Table 1

[4]

State the function of the scrotum.

Fig. 1 is a diagram of the human female reproductive system.

Fig. 1

Complete Table 1 by stating the letter from Fig. 1 that identifies the structure where each process occurs.

Table 1

[3]

State the name of the part of the female reproductive system labelled S in Fig. 1.

[1]

Extended Only

Fig. 2 is a diagram of a human sperm cell.

Fig. 2

Write the formula that would be used to calculate the magnification of the diagram.

[1]

The actual length of the sperm cell in Fig. 2 is 0.055mm.

Convert this value to micrometres (μm).

Space for working.

___________ µm  [1]

Explain why the nuclei of sperm cells differ from those of other cells in the male.

Explain the roles of the flagellum, the mitochondria and the acrosome in sperm cells.

Explain why the sex of a child is determined by its father.

Glycogen is a storage carbohydrate in animals. Glycogen is made from glucose.

[2]

A fetus needs glucose to make glycogen. 

Describe how a fetus obtains glucose.

Fig. 1 shows the concentration of glycogen in the fetus of a domestic cat during pregnancy and immediately after birth.

Fig. 1

Hormones stimulate changes in the concentration of glycogen in the fetus.

Define the term hormone.

[3]

Calculate the percentage increase in the glycogen concentration in the fetus between day 10 and birth in Fig. 1.

Give your answer to the nearest whole number.

Show your working.

Describe the changes in glycogen concentration shown in Fig. 1 and explain how hormones in the fetus cause these changes.

Use data from Fig. 1 to support your answer.

[6]

Polycystic ovary syndrome (PCOS) is a condition that commonly occurs in women of reproductive age. It is characterised by hormonal imbalances that affect the menstrual cycle of women with this condition.

Fig. 1 compares the levels of FSH and LH in a normal menstrual cycle with the levels seen in the cycle of a woman with PCOS.

Fig. 1

Use the information in Fig. 1 to explain the effect that PCOS would have on the ovaries of a woman.

[4]

Women with PCOS will often struggle with infertility.

Suggest a possible reason for this.

Fig. 2 shows changes in the thickening of the uterus wall lining in two women X and Y.

Fig. 2

Suggest an explanation for the difference in the thickness of the uterus wall lining between woman X and Y in Fig. 2.

Outline how the levels of LH and progesterone will differ between woman X and Y during the next calendar month (assume a normal menstrual cycle for woman Y).