1.	Near the middle of pregnancy in humans, the placenta begins to secrete a hormone called corticotrophin-releasing hormone (CRH). CRH influences the production of hormones which stimulate the development of the fetus.
	A study was carried out to determine if levels of CRH were correlated with the timing of the baby’s delivery. Blood samples were taken from 500 women during their pregnancies and the concentration of CRH was measured. The women were then divided into three groups according to whether their baby was delivered prematurely, at full-term (about 40 weeks) or late.
 
	The graph below shows how the concentration of CRH varied in the mothers’ blood (maternal blood) in each of the three groups during pregnancy.

[Source: R Smith, Scientific American, (March 1999) Pages 68–75]
 
(a)	Outline how the concentration of CRH in the blood changes during the pregnancies of women who delivered prematurely.
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(2)

(b)	Compare how the concentration of CRH changes during the pregnancies of women who delivered late with those that delivered at full-term.
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(2)
 
(c)	Measure the difference in CRH concentration at 30 weeks between the women who delivered prematurely and those that delivered at full-term.
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(1)
 
(d)	Suggest how knowledge of the CRH concentration in maternal blood might be used by doctors monitoring pregnancies.
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(2)
 
	The Western spadefoot toad (Scaphiopus hammondii) lives in desert areas in California and lays its eggs in pools formed by rain. When the egg first hatches, its body form is referred to as the tadpole stage. At some point, it undergoes metamorphosis (a change in body form) to develop into the adult toad.
	If the pools where the eggs have been laid shrink due to a lack of rain, the tadpoles quickly develop into small adult toads. If there is sufficient rain and the pools persist, the tadpoles develop more slowly and grow large before developing into adult toads.

(e)	Suggest how undergoing metamorphosis at different times in response to water levels helps the survival of the toad.
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(3)
 
	It has been suggested that CRH control of development might have evolved in amphibians long before mammals appeared. In toads, increase in CRH concentration leads directly to an increase in the level of the hormone thyroxine and indirectly to an increase in corticosterone levels.
	An experiment was carried out to determine what hormones might be involved in triggering development in response to pond drying. Tadpoles were raised in a constant high water level environment. They were then divided into two groups. One group was transferred to a tank containing 10 dm3 of water – a high water environment. The other group was transferred to a tank of the same size containing only 1 dm3 of water – a low water environment. The concentrations of thyroxine and corticosterone were measured in each group. The results are shown below.

[Source: R J Denver, General and Comparative Endocrinology, (1998), 110, pages 326–336]

(f)	Compare the concentrations of thyroxine and corticosterone in the two groups.
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(2)
 
(g)	Predict how the concentration of CRH would be different in the two groups.
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(1)
(Total 13 marks)

2.	Discuss the ethical issues of in vitro fertilisation (IVF) in humans.
(Total 8 marks)

3.	Draw a labelled diagram of an adult male reproductive system.
(Total 4 marks)

4.	Outline the process of in vitro fertilization (IVF).
(Total 6 marks)

5.	Draw a labelled diagram of the reproductive system of a human female.
(Total 6 marks)

6.	Explain how hormones control the menstrual cycle in human females.
(Total 8 marks)

7.	The diagram below shows the male reproductive system.

[Source: Adapted from J Vellacott and S Side, Understanding Advanced Human Biology, (1998), Hodder and Stoughton, page 281]
 
(a)	State the names of I and II.
I:	...........................................................................................................................
II:	...........................................................................................................................
(2)

(b)	Discuss the ethical issues of family planning and contraception.
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(4)
(Total 6 marks)

8.	Outline early embryo development in the human until implantation in the uterus.
(Total 4 marks)

9.	In the menstrual cycle in humans, which hormone causes the wall of the follicle to develop after ovulation and to secrete more progesterone?
A.	Estrogen
B.	FSH
C.	LH
D.	Oxytocin
(Total 1 mark)

10.	How does the amniotic fluid help the fetus during pregnancy?
I.	Supplies food to allow the fetus to grow rapidly
II.	Supports the fetus so that no part of it is under excess pressure
III.	Protects the fetus by acting as a shock absorber
A.	I and II only
B.	I and III only
C.	II and III only
D.	I, II and III
(Total 1 mark)

11.	The umbilical cord connects the fetus to the mother during pregnancy. The following is a drawing of a cross section of an umbilical cord.

