O-LevelBiologyCoordination & Response5090/22 · Oct/Nov 2021 · Q49 Marks

A study investigated the probability of pregnancy resulting from sexual intercourse on specific days of the menstrual cycle. The graph shows the results of this study. [Figure 4.0]

(a)(i)The study shows a probability of 20% that sexual intercourse three days before ovulation will result in pregnancy. State how many times more likely pregnancy is if sexual intercourse takes place two days later.[1]
(a)(ii)Explain the role of named hormones in the menstrual cycle during the days investigated by this study.[5]
(b)The diagram shows a fetus developing in the uterus of a pregnant female human. [Figure 4.1] Name structure X and describe the functions of this structure. name functions[3]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.

[1] 2 / twice as likely / doubles ;
[5] FSH ; (only if FSH stated) growth / maturation + of follicle ; (only if FSH stated) in ovary ; oestrogen ; (only if oestrogen stated) repair AW of uterus + wall / lining ; LH ; (only if LH stated) ovulation AW ;
[1] placenta ;
[2] any two from diffusion; oxygen / glucose / antibodies + from mother / to fetus AW ; carbon dioxide / urea + from fetus AW / to mother; from blood + to blood ; produces progesterone ;

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