Name: ____________________
IGCSE Combined Science
Unit 4 Work Booklet
Transport, Coordination and Reproduction in
Humans
1
Specific Learning Objectives (SLO’s)

Objectives listed with E are Extension level objectives.
1 RESPIRATION
KNOWLEDGE AND UNDERSTANDING





Define respiration as the chemical reactions that break down nutrient molecules in
living cells to release energy.
State the uses or energy in the body of humans: muscle contraction, protein
2.
synthesis, cell division, growth, the passage of nerve impulses and the
maintenance of a constant body temperature.
State the word equation and the balanced symbol equation for aerobic
3.
respiration.
Define aerobic respiration as the release of a relatively large amount of energy in
4.
cells by the breakdown of food substances in the presence of oxygen.
5E. State the equation for aerobic respiration using symbols
(C6H12O6 + 6O2 → 6CO2 +6H2O).
1.
1b GAS EXCHANGE IN HUMANS:
KNOWLEDGE AND UNDERSTANDING
Identify on diagrams and name the parts of the human gas exchange system –
larynx, trachea, bronchi, bronchioles, alveoli, and associated capillaries.

1.

2E. List the features of gas exchange surfaces in animals.


3E. Explain the role of mucus and cilia in protecting the gas exchange system from
pathogens and particles.
4E. Describe the effects of tobacco smoke and its major toxic components (tar,
nicotine, carbon monoxide, smoke particles) on the gas exchange system.

5.
State the differences in composition between inspired and expired air.
PRACTICAL SKILLS

1.

2E. Investigate and explain the effects of physical activity on the rate and depth of
breathing.
Investigate the components in inspired and expired air using limewater.
2 TRANSPORT IN HUMANS:
KNOWLEDGE AND UNDERSTANDING

1.

2E.

3.

4E.
Describe the circulatory system as a system of tubes with a pump and valves to
ensure one-way flow of blood.
Describe the double circulation in terms of a low-pressure circulation to the lungs
and a high-pressure circulation to the body tissues and relate these differences
to the different functions of the two circuits.
Describe the structure of the heart including the muscular wall and septum, atria,
ventricles, valves and associated blood vessels.
Describe coronary heart disease in terms of the blockage of coronary arteries
and state the possible causes (diet, stress and smoking) and preventive
measures.
2
List the components of the blood and state their functions – red blood cells, white
blood cells, platelets and plasma.
the function of the heart in terms of muscular contraction and the
 6. Describe
working of the valves.
PRACTICAL SKILLS

5.

1E.
Investigate, state and explain the effect of physical activity on pulse rate.

2.
Identify red and white blood cells as seen under a microscope, and in diagrams
and photomicrographs.

3.
Dissect a heart.
3 HUMAN REPRODUCTION:
KNOWLEDGE AND UNDERSTANDING

1.

2.

3E.
Compare male and female gametes in terms of size, numbers and mobility.

4.
Describe the menstrual cycle in terms of changes in the uterus and ovaries.

5.

6.

7E.
Indicate the functions of the amniotic sac and amniotic fluid.

8E.
Describe the function of the placenta and umbilical cord.

9.

10.
Describe the methods of transmission of HIV and the ways in which HIV/AIDS
can be prevented from spreading

11E.
Outline how HIV affects the immune system.
Identify on diagrams the parts of the male reproductive systems and state the
functions of these parts.
Identify on diagrams the parts of the female reproductive systems and state
the functions of these parts.
Describe fertilisation in terms of the joining of the nuclei of the male gamete
(sperm) and female gamete (egg).
Outline the early development of the zygote in terms of the formation of a ball
of cells that becomes implanted in the wall of the uterus.
Describe the advantages and disadvantage of breast-feeding compared with
bottle-feeding using formula milk.
HIV and AIDS
3b COORDINATION IN HUMANS BY HORMONES:
KNOWLEDGE AND UNDERSTANDING

Define a hormone as a chemical substance, produced by a gland, carried by the
1. blood, which alters the activity of one or more specific target organs and is then
destroyed by the liver.
2. State the role of the hormone adrenaline in chemical control of metabolic activity,
including increasing the blood glucose concentration and pulse rate.