(a)	(i)	Annotate the drawing above to show an artery.
(1)

(ii)	Briefly explain the structural features which lead to your choice above.
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(2)
 
(b)	The umbilical vein carries substances from the mother to the embryo. State two of these substances.
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(2)
 
(c)	The umbilical cord is joined to the placenta. Throughout pregnancy the placenta secretes hormones. Changes in the levels of these hormones control the timing of birth. Oxytocin, a hormone which is not produced by the placenta, is also involved in the process of birth. Briefly describe the role of oxytocin.
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(2)
(Total 7 marks)

12.	Which organ secretes FSH (follicle-stimulating hormone)?
A.	Ovary
B.	Testis
C.	Pituitary gland
D.	Placenta
(Total 1 mark)

13.	Which of the following occur(s) at birth in the mother’s body?
I.	Increase in oxytocin
II.	Increase in uterine contractions
III.	Increase in levels of progesterone
A.	I only
B.	I and II only
C.	II and III only
D.	I, II and III
(Total 1 mark)

14.	Which of the following is regulated by positive feedback?
A.	Blood sugar
B.	Temperature
C.	Oxytocin levels
D.	Progesterone levels
(Total 1 mark)

15.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw and label a generalized prokaryotic cell as seen under the electron microscope.
(4)
(b)	Outline the process of meiosis.
(6)
(c)	Explain the role of the following hormones in the menstrual cycle: estrogen, progesterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH).
(8)
(Total 20 marks)

16.	How does fertilization differ from copulation?
A.	Fertilization always produces a zygote.
B.	Only fertilization involves gametes.
C.	Fertilization is a conscious event.
D.	Fertilization can spread HIV.
(Total 1 mark)

17.	Women should periodically have a Pap smear test performed to detect cervical cancer. Which letter indicates the cervix in the diagram below?

(Total 1 mark)

18.	Which of the following outlines the roles of the two hormones oxytocin and progesterone during childbirth?
	Oxytocin	Progesterone	
A.	causes uterine contraction	level rises allowing oxytocin
production	
B.	level falls allowing progesterone
production	causes uterine contraction	
C.	stimulates estrogen production	level falls allowing oxytocin
production	
D.	causes uterine contraction	level falls causing oxytocin
production	

(Total 1 mark)

19.	The diagram below shows the human male reproductive system and associated organs.

	Which of the labelled structures indicate the bladder, prostate and urethra?
	Bladder	Prostate	Urethra	
A.	Y	X	Z	
B.	X	Y	Z	
C.	Z	X	Y	
D.	X	Z	Y	
(Total 1 mark)

20.	Human sperm and eggs both consist of single cells. What is a difference between them?
A.	Sperm have more chromosomes than eggs.
B.	Eggs have more chromosomes than sperm.
C.	Sperm have a larger surface area to volume ratio than eggs.
D.	Eggs have a larger surface area to volume ratio than sperm.
(Total 1 mark)

21.	Do the levels of progesterone and FSH increase or remain low during the first few days of the menstrual cycle?
A.	Progesterone and FSH both remain low.
B.	Progesterone remains low but FSH increases.
C.	Progesterone increases but FSH remains low.
D.	Progesterone and FSH both increase.
(Total 1 mark)

22.	What are the levels of the hormones estrogen, progesterone, LH and FSH during the menstrual cycle at the time of ovulation?
	Estrogen	Progesterone	LH	FSH	
A.	High	Low	High	High	
B.	High	High	Low	High	
C.	Low	High	High	Low	
D.	Low	Low	Low	Low	
(Total 1 mark)

23.	(a)	List two roles of testosterone in males.
1.	..........................................................................................................................
2.	..........................................................................................................................
(1)

(b)	A boy inherited red-green colour-blindness from one of his grandfathers. Deduce, giving your reasons, which of his two grandfathers was also colour-blind.
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(3)
(Total 4 marks)

24.	(a)	concentration rises throughout pregnancy;
the rise is exponential / levels rise significantly later in pregnancy;	2
Award [0]for a description which only implies a rise.
 
