iGCSE Science Homework 2 Combined

Which is a characteristic of all living organisms?

• Breathing

• Eating

• Egestion

• Movement

The diagram shows a typical plant cell. What are the structures X, Y and Z?

• X- Traps light, Y- Contains genetic material, Z- Controls entry and exit of materials

• X-Traps light, Y-Site of chemical reactions, Z- Provides Support

• X-Contains genetic material, Y-Site of chemical reactions, Z- Controls entry and exit of materials

• D- Contains genetic material, Y- Controls entry and exit of materials, Z- Provides support

The statements explain the activity of a human enzyme as the temperature increases from 20 °C

to 50 °C. The statements are in the wrong order.

1 The enzyme is working at its optimum rate.

2 The kinetic energy of the enzyme molecules begins to increase.

3 The enzyme begins to change shape.

4 The enzyme is completely denatured.

What is the correct order of the statements?

• 1 → 3 → 2 → 4

• 1 → 4 → 3 → 2

• 2 → 1 → 3 → 4

• 3 → 2 → 4 → 1

Tests were performed on four samples of food. The results are shown in the table.

Which food contains protein only?

• A

• B

• C

• D

A student is investigating how light affects photosynthesis.

The student shines a light from point Y and measures the volume of gas produced in five minutes.

Which gas is produced and how does the rate of gas production change when the light is moved

from Y to X?

• Carbon dioxide, rate decreases

• Carbon dioxide, rate increases

• Oxygen, rate decreases

• Oxygen, rate increases

The diagram shows the alimentary canal.

Which label shows where bile is stored?

• A

• B

• C

• D

The graph shows the rate of water loss from a plant.

What could cause the change in the rate of water loss between point X and point Y?

• The air becomes cooler

• The air becomes drier

• The day becomes sunnier

• The stomata open wider

The table below shows some options. What are the possible causes of coronary heart disease?

• A

• B

• C

• D

During aerobic respiration of glucose, oxygen is used up and water is produced.

How many molecules of oxygen are used and how many molecules of water are produced when one molecule of glucose is respired?

• A

• B

• C

• D

Which statement about atoms and molecules is correct?

• Atoms loose or gain electrons to become molecules

• Atoms of the same element contain the same number of molecules

• Molecules are the simplest unit of an atom

• Molecules contain atoms that are covalently bonded