3. Give examples of situations in which adrenaline secretion increases.

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1 RESPIRATION
1. Respiration - the chemical ____________ that break down nutrient molecules in living cells to release
_______________.
2. Uses of energy in the body of humans:






contracting muscles, so that we can ____________ parts of the body
making ____________ molecules by linking together amino acids into long chains
__________ division, so that we can repair damaged tissues and can grow
active transport, so that we can __________ substances across cell membranes up their
concentration gradients
transmitting ____________ impulses, so that we can transfer information quickly from one
part of the body to another
producing ___________inside the body, to keep the body temperature constant even if
the environment is cold
3. a) Write the word equation for respiration
b) Write the balanced chemical equation for respiration
4. Aerobic respiration - the release of a relatively large amount of energy in cells by the breakdown of food
substances in the presence of ________________.
Applying your knowledge
1. Investigating heat production by germinating peas
a) Which thermos flask would show a higher temperature at the end of the experiment? Why?
b) Why are the seeds washed with a disinfectant before placing them in the flasks?
c) It is advisable not to fill the flasks completely with seeds. Why?
d) Why are the flasks supported in the upside-down position?
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2. The production of carbon dioxide by a respiring animal
a) Why is it necessary to bubble the incoming air through potassium hydroxide solution before it
is supplied to the mouse?
b) Which solution changes colour at the end of the experiment? What does this show?
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The lungs
 Use the letters by the parts to label the diagram of the lungs (highlighted labels are less important)
Plural membranes A.
Alveoli
B.
Larynx
C.
Plural fluid
D.
Heart
E.
Diaphragm
F.
Trachea
G.
Bronchiole
H.
Left bronchus
I.
Intercostal muscles J.
Left lung
K.
Air space
A.
Air entering/leaving
the alveoli
B.
Oxygen diffusing into
the blood
C.
CO2 diffusing out of
the blood
D.
Deoxygenate blood
E.
Oxygenated blood
F.
Red blood cell
G.
Blood capillary –
1 cell thick
H.
Wall of the alveoli – 1
cell thick
I.
The Alveoli and gas exchange
 Complete the diagram below using the labels in the table
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1. List the features of gas exchange surfaces in animals.
a) The walls of the alveoli are made from a single layer of cells. Why is the advantage of this?
b) The alveoli have a moist lining. Why is this useful?
c) The lungs contain a lot of alveoli. Why is this an advantage?
2. Explain the role of mucus and cilia in protecting the gas exchange system from pathogens and
particles.
 Highlight the key points in the following paragraphs:
The bronchi in the lungs are lined with something called cilia cells. They
are cells that line the lungs with hair-like protrusions. The cilia cells sweep
any unwanted microbes or particles out of our lungs and airways.
Scattered in between cilia cells are goblet cells that produce mucus. The
role of the mucus is to trap any unwanted particles, making the job of
cilia cells easier. The mucus is also protects the cilia cells by lining it with
a layer of mucus.
3. Describe the effects of tobacco smoke and its major toxic components (tar, nicotine, carbon
monoxide, smoke particles) on the gas exchange system.
Overall, tobacco and smoking can have a very negative effect on the gas exchange system. Identify the major
toxic components described below and highlight the key points.
___________________: This causes more mucus to be produced by the goblet cells. In addition, it also paralyses
our cilia cells, meaning that they cannot properly function and remove the mucus. The result is that excess
mucus builds up in our airways. Smokers cough more often to shift the mucus to the back of their throats. It also
clogs up the alveoli in our lungs, reducing the surface area for gas exchange to take place, therefore resulting in
less oxygen entering your body. It is also a carcinogen, a substance that increases the risk of cancer. When it is
deposited in our lungs it raises the risk of lung cancer amongst other diseases such as
chronic bronchitis.
___________________: The presence of this in our bloodstream raises our hearts’ beat per
minute, in addition to increases blood pressure by narrowing our blood vessels.
___________________: This binds with the haemoglobins in our red blood cells, reducing its ability to carry
oxygen around our body. As a result, it puts more strain our body’s respiratory system.
___________________: These may coat the walls of the alveoli, preventing gas exchange from taking place.
Research: Write a paragraph in your Notes about each of the following:
a) What is bronchitis?
b) Describe what emphysema is and how a smoker gets it.
c) How does lung cancer occur?
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4. State the differences in composition between inspired and expired air.
Exhaled air has high levels of ______________________ and ________________________ while inhaled air has
O2 and very little amount or no water vapour.
Inspired air has around 21% of ________________ whilst expired air consists of 17% oxygen.
5. Describe and explain the effects of physical activity on the rate and depth of breathing
The physically and mentally relaxed human breathing rate is about 16 breaths a minute. Each inhalation brings in