(b)	the CRH concentration is lower in late deliveries / higher in full-term deliveries; differences greater / become more pronounced later in the pregnancy;
both rise gradually;	2 max
 
(c)	57 pmol dm–3 of plasma; (± 3)	1
Value and unit needed for [1].
 
(d)	high concentration would indicate women at high risk of premature delivery;
low concentration would indicate women at risk of going past term / delivering late; concentration could be used to indicate when delivery is imminent;
concentration might indicate special precautions or medical technique needed;
(eg reduce physical activity of mother or provide special incubator for likely
premature birth or induce labour for past term mothers);	2 max
 
(e)	low water:
toads can mate earlier as conditions dry;
toads can move to larger ponds;
tadpole / organism cannot survive in absence of water;
 
	high water:
larger toads more resistant to predation;
larger toads more attractive to mates;	3 max

(f)	concentrations of thyroxine and corticosterone higher in 
low water group / vice versa; 
greater difference in thyroxine concentration / less 
difference in corticosterone
concentration between the two groups;
in both groups thyroxine concentrations are higher than 
corticosterone concentrations;	2 max
Comparisons need to be made between the two hormones in the high water environment / low water environment.
 
(g)	CRH levels would be higher in the low water group / vice versa;	1
[13]

25.	Arguments against (IVF):
fertilized egg has potential to become a person / some view a fertilized
egg as having special status;
IVF requires the production of multiple embryos;
fate of extra embryos is ethical concern;
ethics of long-term storage;
stem-cell research is blurring issue as other cells now have the 
possibility of becoming a person;
procedure may result in multi-embryo pregnancy which places stress
on the family resources / unwanted children;
issues of equity of access / expensive;
high rates of failure;
ownership / responsibility for stored embryos an issue;
religious opposition / playing God;
 
	Arguments favouring (IVF):
only way some couples can have children / helps infertile couples;
allows for genetic screening;
allows for surrogate mothers;	8 max
For full marks at least two of the points should include the counter-argument,
otherwise [6 max].
[Plus up to [2] for quality]
[8]

26.	Award [1] for each two of the following structures clearly drawn and correctly labelled. Connections between organs must be correct for full marks.
penis;
scrotum;
prostate gland;
sperm duct;
urethra / urinary tract;
seminal vesicle;
bladder;
testes;
epididymis;
sperm duct / Vas deferens;
Cowper’s gland;
seminiferous tubules;
erectile tissue;
[4]

27.	(IVF) is fertilization outside body / "in glass";
(drug) stops normal menstrual cycle;
(inject FSH) to stimulate ovaries / stimulate production of eggs;
(HCG) matures the follicles;
eggs are removed from follicles / ovaries / mother;
male provides sperm / sperm donor;
washing / capacitation of sperm;
eggs are mixed with sperm;
2–3 embryos are implanted into uterus;
pregnancy test is done to see if implantation / pregnancy has occurred;
[6]

28.	Award [1] for each of the following structures, clearly labelled and 
drawn in the correct position relative to the other organs, up to [6 max].
	ovary;
oviduct / fallopian tube;
uterus;
cervix;
vagina;
vulva / labia;
clitoris;
endometrium;
[6]

29.	FSH stimulates the development of follicles;
FSH stimulates estrogen secretion (by the developing follicle);
estrogen stimulates the repair of the uterus lining;
estrogen stimulates LH secretion;
LH causes ovulation;
LH causes the development of the corpus luteum;
LH causes secretion of progesterone;
progesterone causes thickening of the uterus lining / prepares uterine 
lining for implantation;
progesterone / estrogen inhibits the secretion of LH / FSH;
falling progesterone levels at the end of the cycle allow FSH production / menstruation;
feedback control;	8 max
(Plus up to [2] for quality)
[8]

30.	(a)	I: the prostate gland;
II: the urethra;	2
 
(b)	ethical arguments against: [3 max]
not natural;
against religious teaching;
allows casual sex / multiple partners / promotes promiscuity;
zygotes / embryos killed (by IUDs) / (some) contraceptive pills;
contraceptive pill / methods other than condoms encourage spread of STDs;
IUD / contraceptive pills have side effects / named side effect;
 
	ethical arguments for: [3 max]
helps to control the human population;
prevents birth of unwanted children / reduces abortion / 
reduces number of single parent families;
freedom of choice / women can pursue careers;
condoms prevent spread of STDs / HIV / AIDS;
economic reasons / cannot afford children / cost to society;	4 max
[6]

