2. Two types of Reproduction
1. Asexual 2. Sexual
Offspring are produced
by a single parent;
No sperm and egg
needed
Involves the fusion
of two cells, one
from a male and the
other from a female

3. Which type of reproduction produces
clones?
Asexual reproduction.
Offspring are genetically identical

4.  Fertilisation is the fusion of the
male and female gamete nuclei to
form a zygote
 Zygote is the first cell that forms after
fertilisation

5. hermaphrodite
 have both male and
female sex organs Tapeworm
EarthwormSnail Flower

6. Fertilisation can be:
a) Internal:
 in reptiles, birds & mammals
b) External:
 in most fish & amphibians

7. Why is internal fertilisation essential
amongst land animals?
No water in the animal’s immediate environment
to carry the sperm cells to the eggs

8. A cod [fish] lays millions of eggs in one year but
a rabbit produces only a few thousand.
Question

9. External fertilisation in fish:
 Not all eggs are fertilised
 Young ones are not protected by the mother’s
body

10. Table 1 Comparison of sexual and
asexual reproduction.
ASEXUAL SEXUAL
1) One parent needed
Two parents needed, a male
and a female
2) No gametes required
(sex cells)
Gametes required
3) Offspring are
genetically identical
(clones)
Offspring are not genetically
identical

11. Table 1 Comparison of sexual and
asexual reproduction.
ASEXUAL SEXUAL
4) Only one individual is
needed to colonise a
new area
A male and a female are
needed
5) A fast process A slow process
6) Always increases the
population
Does not always increase the
population
7) Very common among
plants and simple
animals
Almost all animals and
plants

12. ASEXUAL SEXUAL
Advantage:
a good characteristic
shows up in all the
offspring
Advantage:
new varieties are produced,
which may be more able to
adapt to the new
environment
Disadvantage:
a defect in the parent
shows up in all
offspring ; no variation
occurs
Disadvantage:
excellent individuals cannot
give identical offspring

13. Gonads & Gametes
MALE FEMALE
Gonads [sex
organs]
Testes Ovaries
Gametes
[sex cells]
Sperm Ovum / egg
Gametes are produced by a type of cell
division called:
Meiosis

14. The Male Reproductive System
(scrotal sac)
(vas deferens)

15. The male Excretory System

16. The male Excretory & Reproductive
Systems
bladder
ureter
sphincter muscle
prostate gland
urethra
testis
scrotum
penis
sperm duct

17. Functions of the testes:
1. Produce sperms
2. Produce the sex hormone testosterone

18. Function of the epididymis:
Stores sperms for 2-3 months
[6m long but
coiled = 3.8cm]

19. Function of the sperm duct:
 Stores sperms
 A passageway for
sperms from
epididymis to
urethra

21. Scrotum
 holds testes outside the body
 temperature of about 1-2C lower than
body temperature
 sperms only develop properly inside the
testes at a slightly cooler temperature
 heat can cause
infertility

22.  ejaculation
 is the expulsion of semen from the
urethra
 copulation (sexual intercourse / mating)
 is when the man's penis is inserted into
the woman's vagina and excited until
orgasm and ejaculation occur

23. Semen = fluids + sperms
Semen from a
bull Semen from
a dog

24. Human semen contains
 90-600 million sperms in 3 cm3 of ejaculate
or semen
Normal sperm
count
Low sperm
count
Why are sperms produced in large numbers?
Increase chance
for fertilisation

25. Fluids in semen are released from the:
 seminal vesicles
 prostate gland

26.  semen contains:
 alkali
 sugars
 proteins
Urine is
ACIDIC.
 Functions of the fluid:
1. the fluid keeps the sperms alive
2. helps them to swim vigorously

27. Fig. 2 Ovum structure.

28. Fig. 3 A spermatozoon.

29. Function of the TAIL:
to swim towards the
ovum

30. Function of the NUCLEUS:
Fuses with ovum nucleus
to produce the offspring

31. Function of the MITOCHONDRIA:
releases energy for tail to move

32. releases enzymes to penetrate ovum
Function of the ACROSOME:

33. [Old term]

