Download public exam_reproduction in humans

ECF Saint Too Canaan College
Biology public exam exercise
Reproduction in humans
Name: ___________________
Class: ______ (
)
Date: _____________________
CE 1999_I_Q.3(c)
1. (a) State the function of the uterus during the birth of a baby.
(3 marks)
(b) The graph below shows the changes in the thickness of the uterine lining of a woman in a
certain month:
State the period (W, X, Y or Z) during which sexual intercourse might have a good chance of
leading to pregnancy. Explain your answer.
(4 marks)
(c) One method of contraception is to avoid having sexual intercourse during the period stated in
the answer to (b). Suggest two reasons why this method of contraception may not be so
reliable.
(2 marks)
Bio_public exam_reproduction in humans
P.1
CE 2000_I_Q.1(a)(i)(iv)(v)
2. The diagram below outlines a clinical test used to examine whether a human foetus has any
abnormality in its chromosomes:
(a)
The cells of A and the cells of the foetus have the same genetic composition. How would
you explain this?
(2 marks)
(b)
As the uterine wall may be stimulated to contract when removing cells from A, what would
be the risk associated with this test?
(c)
(1 mark)
State two differences between the blood entering the foetus and that leaving the foetus.
(2 marks)
Bio_public exam_reproduction in humans
P.2
CE 2003_I_Q.2(b)
3. The cartoon below shows foetus crying for help inside the mother’s body:
(a) Smoking during pregnancy is hazardous to the foetus. The foetus may be affected in a
number of ways, such as a reduced supply o oxygen and the entry of toxic chemicals.
(i) Suggest an explanation for the reduced oxygen supply to the foetus.
(2 marks)
(ii)
Using a flowchart, show the route by which nicotine in cigarette smoke is transported
from the mother’s lungs to the foetus. Indicate only the major organs and blood vessels
involved.
(3 marks)
(b) (i)
An early sign of the birth process is the breaking of the amnion. What is the
significance of this event in the birth process?
(2marks)
(ii)
Describe what happens afterwards that leads to the birth of the baby.
(3marks)
Bio_public exam_reproduction in humans
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CE 2004_I_Q.2(a)
4. The table below shows the average number of pregnancies for women adopting different
contraceptive methods:
(a) The use of condoms and diaphragms are based on the same principle in bring about
contraception. What is this principle?
(1 mark)
(b) How can an IUD prevent pregnancy to occur?
(1 mark)
(c) (i)
Explain the biological basis of the rhythm method.
(3 marks)
(ii)
Why does this contraceptive method have a high rate of failure?
(1 mark)
(d) Even though some couples do not use any contraceptive methods and have regular
intercourse, the wives fail to become pregnant. Suggest two reasons for this.
(2 marks)
Bio_public exam_reproduction in humans
P.4
AL 2002_I_Q.4(b)
5. Describe how the mammalian foetus obtains amino acids from proteins in the maternal diet.
(5 marks)
AL 2004_I_Q.8(a)(i)
6. The diagram below shows a mammalian sperm with its mitochondria localized in the region
shown:
Relate the location of the mitochondria to their function.
(2 marks)
Bio_public exam_reproduction in humans
P.5
ECF Saint Too Canaan College
Biology public exam exercise – Reproduction in humans answer
1.
(a)
The muscular wall of the uterus contracts
rhythmically and powerfully
to push the baby out of the uterus.
1
1
1
(b)
Period X
Ovulation occurred around period X
Thus fertilization might occur after sexual intercourse
Besides, around this period, the uterine lining is ready for the implantation of the
embryo.
1
1
1
1
(c)
The day of ovulation may vary from cycle to cycle.
The duration of the menstrual cycle of a woman may vary.
1
1
(9)
2.
(a)
The cells of A and the cells of the foetus are formed by mitosis
of the zygote.
1
1
(b)
The foetus may be expelled out of the uterus / miscarriage
1
(c)
Blood from A to the foetus has
higher oxygen content.
higher nutrient content.
lower carbon dioxide content.
lower urea content.
1
1
(1)
(1)
(5)
3.
(a)
(i)
Tar in cigarette smoke deposits on the surface of the air sacs in the mother’s
lungs.
As a result, less oxygen can be absorbed into the mother’s blood. Hence,
1
1
reducing the oxygen supply to the foetus
(b)
(ii)
(mother’s lung)  pulmonary vein  heart  aorta  artery to uterus 
placeta  umbilical vein  (foetus)
6 x 0.5
3
(i)
The results in the discharge of the amniotic fluid
which lubricates the passage of the foetus through the vagina.
1
1
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P.6
3.
(b)
(ii)
The cervix continues to dilate.
The uterus and the abdominal muscles contract strongly
to expel the foetus through the vagina.
1
1
1
(10)
4.
(a)
Both of them are based on the use of a barrier / prevent the sperms from meeting the
1
egg.
(b)
IUD prevents the implantation of the embryo.
(c)
(i)
(ii)
(d)
1
Egg and sperms are viable for only a few days once they are released.
The rhythm method is to avoid sexual intercourse around the time of
ovulation,
1
1
so that sperms and egg will have no chance of meeting each other.
1
Because it is hard to predict the time of ovulation accurately.
1
Time of intercourse does not necessarily fall in the period around ovulation.
Gametes produced may not be viable / may be defective.
1
1
(8)
5.
- maternal digestion: protease breaks down proteins to amino acids / peptides (1), in
1
stomach and small intestine (1)
- absorbed into the maternal blood stream at the ileum (1)
- amino acids are carried via veins to hearts, then along artery to uterine wall (1)
- amino acids diffuse across the placenta into foetal blood circulation (1)
1
1
1
1
(5)
6.
- mitochondria close to the tail (1)
- provide energy for motility of the tail of sperm (1)
1
1
(2)
Bio_public exam_reproduction in humans
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