Salin latihan ini ke dalam buku sains 2 (SC2)

1 A group of pupils carried out an investigation to find out if microorganisms can grow. They took a slice of bread and sprinkled a few drops of water on it. The moist bread was put into a clear plastic bag and then left for one week. The result of the experiment is shown in Diagram 1.

Diagram 1

(a) What is the purpose (aim) of the investigation?

___________________________________(b) State one relationship (hypothesis) between the day and size of dark spot.

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(c) Identify the dark spots.

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(d) Suggest one way to prevent the bread from getting spoilt very fast.

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(e) Give two uses of the useful microorganisms.

1. _________________________________

2. _________________________________

Some microorganisms are very useful to mankind.

(f) State the conclusion that can be made based on the observation.

____________________________________

2 An investigation has been carried out by the following steps.1. Mix one teaspoon of sugar and two teaspoons of dried yeast with some water in a conical flask.2. Insert a balloon over the mouth of the conical flask.3. Left outside in a warm place for 20 minutes.Diagram 2 shows the conical flask containing warm water, yeast and sugar.

Diagram 2

(a) Predict what will happen after 20 minutes of investigation.

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(b) State one reason (inference) based on your answer in (a).

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(c) State another observation that can be found after 20 minutes.

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(d) State one reason (inference) based on your answer in (c).

____________________________________

(e) What can be concluded in the investigation?

___________________________________

3 The following shows a conversation between a doctor and a patient.

(a) What would X most probably be?

_______________________________________

(b) State another symptom that the patient could have faced.

___________________________________(c) What is the possible cause of the disease X?

___________________________________ [1 mark]

(d) How does this disease spread?

___________________________________ [1 mark]

(e) State two ways to prevent microorganisms from

spreading.

1.__________________________________

2.__________________________________[2 marks]

(f) State two possible contagious diseases which can be Y.

1. _________________________________

2. _________________________________[2 marks]

Patient: There are itchy red spots on my skin all over my body.

Doctor: You are infected with a disease called X. I will give you an injection and you will be alright in two days time.

Patient: Thank you, doctor.

A patient who is infected with contagious disease Y is being quarantined in a hospital.