35. Question: JUNE 1998
What are the main differences between a
sperm and an ovum? (4 marks)
SPERM OVUM
1. Small Large
2. Has a tail No tail
3. Has an acrosome No acrosome
4. No food reserves Has food reserves

36. Question: SEP 2006
The female egg and the male sperm are two
specialized cells. Compare the egg and the
sperm in each of the following characteristics:
i) size (2 marks)
ii) numbers produced (2 marks)
iii) movement. (2 marks)

37. Fig. 4 The human female reproductive
system.
Endometrium
(uterus lining)
Uterus
Cervix
Vagina
Ovary
Fallopian tube
(oviduct)
‘womb’ – common
term for uterus

38. TWO separate openings
in female.
Vagina
Urethra

39. Ovulation
 the release of an ovum from the ovary
 occurs once every 28 days
Developing follicles
Mature follicle
Corpus luteum /yellow body
Ovulation
Graafian follicle

40. Ovulation caught on camera: takes 15
minutes
Ovum
Follicle
Ovary
Surgical
instrument

41. An ovum develops inside a:
 fluid-filled Graafian follicle

42. What happens to an egg if it is
not fertilised?
If not fertilised within a day or so
it will die

43. Vagina
Cervix
Ovary
Fallopian
tube
Ovum
Uterus
Sperm cells
deposited
in vagina
Fertilisation

44. What happens during menstruation?

45. Functions of:
Ovary:
1. Produces ova (eggs)
2. Produces sex hormones

46. Functions of:
Fallopian tubes:
1. Pathway for sperms to reach the ovum
2. Fertilisation occurs inside it
3. Has cilia and is muscular to move
ovum towards uterus

47. Functions of:
Uterus:
1. An embryo attaches to the uterus lining
(becomes implanted)
2. An embryo develops inside it
3. Muscles in uterus contract to give birth
implantation

48. Functions of:
Cervix:
1. To allow menstrual blood to flow into the
vagina
2. To direct the path of sperm into the uterus so
fertilisation may occur
3. Becomes blocked by mucus when pregnant to
avoid infections

49. Functions of:
Vagina:
1. Penis is inserted to deposit semen
2. Passageway for menstrual blood
3. Serves as the birth canal

50. Side view of female reproductive
system

51. Question: MAY 2012
Describe the role of each of the following in a
female:
i) vagina; (3)
ii) oviduct; (1)
iii) ovary; (3)
iv) uterus. (2)

52. Question: MAY 1999
Trace the path of the male gamete, from its site
of origin until it reaches the female gamete in a
mammal.
Diagrams are not expected, but detail of how
and what helps the male gamete to reach the
female gamete at the site where fertilisation
usually takes place, are important.
(10 marks)

53. Testis, epipidymis, sperm duct, urethra
Top of vagina, cervix, uterus, fallopian tube

54. Question
What are the functions of the following?
MALE FEMALE
UTERUS
URETER
URETHRA

55. MALE FEMALE
UTERUS Absent Where embryo
develops
URETER
URETHRA

56. MALE FEMALE
URETER Urine flows
from kidney to
bladder
Urine flows
from kidney to
bladder

57. MALE FEMALE
URETHRA

58. MALE FEMALE
URETHRA Semen &
urine flow to
exterior
Urine flows to
exterior

59. How long does an ovum & a sperm
survive once released?
 12–24 hours  1-3 days in the
presence of fertile
mucus

60. How long is the fertile period?

61. Can you predict with certainty when
the fertile period is going to be?
NO

62. In a short cycle of 21 days,
ovulation will occur around day 7
and there will be no pre-ovulatory infertile days.

63. Sexual Development
Puberty

64. Puberty
 is the stage of the beginning of sexual maturity
In girls:
12-15 years
In boys:
13-17 years

65. Primary sexual characteristics
 appear in the growth and enlargement of the
reproductive organs
 In boys:
 sperm production
 ejaculation starts
 In girls:
 ovulation starts

