2015 MALAWI SCHOOL CERTIFICATE OF EDUCATION MOCK

BIOLOGY PAPER I THEORY (100 marks)

Date: Tuesday, March 17 Time Allowed: 1:30-4:00pm

Instructions: 2hours 30minutes

 This paper contains 10 pages. Please check!

 Write your name on top of each page of the question paper and other answer sheets.
 This paper contains three sections A,B and C.
 Answer all questions in all the sections.
 Some questions can be answered quickly, but others require considerable thought and may take
longer.
 Write your answers on the question in the spaces provided.
 The maximum number of marks are indicated against each question
 In the table provided on this page, tick against the question number you have answered.

Question number Tick if answered Do not write in this column

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 SECTION A (20marks)
Answer all questions in this section.
1a. Define population.
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b. Explain how population age structure affects human population growth.
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c. Mention any two processes that add carbon dioxide into the atmosphere.
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2. Figure 1 shows two plant cells taken from a leaf. Use it to answer the questions that follow:

a(i) Name the structure marked P.

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(ii) Name the process that takes place in structure marked P.

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b (i) Identify which cell would be a spongy mesophyll cell.

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(ii) Give a reason for your answer.

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c. Name one other cell in a leaf that would carry out photosynthesis.

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3. Cancer is one the diseases that is becoming in these days of HIV/AIDS.

a. Name any two risky styles that may lead to development of cancer.

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b. Name any two dangers of cancerous cells in the body.

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c. Explain why a person with HIV/AIDS easily develops cancer.

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4. Figure 2 is a diagram showing a visking tubing containing sugar solution of 10% in a beaker of distilled
water. Use it to answer the questions that follow.

a. (i) State what will happen to the level of the solution after 20 minutes.
_________________________________________________________________________ 1mark
(ii) Give a reason for your answer.
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b. Give any three adaptations that small intestines have which are not shown in the visking tubing.
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 SECTION B (60marks)
Answer all questions in this section.
5. Figure 3 shows an equation that summarises two chemical processes in living cells. Use it to
answer the questions that follow:
Glucose + Oxygen Carbon dioxide + Water + Energy
a. Name the process marked Q.
_________________________________________________________________________1mark
b. State the organelle in which the process marked P occurs.
_________________________________________________________________________1mark
c. Give the form of energy released the process marked P.
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d. What is the role of stomata in controlling the water loss from plant leaves.
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6. Figure 4 shows two neurons involved in the reflex arc. Use it to answer the questions that follow:

a. (i) Name the neurone marked A.

________________________________________________________________________________1mark

(ii) Give a reason for your answer.

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(iii) Draw an arrow in the diagram to show the direction of an impulse. 1mark

b.Name the part marked B.

_______________________________________________________________________________1 mark

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 c. Explain how the impulses cross the synapse.
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(ii) Explain why it is important for the neurotransmitter to be destroyed after starting an impulse across
the synapse.

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7. Figure 5 is a diagram showing the patient’s temperature when suffering from a protozoan disease.
Use it to answer the questions that follow:

a. What symptom is shown by the disease on the graph.

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b. How long was the incubation period.

_________________________________________________________________________ 1mark
c. Suppose the disease was malaria, what would have caused the rise in temperature?
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d. State any two factors that are considered before an organ transplant.
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8a. Define the term Extensor Muscle.

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(ii) Give any one example of a Flexor Muscle.

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b. Name the substance that is used to change cartilage into hard bone.

_______________________________________________________________________________ 1mark

c .Name two places in the body where cartilage is found.

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9. Figure 6 is a diagram showing blood cells on a microscope slide. Use it to answer the questions that
follow:

a. How many white blood cells can be seen on the slide?

________________________________________________________________________1mark
b. Give any one function of the red blood cells.
________________________________________________________________________ 1mark
c. Red blood cells are produced in the bone marrow at an average of once in 100 days.
(i) Explain why red blood cells do not reproduce.
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(ii) 1 mm of blood contains 5million red blood cells. How many red blood cells does 1 cm
contain. Show your working. 2marks

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10. In a certain breed of cattle, coat colour may be red, white or roan. Roan is a mixture of red and
white. Using R to represent allele for red and W to represent allele for white.

a. What are the genotypes of the following:

Red:____________________________________________________________________________1mark

White:__________________________________________________________________________1mark
Roan:__________________________________________________________________________1mark

b(i) Draw a well labelled genetic diagram to show the cross of between roan cattle.

3marks

(ii).State the genotypic ratio offsprings.

_______________________________________________________________________________1mark

c.What is the probability of a roan cattle being produced from a red bull and white cow?

_________________________________________________________________________1mark

11. a(i) Name the chemical in the blood that causes changes in human breathing.

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(ii). State one change that occurs to breathing when this chemical is higher than usual in the blood.

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b. Explain the effects of the following substances in tobacco smoke on a healthy human being:

(i)Tar:________________________________________________________________________________
_______________________________________________________________________________2marks

Carbon monoxide:_______________________________________________________________
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12a. State the theory of Evolution as outlined by Charles Darwin.

(i) Struggle for existence:___________________________________________________

______________________________________________________________________________2marks

(ii) Over production:____________________________________________________________

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13a. Name a substance in ovaries responsible for the release of progesterone.

________________________________________________________________________________1mark

b. What is the effect of the hormone oestrogen on the uterus?

________________________________________________________________________________1mark
c. Define the term contraception.

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d. Explain any two adaptations of the placenta to its function.

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14. Figure 7 shows a longitudinal section of a plant tissue. Use it to answer the questions that follow:

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 a. Identify the tissue shown in the diagram.
_________________________________________________________________________ 1mark
b. State the function of the part marked J.
_________________________________________________________________________1mark
c. Name two substances transported by the tissue shown in the diagram.
______________________________________________________________________________
________________________________________________________________________ 2marks
d. Mention two adaptations of the tissue in the figure 7 to its function.
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________________________________________________________________________2marks

SECTION C
Essay Questions

Answer both questions in this sections.

15. Discuss the effects of physical exercises on breathing in human beings.

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16. Explain the mechanism of osmoregulation in the human body.

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END OF QUESTION PAPER

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