about half of litre of air. A similar volume of air is exhaled.
Physical exercise greatly increases the breathing rate. The rate may increase beyond 80 breaths per minute. It
also increases the depth of breathing increasing from half a litre to four litres.
 Why is this increase in breathing rate needed?
Applying your knowledge
a) What solution is in the test tubes?
b) What happens to this solution when carbon dioxide
passes through it?
c) Which side of the apparatus produces bubbles when
air is:
I.
Inhaled/inspired through the mouthpiece?
II.
Exhaled/expired through the mouthpiece?
d) Add arrows to show the direction of air flowing through the apparatus.
e) Will the solution in tube A or tube B change first?
f)
Which contains the most carbon dioxide expired or inspired air? Explain the answer
2 TRANSPORT IN HUMANS:
1. Describe the circulatory system as a system of tubes with a pump and valves to ensure one-way flow of
blood.
The circulatory system is the system in which blood is pumped around the body. We need this system to
transport o____________ and n____________ to our body cells for respiration.
V____________ are devices that control the direction of the
flow of blood. They achieve this by closing and opening to
prevent blood from flowing both ways.
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2. Describe the double circulation in terms of a low pressure circulation to the lungs and a high
pressure circulation to the body tissues and relate these differences to the different funtions of the
two circuits.
The body contains a “double circulatory system”, where one circuit pumps blood to the
______________, where _____________ is acquired and _______________________ is released.
The oxygenated blood then enters the second circuit, which takes oxygen to the ___________.
 Explain why when blood is transported from the heart to the lungs, the pressure it travels at
is relatively smaller than the second circuit, where the blood is transported from the heart to the rest of
the body.
3. Describe the structure and function of the heart.
The heart has four chambers, two atria and two ventricles.
The sides of the heart are separated by the septum. Each side of the heart contains an atrium and a ventricle,
atrium at the top, ventricle on the bottom, and there is a valve between the atrium and ventricle of each side.
On the left, the valve is called the bicuspid valve, and on the right, the tricuspid valve.
There are four major blood vessels associated with the heart:
 Pulmonary Veins: This transports __________________ blood from the lungs to the left atrium
 Aorta: This transports oxygenated blood from the __________ to the rest of the body and the brain.
 Vena Cava: This transports deoxygenated blood from the rest of the body to the ____________.
 Pulmonary Artery: Transports deoxygenated blood from the heart to the ____________.
 Label the diagram below
A.
Tricuspid valve
B.
Bicuspid valve
C.
Semi-lunar valves
D.
Septum
E.
Right ventricle
F.
Left ventricle
G.
Right atria
H.
Left atria
I.
Pulmonary vein
J.
Pulmonary artery
K.
Aorta
L.
Vena cava
M.
Tendons
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The 4 chambers of the heart
Complete the table below to describe the four chambers of the heart and the flow of blood around the
heart
Part of the
heart
Gets blood from…
Left
atria
Pulmonary vein from
the lungs
Blood is oxygenated or
deoxygenated?
Thick or thin
walls?
Blood pumped
to….
Left
ventricle
Right atria
Right
ventricle
The Circulatory system
Colour the right side red (oxygenated blood) and
the left blue (deoxygenated blood)
Add arrows to show the direction of flow.
Use the letters and arrows below to label the
diagram
A. Aorta – from heart to ________
B.
Body capillaries in tissues –
_________ exchanged for CO2
C. ____ ____ - from body to heart
D. Pulmonary artery to the ______
E.
Lung capillaries – CO2
_____________ for oxygen
F.
Pulmonary _______ - from the
lungs to heart
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4. Describe coronary heart disease in terms of the blockage of coronary arteries and state the possible
causes (diet, stress and smoking) and preventive measures.
Coronary Heart Disease is a heart disease where certain parts of the
“coronary artery” becomes “clogged” with cholesterol, and substances such
as oxygen and nutrients cannot be transported across the body.
If not properly treated, a blood clot may form near the partially “clogged”
area, completely blocking the artery. The muscle cells in the heart need a
constant supply of oxygen and nutrients and if the coronary arteries that
supply blood to the heart muscles become blocked a heart attack can happen and part of the heart dies.
Heart attacks: Put the following statements in order by numbering them 1-5.
_______
These cells start to die.
_______
A blood clot can form on a fatty deposit.
_______
Some heart muscle cells do not get the oxygen and nutrients they need.
_______
The blood clot can block a coronary artery.
_______
Fatty deposits build up in the coronary arteries.
 RESEARCH TASK: List 5 possible causes of Coronary Heart Disease
5. List the components of the blood and state their functions – red blood cells, white blood cells, platelets
and plasma.
• ______________________________– haemoglobin and oxygen transport.
• ______________________________ – phagocytosis and antibody formation,
• ______________________________ – causing clotting,
• ______________________________ – transport of blood cells, ions, soluble nutrients, hormones and
carbon dioxide.
6. Identify red and white blood cells as seen under a microscope, and in diagrams and photomicrographs.
Red Blood Cells