66. Secondary sexual characteristics
 appear as changes in body shape and
appearance

67. Secondary sexual characteristics
 Boys:
1. grow hair on the face, armpits
and pubic regions

68. Secondary sexual characteristics
 Boys:
2. voice deepens
3. limb and chest muscles develop

70. Secondary sexual characteristics
 girls:
1. develop hair on the armpit and pubic
regions
2. pelvic girdle widens

71. Secondary sexual characteristics
 girls:
3. breasts develop
4. fat deposits under the skin

72. Sex hormones are:
 testosterone in males
 secreted by:
 oestrogen in females
 secreted by:

73. Menopause
Occurs in females [45-50 years]
What happens:
 ovaries stop producing eggs
 menstrual periods stop
Reason for menopause:
 female stops producing sex hormones in
sufficient amounts

74. What about males?
 go on producing sperm throughout life
 however the amount of testosterone
gradually falls

75. The
Menstrual
Cycle
The first day of menstruation is day 1 of the cycle.

76. Fig. 5 Development of follicles inside
the ovary.
(Yellow body)

77. The menstrual cycle
 is controlled by 4 hormones
1. FSH (follicle stimulating hormone)
2. LH (luteinising hormone)
3. Oestrogen
4. Progesterone

78. Where is each hormone produced?
1. FSH
2. LH
pituitary
gland

79. Fig. 6 Summary
of the main
events during
the menstrual
cycle.
3. Oestrogen
4. Progesterone

80. 3. Oestrogen 4. Progesterone

81. Control of the menstrual cycle
Hormone Function
FSH Causes ovary follicles to develop
LH
Causes ovulation; Causes corpus
luteum to form from follicle
Oestrogen
Causes repair of the uterus lining
before ovulation
Progesterone
Causes uterus lining to remain thick
after ovulation

82. Changes in uterus lining
Breaks down:
progesterone falls
Repaired:
oestrogen risesRemains thick:
progesterone
rises

83. Fig. 7
Changes in
hormones
during the
menstrual
cycle.

84. Changes which occurred in the thickness of the
lining of the uterus of a woman over 84 days.
With reference to the graph :
What took place during days 0 to 5 and days 28 to 33?
Menstruation

85. What event occurred on day 14 and day 42?
Ovulation

86. What event occurred shortly after day 42?
Pregnancy

87. Development and Pregnancy

88. Fig. 8 Fertilisation in oviduct.

89. Fig. 9 Formation and implantation of
embryo.

90. How is it possible for only ONE sperm
to penetrate the ovum?
 a fertilisation membrane forms around the
ovum to act as a barrier soon after a sperm
enters

91. Fig. 12 Embryo developing inside
uterus.

92. Fig. 12 Embryo developing inside
uterus.

93. The Placenta
 is shaped like a plate
 forms a close association between the
embryo and the mother

94. The Placenta has many Villi
 which stick into
blood spaces in
the wall of the
uterus
 the mother’s
blood circulates
through these
spaces

95. Fig. 11 The mother’s blood and that of the
foetus come close together in the placenta, but
do not mix.

96. Placenta
Glucose
Water
Salts
Amino
acids
Vitamins
Antibodies
Fatty acids
GlycerolUrea
Carbon dioxide

97. From embryo to foetus
a developing human from usually two
months after conception to birth

98. 8 week human foetus in palm of hand

99. Functions of the Placenta
1. produces the hormones oestrogen and
progesterone which stop menstruation and
prevent further eggs being produced by the
ovaries
2. allows food and oxygen to enter the foetus
3. helps to remove wastes like urea and carbon
dioxide from foetus

100. No mixing of blood at the placenta

101. Question: MAY 2010 IIB
List TWO ways how a sexually transmitted disease
(STD) can be transmitted from a pregnant mother
to the baby. (4)
1. Microbes can cross the placenta and infect the
baby before birth.
2. Microbes can be transmitted from mother to
baby during the delivery as the baby passes
through the birth canal.
3. During breastfeeding as is the case of HIV.

102. List TWO precautions that can reduce the
incidence of STDs. (4)
 Use of latex condoms for vaginal, anal and oral sex during
sexual contact/
 If you have an STD do not have sex until treated and cured/
 Avoid multiple sex partners/avoid casual
encounters/abstain (do not have sex)/ ask partner about
STD/regular check up
Any TWO or equivalent 4 marks
Do not award any mark if students mention contraception
(unless condoms are specifically mentioned)/ more sexual
education.
If students mention protection award 1 mark only.