31.	fertilized egg called a zygote;
cell divides by mitosis;
early divisions of zygote result in reduction in quantity of
cytoplasm per cell / no increase in overall size;
first divisions occur while zygote in fallopian tube / oviduct;
several divisions result in the formation of a bundle of cells called a morula;
further divisions result in a hollow ball of cells /
fluid filled ball of cells / blastocyst;
implantation occurs up to seven days after fertilization;
[4]

32.	C
[1]

33.	C
[1]

34.	(a)	(i)	one artery labelled	1

(ii)	thick wall (relative to oval structure / vein);
thickness in wall because of fibres (collagen, elastic, muscle);
narrow lumen (relative to oval structure / vein);
Do not accept inside is smaller for narrow lumen
umbilical cord has two arteries (and one vein);	2 max
 
(b)	glucose / carbohydrates;
amino acids;
do not accept “nutrients”
antibodies;
water;
fats / fatty acids and glycerol;
oxygen;
minerals / vitamins;	2 max

(c)	oxytocin produces uterine contraction;
regulated by positive feedback;
more contractions produce more oxytocin;
oxytocin stimulates milk ejection (in lactation);	2 max
[7]

35.	C
[1]

36.	B
[1]

37.	C
[1]

38.	(a)	Award [1] for any of the following clearly drawn and correctly labelled.
	Award [2 max] if two or more eukaryotic structures are given and if a nucleus
is included award [0].
cell wall / capsule / slime wall / layer;
plasma / cell membrane;
mesosome,
cytoplasm;
ribosomes;
nucleoid / naked DNA;
flagella;
pili;
plasmid;
size stated 1 to 10 μm;	4 max
 
(b)	two cell divisions / reduction-division / diploid to haploid / meiosis I
and meiosis II;
produce four (haploid) cells;
for production of sex cells / gametes / spores;
daughter cells are different from parent cells;
homologous chromosomes / two chromatids pair up;
line-up on equator;
(spindle fibres) pull homologous chromosomes to opposite poles;
two haploid cells are formed;
second division / like mitosis, separates chromatids to opposite poles;	6 max
Accept any of the above points if clearly explained in a
labelled diagram.
 
(c)	FSH stimulates (in first few / five days) follicle development (in ovary);
(FSH stimulates) follicles to secrete estrogen, (positive feedback);
low levels of estrogen initially inhibit FSH (and LH) secretion;
	rapid increase in estrogen stimulates FSH / LH production, (positive
feedback);
estrogen also starts to repair / thicken endometrium / uterine lining;
LH stimulates ovulation;
	LH causes follicle to produce less estrogen (negative feedback) / more
progesterone (positive feedback);
LH stimulates follicle to become corpus luteum;
	corpus luteum secretes (more estrogen and) large level of progesterone
(positive feedback);
	estrogen and / or progesterone stimulate thickening of endometrium / 
uterus lining;
	estrogen and / or progesterone inhibit FSH and LH secretion (by
negative feedback);
	estrogen and / or progesterone levels fall after day 21-24 if no embryo
 / fertilization;
	lower concentrations of estrogen and / or progesterone allow
disintegration of endometrium / menstruation occurs;
FSH secretion begins a new cycle;	8 max
Award [6 max] if only three hormones are explained.
 
(Plus up to [2] for quality)
[20]

39.	A
[1]

40.	C
[1]

41.	D
[1]

42.	B
[1]

43.	C
[1]

44.	B
[1]

45.	A
[1]

46.	(a)	Award [1] for two of the following
pre-natal development of male genitalia;
development of male secondary sexual characteristics / name of
specific characteristic;
maintenance of sex drive;	1 max
 
(b)	red-green colour-blindness is a sex-linked character / gene located on
X-chromosome;
boy inherits X chromosome from mother, only inherits Y chromosome
from father;
boy’s mother must have been carrying the gene;
he inherited it from mother’s father / maternal grandfather;	3 max
[4]