Sexual Reproduction, Development and Growth in Humans and Animals: Biology Tingkatan 4 questions

Section A: objective questions

12 marks

Choose the best answer for each question.

Which structure secretes mucus to help sperm swim to the Fallopian tubes?

Uterus
Cervix
Ovary
Vagina

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The cervix secretes mucus (p. 286).

For the teacher: Remembering, low difficulty, standard 15.1.1

Textbook p. 286

Which part of the male system produces testosterone?

Prostate gland
Seminal vesicle
Testis
Scrotum

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The testis makes sperm and testosterone.

For the teacher: Remembering, low difficulty, standard 15.1.1

Textbook p. 287

Why is the midpiece of a sperm packed with mitochondria?

To release energy for swimming
To store the nucleus
To digest the secondary oocyte membrane
To produce testosterone

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Mitochondria release energy for swimming to the Fallopian tube.

For the teacher: Understanding, low difficulty, standard 15.2.3

Textbook p. 292

How many functional gametes result from one oogonium after meiosis?

Four
Three
Two
One

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One secondary oocyte and polar bodies that die.

For the teacher: Understanding, low difficulty, standard 15.2.4

Textbook p. 292

At what stage is meiosis II of the secondary oocyte completed?

At ovulation
At puberty
When a sperm penetrates it
When the follicle forms

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Meiosis II is completed only after a sperm penetrates the secondary oocyte.

For the teacher: Remembering, low difficulty, standard 15.2.2

Textbook p. 291

Diagram 1 shows hormone levels in a 28-day menstrual cycle. Which hormone peaks on day 13 and causes ovulation?

Hormone level graph over 28 days — Diagram 1

Oestrogen
Progesterone
FSH
LH

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The LH peak on day 13 triggers ovulation on day 14.

For the teacher: Understanding, medium difficulty, standard 15.3.1

Textbook p. 295

Which hormone is mainly responsible for thickening the endometrium during days 15 to 21?

Progesterone
FSH
LH
GnRH

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Corpus luteum progesterone thickens the endometrium.

For the teacher: Applying, medium difficulty, standard 15.3.1

Textbook p. 295

What is the role of HCG in early pregnancy?

Causes ovulation
Makes the uterus contract
Keeps the corpus luteum secreting oestrogen and progesterone
Prevents the sperm from entering the oocyte

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HCG maintains the corpus luteum until the placenta takes over.

For the teacher: Understanding, low difficulty, standard 15.4.3

Textbook p. 298

Which blood vessel carries oxygen-rich blood to the foetus?

Umbilical vein
Umbilical artery
Aorta
Pulmonary vein

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The umbilical vein carries oxygenated blood from placenta to foetus.

For the teacher: Remembering, low difficulty, standard 15.4.4

Textbook p. 298

Which is a reason why maternal and foetal blood must not mix?

The foetus needs no oxygen
To prevent agglutination if blood groups differ
To allow antibodies to be removed
To let glucose pass easily

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Mixed blood of different groups may agglutinate.

For the teacher: Analysing, medium difficulty, standard 15.4.5

Textbook p. 299

A grasshopper has a life cycle of egg, nymph and adult. This is

complete metamorphosis
senescence
sigmoid growth
incomplete metamorphosis

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No pupa stage means incomplete metamorphosis.

For the teacher: Applying, low difficulty, standard 15.7.3

Textbook p. 304

In which phase of the sigmoid growth curve is the growth rate highest?

Lag phase
Exponential phase
Stationary phase
Maturity phase

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Cell division and elongation are most active in the exponential phase.

For the teacher: Understanding, low difficulty, standard 15.7.4

Textbook p. 305

Section B: structured questions

26 marks

Answer all questions.

Compare spermatogenesis and oogenesis.

[2 marks] (a)State where each process takes place.

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Spermatogenesis: seminiferous tubules of the testes [1]1
Oogenesis: ovaries [1]1

Tick each point you got.

[2 marks] (b)State two differences in the number and fate of the gametes produced from one germ cell.

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Spermatogenesis gives four sperms; oogenesis gives one secondary oocyte [1]1
Polar bodies of oogenesis die; all four sperms are functional [1]1

Tick each point you got.

For the teacher: Understanding, low difficulty, standard 15.2.4

Textbook p. 292

Diagram 2 shows hormone levels in a 28-day menstrual cycle. Use it to answer.

[1 mark] (a)Name the hormone with its peak at about day 22.

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Progesterone1

Tick each point you got.

[3 marks] (b)Explain what happens to the endometrium towards day 28 if there is no fertilisation.

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Corpus luteum degenerates [1]1
Progesterone and oestrogen fall [1]1
Endometrium sheds, menstruation [1]1

Tick each point you got.

[2 marks] (c)Explain why high progesterone prevents ovulation in pregnancy.

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Progesterone inhibits release of FSH and LH [1]1
No follicle growth or ovulation [1]1

Tick each point you got.

For the teacher: Analysing, medium difficulty, standard 15.3.1

Textbook p. 295

Diagram 3 shows early embryo development.

Embryo development until implantation — Diagram 3

[2 marks] (a)Arrange in order: blastocyst, zygote, morula, two-cell embryo.

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Zygote [1]1
two-cell embryo, morula, blastocyst [1]1

Tick each point you got.

[1 mark] (b)Name the process in which the blastocyst attaches to the endometrium.

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Implantation1

Tick each point you got.

[1 mark] (c)Which type of cell division produces the cells of the embryo?

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Mitosis1

Tick each point you got.

For the teacher: Understanding, low difficulty, standard 15.4.2

Textbook p. 297

Twins can be identical or fraternal.

[2 marks] (a)How are identical twins formed?

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One ovum fertilised by one sperm forms one zygote [1]1
The embryo divides into two [1]1

Tick each point you got.

[1 mark] (b)Why can fraternal twins be a boy and a girl?

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They come from two different zygotes with different genes1

Tick each point you got.

[1 mark] (c)How are conjoined twins formed?

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Incomplete division of the embryo of identical twins1

Tick each point you got.

For the teacher: Applying, low difficulty, standard 15.5.2

Textbook p. 301

A pregnant mother smokes.

[2 marks] (a)Explain why the foetus is still harmed although its blood does not mix with its mother's.

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Harmful substances such as nicotine cross the thin membrane of the placenta [1]1
They enter the foetal blood and disrupt development [1]1

Tick each point you got.

[2 marks] (b)State two substances moved from the foetus to the mother across the placenta.

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Carbon dioxide [1]1
Urea [1]1

Tick each point you got.

For the teacher: Evaluating, high difficulty, standard 15.4.5

Textbook p. 299

A grasshopper grows by ecdysis.

[1 mark] (a)What is ecdysis?

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Moulting of the exoskeleton1

Tick each point you got.

[2 marks] (b)Explain why the growth of an insect is intermittent.

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The hard exoskeleton cannot expand [1]1
Size increases only after ecdysis before the new exoskeleton hardens [1]1

Tick each point you got.

[1 mark] (c)Give one disadvantage of using dry mass to measure growth in animals.

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The organism must be killed1

Tick each point you got.

For the teacher: Understanding, medium difficulty, standard 15.7.5

Textbook p. 306

Section A: objective questions

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Section B: structured questions

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18