103. Functions of the amniotic fluid:-
1. acts as a shock-absorber
2. keeps a constant temperature
3. keeps the embryo buoyant and free to grow
8 weeks

104. Twins
Identical twins
Fraternal twins
[non identical]

106. Question: SEP 2002
Copulation in humans may result in
fertilization. When fertilization occurs, it
may result in the formation of a single
zygote, identical twins, or fraternal twins.
Explain clearly what happens when
fertilisation results in the formation of:
(I) a single zygote; (II) identical twins; and
(III) fraternal twins. (2, 3, 2 marks)

107. Question: MAY 2012
1. List TWO physical changes that can
indicate that a female is pregnant. (2)
a. Breasts enlarge
b. Weight is gained

108. Question: MAY 2012
2. During the ninth month of pregnancy, the
female undergoes shortness of breath. Give
a reason for this observation. (1)
Uterus expands and lungs get compressed.

109. BIRTH

110.  gestation
 the period from fertilisation to birth
 labour
 the uterus begins to undergo occasional
contractions which become steadily
more frequent and powerful

111.  oxytocin
 a hormone made by the pituitary gland
What causes the uterus to contract?
Uterus between
contractions
Uterus during
contractions

112. Stages in birth

113. Afterbirth
 the placenta comes away from the wall of
the uterus and passes out of the vagina
TWINS!!

114. During pregnancy the cervix is
blocked by a mucus plug. Why?
 To prevent infection
 The mucus plug comes out as the cervix
dilates in labour or shortly before

115. Question: MAY 2011
6a.The following diagram shows the four stages of
the human menstrual cycle.
i) Briefly describe the changes taking place at
each stage 1, 2, 3 and 4. (10)

116. b. During gestation the placenta develops into a
large disc bearing many finger-like villi.
i) Explain how the placenta is joined to the foetus.
(1)
By means of the umbilical cord which contains
blood vessels.

117. ii) Explain why in dizygotic (non-identical) twins
there are two placentas. (3)
Two eggs/ova and two sperms were needed to
produce non-identical twins.
Each egg/ovum was fertilised and two separate
zygotes formed.
Each zygote produced a different individual.
iii)What happens to the placenta after birth? (2)
The uterus contracts to expel the placenta. This
is called afterbirth.

118. Parental Care involves
1. feeding the baby (lactation)
 mammary glands secrete milk
2. keeping baby clean
3. warm

119. Breast-feeding
 allows close contact between the mother
and her baby, which is good for both of
them, physically and emotionally

120. The mother’s milk is perfect food for
the baby because it contains:
1. all the necessary nutrients
2. the mother’s antibodies which makes the baby
immune from disease during the first few
months of life

121. A newborn baby cannot take in solid
food because:
 no teeth to chew
 the digestive system cannot deal with
solid food

122. Colostrum:
 is produced by the breasts beginning during
pregnancy and continuing through the early
days of breastfeeding

123. Colostrum:
 is yellow to orange in colour and thick and sticky
 is low in fat, and high in
carbohydrates, protein, and antibodies to help
keep the baby healthy
Colostrum Breast milk

124. Colostrum:
 is extremely easy to digest, and is therefore the
perfect first food for the baby
 has a mild laxative effect, helping the baby to egest
for the first time
 has white blood cells in it to protect baby from
viruses and bacteria

125. Pregnancy Test

126. Birth control or Contraception

127. Birth control or Contraception
 contraception is any procedure which
prevents fertilisation
 Three groups:
1. stop sperms reaching the egg
2. stop the eggs being produced
3. stop the fertilised egg from developing in
the uterus [not in syllabus]

128. Birth control methods can be:
 Natural e.g.
 temperature (thermal) method
 the mucus Billings method
 Artificial e.g.
 use of the:
 Condom
 Diaphragm
 Contraceptive pill

129. None of the contraceptive methods is
100% effective.

130. What is the MOST effective method
of avoiding pregnancy?

131. Temperature (Thermal) method
 the body temperature rises slightly at the
time of ovulation

132. Temperature (Thermal) method
 the body temperature is
taken every morning and a
graph is plotted

133. Digital fertility
thermometer

134. If pregnant:
 no menstruation
 the body temperature
remains up
throughout pregnancy
The temperature is low until ovulation, after which it rises
for 10-16 days, and drops back with onset of period.

