exam

1. 1
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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

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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

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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’?

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‘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

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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]