B4 Human Reproduction

Question 1

Approximately how often is an egg released from the ovaries of a mature female (ovulation)?

Answer 1

Every month (or 28 days)

Question 2

Fertilisation normally takes place in the…

Answer 2

Oviduct

The oviduct is the tube which connects the ovary to the uterus.

Question 3

A newly fertilised egg is sometimes called a…

Answer 3

Zygote

It’s the last word in the dictionary but the first cell!

Question 4

The structure that provides the fetus with food and oxygen is called the…

Answer 4

Placenta

Question 5

The Fetus’ blood travels from the fetus to the placenta through the…

Answer 5

Umbilical cord

Question 6

Explain how the growing fetus obtains food and oxygen. Use the following words: fetus’ blood, mother’s blood, placenta, umbilical cord, oxygen, glucose, diffuses.

Answer 6

Glucose and oxygen from the mother’s blood diffuses through the placenta into the fetus’ blood.
The fetus’ blood travels down the umbilical cord to the fetus.

Question 7

The transfer of oxygen from the mother’s blood to the fetus’ blood in the placenta is called…

Answer 7

Diffusion

This is when soluble substances pass through thin menbranes.

Question 8

The growing fetus is protected from physical shocks by the…

Answer 8

Amniotic fluid

The amniotic fluid is contained within the amniotic sac.

Question 9

Things which pass from the mother to the fetus across the placenta include…

Answer 9

Oxygen

Carbon dioxide goes the other direction. The other two are insoluble, so can’t travel accross the placenta.

Question 10

In humans, the time from fertilisation to birth is normally about…

Answer 10

9 months

Question 11

What is the male gamete and where are they produced?

Answer 11

Sperm cells.
They are made by the testes.

Question 12

In humans how do the gametes differ in size and number produced?

Answer 12

Sperm cells are very tiny and produced in large quantities.
Egg cells are large and only one is released each month.

Question 13

What is the female gamete and from where are they released?

Answer 13

Egg Cell.
Released by the ovary each month.

Question 14

Describe what happens during human fertilisation. Use these words: sperm cell, egg cell, zygote.

Answer 14

The sperm cell reaches the egg cell in the oviduct.
The nucleus of each cell joins forming a new cell called a zygote.

Question 15

Explain what happens to the egg immediately after fertilisation.

Answer 15

The fertilised egg (called a zygote) continues down the oviduct to the uterus where it will hopefully implant in the soft lining.

Question 16

Explain why a male and a female are required for sexual reproduction. Use these words in your answer: gamete, gene.

Answer 16

The male and female both contribute gene, contained in the gametes.

Gametes (sperm cells and egg cells) are special because they only have half the genes. Both gametes must combine to make a new individual.

Question 17

In humans, how do sperm cells and egg cells differ?

Answer 17

Sperm cells are tiny and produced in millions throughout a man’s life.
Egg cells are large and one is released by women each month (until they reach the menopause).

Question 18

Explain how the growing fetus obtains food and oxygen from its mother.

Answer 18

Soluble food and oxygen from the mother’s blood diffuses through the placenta into the fetus’ blood.
The fetus’ blood travels down the umbilical cord to the fetus.

Question 19

Name the glands that produce milk following childbirth.

Answer 19

Mammary glands (in the breasts)

Question 20

Suggest two precautions a pregnant woman should take.

Answer 20

She should not smoke, drink or take drugs.
She must be careful about certain foods and medicines.
She must not overdo physical activity.

Question 21

Explain how the growing fetus gets rid of carbon dioxide. Use the following words: fetus’ blood, mother’s blood, placenta, umbilical cord, diffuses.

Answer 21

The fetus’ blood travels down the umbilical cord to the placenta.
Carbon dioxide from the Fetus’ blood diffuses through the placenta into the Mother’s blood.

Question 22

Suggest two functions of the testes.

Answer 22

Make sperm cells.
Release the male sex hormone (testosterone).

Question 23

Give two reasons why it is important that the blood of the fetus should not mix with the blood of the mother during pregnancy.

Answer 23

The mother’s blood will be under higher pressure which could damage the fetus.
They may have different blood groups which could lead to clotting.

Question 24

Explain why sexual reproduction cannot be successful until after both parents have reached puberty.

Answer 24

The gametes (egg cell and sperm cells) are not produced until puberty.

Question 25

How does asexual reproduction differ from sexual reproduction?

Answer 25

In sexual reproduction the genes from two individuals are combined.
In asexual reproduction the offspring is a genetic clone of one individual.

Question 26

What is a function of the testes?

Answer 26

Make sperm cells.
Release the male sex hormone (testosterone).

Question 27

What is a function of the ovaries?

Answer 27

Release egg cells.
Release the female sex hormones.

Question 28

Describe what happens during fertilisation in humans.

Answer 28

The sperm cell reaches the egg cell in the oviduct.
The nucleus of each cell joins forming a new cell called a zygote.

Question 29

Explain how carbon dioxide gets from a growing fetus to the atmosphere.

Answer 29

The fetus’ blood travels down the umbilical cord to the placenta.
Carbon dioxide from the Fetus’ blood diffuses through the placenta into the Mother’s blood.

Question 30

After fertilisation the embryo implants in the wall of the…

Answer 30

Uterus

Question 31

Which of these organisms can reproduce asexually? Snail, human, yeast or squid?

Answer 31

Yeast

New yeast cells (with the same genes) bud off from a single yeast cell.

Question 32

Carbon dioxide passes from a fetus to the mother across the…

Answer 32

Placenta