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Biology Term 1
B1.7
Unit 1 – Cells
B1.1
Unit 2 – Size matters
B2.1
Each side is a square so:
B1.1 TB
The largest known living single-celled organisms
are sponge-like creatures called xenophyophores
that live on the ocean floor. They can reach a size
of up to 20 cm across.
Surface area of each square = 4 cm  4 cm
= 16 cm2
Total surface area of cube = 16  6 = 96 cm2
Volume of cube = 4 cm  4 cm  4 cm = 64 cm3
The biggest egg ever laid was about 30 cm in
length and was laid by an animal that is now
extinct: the Elephant Bird of Madagascar.
So the surface area to volume ratio = 96/64 = 1.5
B1.3
B2.2
Eyepiece
Objective
Magnification
A mouse has fur over its body and face to keep
heat in. It also sits very close to the ground and
can roll up into a ball to keep heat in.
10
10
100
B2.3
15
100
1500
5
20
100
10
40
400
Large organisms need much more energy to live
than small organisms, so they have larger and
more complicated digestive systems. They need
big, powerful hearts to pump the blood around
their circulatory systems.
B1.5
B2.3 TB
Specialised human cells include red blood cells,
white blood cells, muscle cells, brain cells, sex
cells (gametes), liver cells, skin cells.
A small bird such as a hummingbird has feathers
to keep warm and to help it fly. It flies short
distances and has to flap its wings very fast. Its
heart is small and beats very fast to keep
circulating its blood. It spends most of the daytime
finding food, and eats higher energy food such as
nectar. Many small birds huddle together in groups
at night to share warmth.
In a flowering plant, specialised cells include root
hair cells, leaf cells, gametes (sex cells) and
palisade cells.
B1.6
Excretory system: liver, kidneys
Nervous system: brain
Digestive system: stomach, intestines
A small mammal such as a bat lives and sleeps
during the day huddled together with many other
bats to keep warm. It lives in warmer,
sheltered, dark places out of reach of
predators. Its wings are made of skin that it
wan wrap around itself to keep warm; its
body is covered in fur. It spends most of
the night flying fast and catching and
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SMART SCIENCE
1
Biology Term 1 – Answers to Student’s Book questions
Answers: Student’s Book questions
Biology Term 1 – Answers to Student’s Book questions
Answers: Student’s Book questions
eating insects. Bats hibernate over the winter to
avoid cold temperatures and lack of food.
Unit 9 – Movement
A small reptile such as a lizard seeks out warm,
sunny places in which to spend the day. Lizards
are cold-blooded, meaning they need external
warmth such as from the Sun in order to live.
When they need to move they do so quickly, in
order to catch prey such as insects.
B9.1
B2.4 TB (1)
B9.2
Total volume of lungs is about 6000 cm3. There
are 10 mm in every 1 cm, so there are 1000 mm3
in every 1 cm3. So the total volume of lungs is
about 6000  1000 = 6000 000 mm3
Bones have blood vessels because the living cells
in bone need a supply of nutrients. Also, the new
blood cells formed in the bone marrow need to be
carried away to join the rest of the blood in the
body.
A sensitive plant detects an object nearby by a
change in the electrical charge on the leaves. The
leaves then fold up, and the leaf stalks droop
down, because the plant withdraws water from the
leaves and stalk.
B2.4 TB (2)
Number of alveoli 

volume of lungs
volume of one alveolus
6000 000
 750 million
0.008
B2.4 TB (3)
Total surface area = area of one alveolus 
number of alveoli = 0.2 mm2  750 000 000
= 150 000 000 mm2 = 1500 000 cm2
B2.4 TB (4)
Total surface area of lungs if they were simple
spheres = 2000 cm3. So by having millions of
alveoli inside the lungs, the total surface area =
1500 000
= 750 times larger than simple spheres.
2000
B2.4 TB (5)
Surface area of tennis court = 23.2  8.2 = just
over 190 m2 = 1900 000 cm2. So the surface area
of the alveoli in our lungs is not much smaller than
the area of a tennis court!
B2.5
A blue whale’s brain is the largest brain known. It
has a mass of about 6.0 kg, which is slightly more
than four times more massive than a human brain.
This might mean blue whales are very intelligent,
but we know that the size of an animal’s brain
does not necessarily relate to the animal’s
intelligence. (We know that whales communicate
through complex sounds and show intelligent
behaviour, but we cannot tell how intelligent they
may be from the size of their brains.)
2
TEACHER’S HANDBOOK 1
B9.5
The thigh contains an antagonistic pair of muscles,
one in the front and one behind the bone. (There
are more muscles than this in the thigh, but this
explains the basic principle.) To lift the leg up, the
front muscle contracts while the back muscle
relaxes; to push the leg back down, the front
muscle relaxes and the back muscle contracts.
B9.5 TB
What appears to be a ‘knee’ on a flamingo is in
fact the equivalent of a human ankle. The
flamingo’s knee is hidden under its feathers, higher
up near the top of its leg.
B9.6 (1)
Bones help protect your organs from damage, as
well as hold the parts of our body in place and
make blood. If you are playing sports, you can
protect your bones from damage by wearing
protective clothing and being careful. If you are
unlucky enough to break a bone, if it did not repair
itself you would lose protection of your organs in
that part of your body, and you might not be able
to walk (if, for example, a leg bone stays broken).
B9.6 (2)
Fruit and vegetables provide minerals and
vitamins. We can get minerals and some vitamins
from dairy products too such as milk.
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