R________ in color
Biconcave Disk Shape
No n_____________
White Blood Cells



B__________ than Red Blood Cells
Exist in fewer amounts than Red Blood Cells
Have a n____________
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7. Investigate, state and explain the effect of physical activity on pulse rate.
 Highlight the key points in the paragraph below.
With exercise or physical activity, the heart rate increases to supply the muscles with more oxygen to gain extra
energy. The heart can beat up to 200 times per minute with extreme exercise. The brain sends nerve signals to
the heart to control the rate. The body also produces chemical hormones, such as adrenaline, which can change
the heart rate. When we are excited, scared, or anxious our heart gets a signal to beat faster. During a fever, the
heart beats faster to bring more blood to the surface of the body to release heat and cool the body. The heart
rate increases during and after a meal to send more blood to the digestive system. A trained athlete’s heart can
pump more blood with each beat so his or her heart rate is slower. Likewise, an athlete’s recovery time is
shorter.
3 HUMAN REPRODUCTION:
1. Identify on diagrams the parts of the male and female reproductive systems and state the
functions of these parts.
 ______________- Produces sperm and male sex
hormone, testosterone
 ______________- sack of skin which holds the testis
 ______________- carries sperm from testes to urethra
 ______________- produces alkaline fluid to add to
sperm to make semen.
 ______________-carries semen to the penis.
 ______________- transfers sperm into vagina





