1. BIOLOGY FORM 5
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2. SUBTOPICS
• The Importance of Having a Transport System in
Some Multicellular Organisms
• The Circulatory System
• The Mechanism of Blood Clotting
• The Lymphatic System
• The Role of the Circulatory System in the Body’s
Defence Mechanism
• Appreciating a Healthy Cardiovascular System
• The Transport of Substances in Plants
• The Transport of Organic Substances & Water in
Plants 2

3. 3

4. 1.1 - The Importance of Having
a Transport System in Some
Multicellular Organisms
• LEARNING OUTCOMES :
• To identify the problem that could be
faced by multicellular organisms in
obtaining their cellular requirements
& getting rid of their waste products
• To suggest how the problem is
overcome in multicellular organisms
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5. 1.1 - The Importance of Having a
Transport System in Some Multicellular
Organisms
• All living organisms need
to constantly exchange
substances between cells
& their external
environment (food, waste
& gases).
• All this process is
performed by a transport
system. 5

6. • Small organisms have a large total surface area
to volume (TSA/V) ratio. So, diffusion of
substances occurs rapidly (short distance only).
• Some simple organisms such as flatworms have thin
flatten bodies  provide a large surface area
• In Hydra, water enters through the mouth into the
body cavity. As the body wall is only two cell layers
thick, substances can move rapidly into or out of
the body cells.
• Do not require a specialised internal transport
system 6

7. • Larger organisms, increased need for
more nutrients & oxygen to be supplied to
the larger number of cells. Need to
excrete more waste products.
• The size increases, TSA/V ratio
decreases.
• Many of the body cells are too far away
from the external surface or between
different parts of the body.
• Simple diffusion occurs at too slow a rate
to sustain cellular activities.
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8. • Larger multicellular organisms have
adapted by developing specialised
structures to increase the surface area for
exchange of substances.
• Have developed an internal transport
system of vessels or tubes.
• In human & more complex animals, there
is development of a blood circulation
system to carry the substances.
• In plants, transport of substances is carried
out by the vascular system (xylem &
phloem).
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9. EXPERIMENT 1.1 : Determining
the relationship between total surface
area to volume ratio & its effect on the
rate of diffusion
• AIM : To determine the relationship between
TSA/V ratio & its effect on the rate of diffusion
• PROBLEM STATEMENT : What is the effect of
TSA/V ratio on the rate of diffusion of
substances?
• HYPOTHESIS : the larger the size of the
object, the smaller the total surface area to
volume ratio & the lower the rate of diffusion
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10. • VARIABLES : Manipulated – size of potato cubes,
Responding – Area stained relative to total
surface area of cut surface, Fixed – red ink
solution, potato
• MATERIAL : potatoes, coloured solution
• APPARATUS : 400 ml beaker, white tile, knife,
ruler & forcep.
• PROCEDURE :
– A knife is used to cut 3 potato cubes with the
dimensions 1cm x 1cm x 1cm, 2cm x 2cm x 2cm, 4cm
x 4cm x4cm
– The 3 potato cubes are immersed in coloured solution
for 30 minutes
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11. • PROCEDURE (cont…)
– The potato cubes are removed from the
beaker. Each potato is cut in half. The region
stained by the colour solution are observed.
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12. •RESULT :
A B C
Original length (cm) 1 2 4
Original width (cm) 1 2 4
Original height (cm) 1 2 4
Total surface area
(cm2)
Volume (cm3)
TSA/V ratio
Relative rate of diffusion
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13. • DISCUSSION :
– Answer the questions inside the practical book
page 3
• CONCLUSION :
– Make your own conclusion
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14. END
OF
SUBTOPIC 1.1
OPPS…DON’T FORGET TO COPY
EXERCISE ON THE NEXT PAGE!!
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15. EXERCISE 1.1
• State two problems faced by multicellular
organisms in obtaining their cellular
requirements & removing waste product.
3. State how these problems are overcome
in multicellular organisms.
3. Explain why unicellular organisms do not
face the problems listed in (Q1).
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16. Iyah..iyah.
.Iyah….
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