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Further Biology Revision Notes

Further Biology B3
Transporting Substances

There are two main ways substances are moved into and out of cells:

Diffusion ­ the net movement of particles along a concentration gradient;
Osmosis ­ the movement of water along a concentration gradient, involving a partially
permeable membrane.

However, sometimes…

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Further Biology Revision Notes

Exchange in the gut

The molecules from food need to be made available to your body cells; to provide fuel for
respiration and the building blocks for all the tissues of your body. Subsequently, they have to move
from the inside of the small intestine to…

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Further Biology Revision Notes


When the stomata on the leaves of plants open to allow carbon dioxide to come in, some water
vapour is lost. This loss of water vapour is known as transpiration.

As water evaporates from the surface of the leaves, water is pulled up through the…

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Further Biology Revision Notes

Because of the double circulation, the heart has two pumps, which beat together about 70 times
each minute. The walls of the heart are almost entirely muscle, supplied with oxygen by the coronary
blood vessel.

Transport in the blood

Blood is a complex mixture of cells…

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Further Biology Revision Notes

Muscle fibres need energy to contract. They contain many mitochondria to supply the energy they
need by aerobic respiration. Muscles contain glycogen stores, which can be rapidly converted to
glucose to supply the fuel needed for cellular respiration when your muscles contract.

Cellular respiration:

Glucose +…

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Further Biology Revision Notes

If you have been exercising hard, your heart rate and breathing rate remain high for a period of time
(the length of time depends on how fit you are).

Waste lactic acid from anaerobic respiration cannot be removed just by breathing as with carbon
dioxide. The…

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Further Biology Revision Notes

fluid contains no urea so there is a strong concentration gradient from the blood to the fluid, and all
the urea leaves the blood.

Disadvantages of using a dialysis machine: has to be used at regular intervals; sessions are long;
patients must follow a carefully controlled…

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Further Biology Revision Notes

The nutrients are often contained in an agar medium (agar is a substance which dissolves in hot water
and sets to form a jelly). Your pour hot agar containing the nutrients into a petri dish, leave it to cool
and then add the microorganisms.

The other…

Page 9

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Further Biology Revision Notes

Producing microbes on a much larger scale can bring with it many problems:

The metabolism of all the millions of microorganisms cause the temperature to rise
The carbon dioxide waste from respiration can alter the pH of the culture (changes in pH can
affect the activity…


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