QUESTION 1
Some learners cut 12 shoots, about 15 cm long, from young bean plants. They removed
the leaves from the lower 5 cm of the cut stems. They divided the stems into three
groups, which they labelled A, B and C. They treated it each group as follows:
They planted group A in potting soil.
They dipped group B into rooting hormone powder that contained 5mg/L artificial auxin.
Then they planted the shoots in potting soil.
They dipped group C into rooting hormone powder that contained 50mg/L artificial
auxin. Then they planted the shoots in potting soil.
1.1 give a suitable hypothesis for this investigation.
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………………………………………………………………………………………………......(2)
1.2 Which group is a control.
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…………………………………………………………………………………………………..(1)
1.3 Why do you need a control.
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…………………………………………………………………………………………………..(2)
1.4 What is the independent variable.
……………………………………………………………………………………….................(1)
1.5 What is the dependent variable.
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…………………………………………………………………………………………………(1)
1.6 which variables are controlled.
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………………………………………………………………………………………………….(3)
1.7 What happens in bean cuttings in each group.
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………………………………………………………………………………………………….(4)
1.8 what conclusion can you reach from this investigation.
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………………………………………………………………………………………………….(2)
1.9 would the shoots continue to produce more roots if you kept on increasing the
concentration of the auxin in the rooting hormone powder? Explain your answer.
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…………………………………………………………………………………………………(4)
1.10 What is tropism.
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…………………………………………………………………………………………………(1)
TOTAL QUESTION 1: 21
QUESTION 2
A clinostat is a device used to investigate plant growth responses. It has a disc that
rotates very slowly when the clinostat is switched on.
During an investigation on plant responses to light, the procedure below was followed.
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Three pot plants of the same species were used.
Each pot plant was placed on one of three identical clinostats.
Each set of apparatus , A,B and C, was placed in a box with a single opening.
Each clinostat was treated in a different way over a period of five weeks.
The results of the investigation are represented in the diagrams below.
2.1 Name the plant growth response to light.
…………………………………………………………………………………………………..(1)
2.2 state two factors that were kept constant during an investigation.
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………………………………………………………………………………………………….(2)
2.3 Give one reason why the results of this investigation may be considered as reliable.
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………………………………………………………………………………………………….(1)
2.4 In which apparatus (A,B or C) was the clinostat :
a) Switched on and rotating slowly.
…………………………………………………………………………………………………(1)
b) Switched off, but maually rotated through 180° once a week.
…………………………………………………………………………………………………(1)
2.5 Explain the effect of unilateral light on the distribution of auxins in the plant in
apparatus C.
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…………………………………………………………………………………………………..(3)
TOTAL QUESTION 2: 9
GRAND TOTAL
: 30
LIFE SCIENCES
RESPONDING TO THE
ENVIRONMENT:
PLANTS
AUGUST 2019
GEORGETOWN HIGH SCHOOL
23 JANUARY
GRADE 12 2019
MARKS
: 30
TIME
: 30 MINUTES
EXAMINERS
: Mr Z.M. MNCUBE and Mr T.I MKHIZE
MODERATOR
: Mrs. THENJWAYO
INSTRUCTIONS:
 READ QUESTIONS CAREFULLY BEFORE ANSWERING.
 ANSWER ALL QUESTIONS.
 NUMBER YOUR ANSWERS EXACTLY AS YOUR QUESTIONS ARE NUMBERED.