Page 38 - Biology Form Two

Biology for Secondary Schools

3. Shake the mixture. source. Place your burner on
4. Drop-wise, add 1% copper (II) the bench, never hold it in your
sulphate solution to the mixture hands. Use test tube holder to
while shaking. hold the test tube
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5. Record your observations. 5. Observe and record your findings.
6. Tabulate your results showing the
food sample tested, procedures, Questions

observation and inference 1. What did you observe when the
egg white was mixed with cold
Food
sample Procedures Observation Inference water?
tested
2. Were there any changes after
heating the mixture?

Question
What colour change did you observe? Chapter summary
1. Heterotrophic organisms are
incapable of making their
Activity 1.9: Investigate the solubility own food. Hence, they feed on
of protein in water and effects of heat different kinds of food made by
on proteins other organisms. Examples of

heterotrophs include all animals,
Materials
Egg white, water, test tubes, measuring fungi, some bacteria, and
cylinder (10 ml), test tube holder, and protoctists.
heat source 2. There are various types of
heterotrophic nutrition including
Procedure holozoic, saprophytic, and
1. Pour 3 ml of water into a test tube symbiotic nutrition or symbiosis.
followed by 2 ml of egg white. Symbiosis can be in the form
2. Shake the mixture. of commensalism (a kind of
3. Record your observations. relationship where one organism
4. Heat the mixture for 2-3 minutes. benefits while the other is neither
benefitting nor affected by the
Safety precautions relationship); mutualism (a kind
Ensure proper ventilation for of relationship where each of the
heating safely. Avoid flammable two organisms of different species
substances near the heating benefits from each other); and
parasitism (a kind of relationship

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