135. Two Australian doctors: The mucus
Billings method
Dr Evelyn & Dr John Billings

136. The mucus Billings method
 helps to determine the time of ovulation

137. Why is mucus produced at the cervix?
 to protect the sperm from the acidity in the
vagina
 to allow sperm to move freely through the
cervix

138. Days with & without mucus during
the menstrual cycle
Pre-ovulation:
no mucus
Post-ovulation:
no mucus

139.  Pre-Ovulation
 Dry at first
 Gradually, more mucus will accumulate –
yellow, cloudy, or white in color and sticky to
the touch.
Texture of mucus changes

140.  Approaching Ovulation
 the cervical mucus will increase
 first, there will be a moistness or
stickiness to the mucus, as well as a white
or cream-colored appearance.

141.  During Ovulation
 mucus = large amount ; resembles “egg
whites”, often semitransparent.
 mucus = increasingly slippery and
‘stretchable’. This is the most fertile time.

142.  Following Ovulation
 Mucus = less slippery ; becomes sticky
and cloudier

143. Sperms cannot swim through
thick mucus
INFERTILE
FERTILE
Sperms can
swim through
thin mucus

144. Watery

145. Combined with
temperature:
On its own:
The mucus method

146. Question: MAY 2010
Compare the cervical mucus in the female
reproductive system at ovulation and after
ovulation. (2)
At ovulation, cervical mucus gets very wet,
stretches between the fingers for an inch or
more, and resembles raw egg white. After
ovulation, cervical mucus becomes sticky and
cloudier and dryness may also result.

147. The sheath (condom)
 is worn by the male over the erect penis
 forms a barrier to sperms

148. The sheath (condom)
 is quite reliable if used properly; best to use it
with a spermicide
 disadvantage:
 can tear
 slip off

150. The cap or diaphragm (fig. 17)
 is worn by the female just before sex
 a barrier to sperms
 disadvantage:
 can slip out of place

151. Question: SEP, 2010
Explain how the use of a diaphragm by a
female prevents fertilisation. (1)

152. Spermicides
kill sperms

153. Spermicides
 unreliable on their own, but
improve efficiency of the
diaphragm and sheath

154. The oral contraceptive pill:
 taken by the female to prevent any eggs
being produced in the ovary
 it stops ovulation
 one tablet is taken
daily throughout the
menstrual cycle except
for about a week
during menstruation

155. The oral contraceptive pill:
 contains chemical substances identical to
oestrogen and progesterone
 very effective
 Disadvantages:
1. can raise blood pressure
2. cause an increase in weight

156. Sterilisation:
 the person has an operation which prevents
conception permanently
Vasectomy:
Sterilisation of a man
 about 1 in 2,000 men
can become fertile
again after a
vasectomy

157. Tubal ligation:
Sterilisation of a woman
 more than 99% effective
 1 in 200 women will
become pregnant after
being sterilised

158.  there is a slightly higher risk of ectopic
pregnancy after tubal ligation

159. As a last note: ever
hear of viagra?

160. Question: MAY 2012
A young female had a contraceptive implant in
which tubes of progestin (a form of
progesterone) were implanted under the skin.
Name TWO hormones that are not released from
the pituitary gland as a consequence of this. (2)
FSH
LH

161. Question: MAY 2009
Describe each of the following processes and
explain the benefits of each:
vasectomy; (3)
Vasectomy is a form of relatively permanent
birth control method/contraception in males.
The sperm ducts are cut and tied in a surgical
operation to prevent sperms from being
ejaculated.

162. Question: MAY, 2010
1) Explain why a male still continues to have a
deep voice after he undergoes a vasectomy?
A deep voice is due to the effect of testosterone.
This sex hormone is still produced in the body.
2) Explain why after a vasectomy the seminal fluid
contains no sperm. (3)
As the sperm ducts are cut and tied and sperms
cannot move into the urethra.

163. THE
END