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c

Student’s Name: ………………………………. Index: ……………. Class…………….

MID-EXAM

BIOLOGY

GRADE – 8

Total Marks: 50 Duration: 50 minutes First Term – 2010

This document consists of 7 printed pages.

Section A [Total:10m]

Answer all the questions by drawing a circle on the correct answer.

1. The diagram shows a plant cell as seen under a microscope.

What are the functions in the cell of the numbered parts?

Control the entry of

substances

Synthesis of

carbohydrates

A

B

C

D

1

2 3

3

3

1

2

1

2. A chemical molecule contains sulphur and phosphorous. Which of the following could

it be?

A. A carbohydrate

B. A fatty acid

C. A protein

D. Glycerol

3

2

1

2

3. Which description applies for a red blood cell?

Cell wall Nucleus

A

B

C

D

Absent

Absent

Present

Present

Absent

Present

Absent

Present

4. Some substances in living organisms move by active transport. Which line is correct

for active transport?

A. Movement of substances from low concentration to high concentration by using

energy.

B. Movement of substances from low concentration to high concentration without

using energy.

C. Movement of substances from high concentration to low concentration by using

energy.

D. Movement of substances from high concentration to low concentration without

using energy.

5. Which structures in a plant cell contain DNA and cellulose?

DNA Cellulose

A

B

C

D

Cell wall

Chloroplast

Cytoplasm

Nucleus

Cytoplasm

Nucleus

Chloroplast

Cell wall

6. A flexible cell membrane is necessary for which one of the following to carry out its

function?

A. Palisade cell

B. Red blood cell

C. Root hair cell

D. Xylem vessel

3

7. The diagram below shows, in order, four stages in which an enzyme controlled

chemical reaction may occur.

M N O P

A

B

C

D

Enzyme

Substrate

Substrate

Active site

Active site

Product

Active site

Enzyme

Substrate

Enzyme

Enzyme

Product

Product

Active site

Product

Substrate

8. Which of the following is needed for the transport of oxygen by red blood cells?

A. Contractile fibres

B. Haemoglobin

C. Nucleus

D. Thick outer wall

9. The concentration of nitrate ions in a root cell is higher than in the surrounding soil

solution.

How do the nitrate ions move into the root cell?

A. Active transport

B. Diffusion

C. Osmosis

D. Transpiration

10. Starch is digested to maltose by the enzyme amylase.

According to the ‘lock’ and ‘key’ hypothesis, which is the ‘key’ and which is the ‘lock’?

4

‘key’ ‘lock’

A

B

C

D

Amylase

Amylase

Starch

Starch

Maltose

Starch

Amylase

Maltose

Section B

Answer all the questions.

1. The diagram below shows a cell seen under a microscope.

a) Name the type of cell shown in the diagram.

………………………………………………………………………………………………...[1m]

b) Name, on the diagram, the structures labeled A, B, C and D. [4m]

c) Which two of the structures labeled A, B, C and D would you not find in a human

cheek cell?

……………………………………………………………………………………….………..[2m]

d) What is the function of the structure A?

………………………………………………………………………………………….……..[1m]

e) What is the most important constituent found in the structure D?

………………………………………………………………………………………………...[1m]

f) What is the storage molecule of this cell?

…………………………………………………………………………………………………[1m]

A

B

C

D

5

g) The storage molecule of this cell comes under which type of biological molecule?

………………………………………………………………………………………………...[1m]

[Total: 11m]

2. a) Organisms are made up of cells, organs, organ systems and tissues.

In the table below, list these four terms in order of increasing size. Write down an

example of each term next to its name. [6m]

Term Example from plant Example from animal

b) The following diagram shows different types of cells observed under a light

microscope.

i. Which one of the above cells is capable of active movement?

…………………………………………………………………………………………[1m]

ii. Which labeled cells do not have a nucleus?

………………………………………………………………………………………...[1m]

iii. How does the absence of the nucleus help each of the cells suggested in their

functions?

………………………………………………………………………………………………

………………………………………………………………………………………………

…………………………………………………………………………………………[2m]

A B C D

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iv. A specialized feature is found in one of the cells above that is responsible for

mechanical support of a leaf and transport of water into the leaf.

Which cell is it and what is the specialized feature?

………………………………………………………………………………………...[2m]

[Total: 12m]

3. The figure below shows one cell placed in different solutions. The cell A is a plant cell

at the start of the experiment. The cell B and C show the appearance of the same plant

cell after ten minutes but in two different solutions.

a) Write any two visible difference between cells A and C.

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

……………………………………………………………………………………………..….[2m]

b) What structure of the cell is responsible for these changes?

…………………………………………………………………………………………………[1m]

c) What is the liquid surrounding the cell B?

…………………………………………………………………………………………..…….[1m]

d) Give the name of the condition shown by

Cell B…………………………………………

Cell C………………………………………… [2m]

e) What process is responsible for the changes in the cells B and C?

…………………………………………………………………………………………………[1m]

Cell A Cell B Cell C

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f) Define the process that you suggested in question (e)

………………………………………………………………………………………………………

………………………………………………………………………………………………...[1m]

g) Write one example of this process in plants.

…………………………………………………………………………………………………[1m]

[Total: 9m]

4. a) Define the following

i. Active transport

…………………………………………………………………………………………

………………………………………………………………………………….…[1m]

ii. Phagocytosis

…………………………………………………………………………………………

………………………………………………………………………………….…[1m]

iii. Metabolism

…………………………………………………………………………………………

…………………………………………………………………………………….[1m]

iv. Catabolism

…………………………………………………………………………………………

…………………………………………………………………………………….[1m]

b) Explain the ‘lock’ and ‘key’ hypothesis.

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

………………………………………………………………………………………………………

…………………………………………………………………………………………………[4m]

[Total: 8m]