______________- This is where the eggs are stored and
hormone is produced.
______________- This is where fertilization happens. The egg
travels along the oviduct during ovulation, which happens
after a woman has her menstruation.
______________- lower part of the uterus
______________- sperm is deposited in the vagina during
sexual intercourse
______________- is able to expand and holds the embryo/
baby
2. Describe the menstrual cycle in terms of changes in the uterus and ovaries.
Read the information below, highlight the key points and then answer
the questions.
There are four stages in the menstrual cycle.
Stage 1. Days 1-4. Menstruation (bleeding) occurs. The lining of the
uterus disintegrates and is shed. This is due to low levels of
progesterone.
Stage 2. Days 4-14. The uterine lining grows back. This is due to high
levels of oestrogen.
Stage 3. Day 14. The egg (called an ovum) is released. This is due to LH.
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Stage 4. Days 14-28. The lining of the uterus is maintained in case the egg becomes fertilised and implanted in the
uterus. Maintenance of the lining is due to high levels of progesterone.
a)
Which hormone causes the egg to be released?
b) Why is the lining of the uterus maintained after the egg is released?
3. Compare male and female gametes in terms of size, numbers and mobility.
 Place the following words in the appropriate part of the table below: millions,
stationary, small, usually one, big, very fast
Gamete
Size
Numbers
Mobility
Male
Female
4. Describe fertilisation in terms of the joining of the nuclei of the male gamete (sperm) and
female gamete (egg).
Fertilisation happens when a male gamete (__________) penetrates the wall of the __________ gamete (egg).
5. Outline the early development of the zygote in terms of the formation of a ball of cells that
becomes implanted in the wall of the uterus.
A single sperm cell penetrates the mother’s egg cell, and
the resulting cell is commonly called a ___________. A
zygote contains all the genetic information necessary for
one to become a child. Half of the genetic information
comes from the mother’s ________ and the other half
from the father’s _________. The zygote then spends the
next few days travelling down
the _________________________ and then divides to
form a ball of cells.
The zygote then continues to ______________, creating an
inner group of cells with an outer shell. This stage is
called blastocyst. The blastocyst arrives at the womb (uterus)
around day 5, and _____________ into the uterine wall on
about day 6. At this point in the mother’s menstrual cycle, the
lining
of
the
______________has grown and is prepared to support the baby.
6. Indicate the functions of the amniotic sac and amniotic fluid.
The amniotic sac and amniotic fluid ________________ the embryo inside the
womb from shocks of movement. It also protects the embryo/baby from
t_________________ changes of mother.
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7. Describe the function of the placenta and umbilical
cord.


The umbilical cord would carry dissolved food and
________________ to the body as well as carry urea
and ______________________ away from the foetus.
The placenta ensures the exchange between carbon
dioxide and oxygen in the baby’s bloodstream. This
ensures that ________________ can be moved into
the bloodstream and _________________________
taken away. However, the placenta also ensures that
other _________________ are allowed to pass to the
baby and other _____________ are removed.
8. Describe the advantages and disadvantage of breast-feeding compared with bottle-feeding
using formula milk.
Type of milk
Advantages
Disadvantages
Breast
Formula
9. Research task - On paper, record information about the following:
a) Describe the methods of transmission of HIV.
b) Describe the ways in which HIV/AIDS can be prevented from spreading.
c) Outline how HIV affects the immune system.
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3b COORDINATION IN HUMANS BY HORMONES:
1. Define a hormone as a chemical substance, produced by a gland, carried
by the blood, which alters the activity of one or more specific target organs
and is then destroyed by the liver.
 Learn the above definition
2. State the role of the hormone adrenaline in chemical control of metabolic
activity, including increasing the blood glucose concentration and pulse
rate.
There are two adrenal glands, one above each kidney. They make a
hormone called adrenaline. When you are frightened or excited, your brain
sends impulses along a nerve to your adrenal glands. This makes them
secrete adrenaline into the blood.
Adrenaline has several effects which are designed to help you to cope with
danger. For example, it makes your heart beat faster, supplying oxygen to
your brain and muscles more quickly. This gives them more energy for
fighting or running away.
The blood vessels in your skin and digestive system contract so that they carry very little blood. This makes you
go pale, and gives you ‘butterflies in your stomach’. As much blood as possible is need for your brain and
muscles in the emergency.
Adrenaline also causes the liver to release glucose into the blood.
This provides extra glucose for the muscles, so that they can
release energy from it (by respiration) and us the energy for
contracting.
 Write down two things you already knew about adrenaline
before reading the paragraphs above.
 Write down two things you learnt about adrenaline by reading the paragraphs above.
 Highlight the key information in the paragraphs.
 Give two examples of situations in which adrenaline secretion increases.
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