assessment for learning

year 9

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9C Plants and photosynthesis Assessment for learning...year 9 (level 3-6) Answer all questions: Total marks 31 Time allowed 25 mins.

Question 1:

The drawing shows an experiment to investigate photosynthesis in weed from a pond.

test-tube gas

water

pond weedplasticine

funnel

beaker

Bubbles of gas produced during photosynthesis were given off from the pond weed and collected in the test tube.

(a) Name the gas given off in photosynthesis

...................................................................................................................... 1 mark

(b) What two substances are taken in by the plant and used for photosynthesis?

1. ..................................................................................................................

2. .................................................................................................................. 2 marks

Light of different intensities was shone onto the pond weed. The number of gas bubbles given off in one minute at each light intensity was counted. The results are shown in the graph.

number ofbubbles perminute

light intensity

A B C D E

(c) Which letter on the horizontal axis shows the light intensity at which the rate of photosynthesis first reaches its maximum?

............................................................ 1 mark

Blue, green and red light were then shone, in turn, onto the pond weed. The number of bubbles of the gas given off in one minute was counted. The results are shown in the table.

colour of light number ofbubbles in one

minuteblue 85

green 10red 68

The leaves of the pond weed contain a green pigment which absorbs light for photosynthesis

(d) (i) Name this pigment.

............................................................................................................. 1 mark

(ii) Using the information in the table, tick a box by one colour of light which is strongly absorbed by the pigment.

blue

green

red

1 mark

(e) Sugar is also produced during photosynthesis.

Give two ways in which the plant uses sugar.

1. ..................................................................................................................

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2. ..................................................................................................................

.................................................................................................................. 2 marks

Maximum 8 marks

Question 2:

Hydrogencarbonate indicator solution changes colour when the amount of carbon dioxide dissolved in it changes. This is shown in the table.

colour of indicatorsolution amount of dissolved carbon dioxide

reddish orange

yellow

purple

same amount of carbon dioxide as in the air

more carbon dioxide than in the air

less carbon dioxide than in the air

Five test tubes were set up as shown below. Air was bubbled through hydrogencarbonate indicator solution, which was then poured into each test tube.

The test tubes were left in sunlight for two hours.

(a) (i) What would be the colour of the indicator solution in tube A?

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1 mark

(ii) Name the process taking place in the cells of the snails which causes this colour change.

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1 mar

(b) (i) What would be the colour of the indicator solution in tube B?

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1 mark

(ii) Name the process taking place in the cells of the waterweed which causes this colour change.

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1 mark

(c) The colour of the indicator solution in tube C did not change. Explain why.

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1 mark

Tube D is wrapped to keep the light out. It contains waterweed but no snails.

(d) After twenty four hours in the dark what would be the colour of the indicator solution in tube D?

Tick the correct box.

Reddish orange

Yellow

Purple

1 mark

Maximum 6 marks

Question 3:

Some pupils grew carrot plants for a project on plant growth. At the end of the summer they dug up the carrots. The drawings show two of their carrots.

(a) Plant A came from a part of the garden which was covered with weeds. Plant B came from a part of the garden which had been kept free of weeds.

Suggest two ways in which the weeds may have stopped plant A from growing as large and healthy as plant B.

1. ......................................................................................................................

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2. ......................................................................................................................

.......................................................................................................................... 2 marks

(b) Explain why the pupils’ plants produced bigger roots when they received more light.

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.......................................................................................................................... 3 marks

Maximum 5 marks

Question 4:

Mango trees are grown in hot, dry countries where the soil can be hard and tightly compacted. Farmers water the mango trees by spraying water onto the soil around them.

(a) (i) Only a small amount of the water actually reaches the roots of the trees. Suggest one reason why.

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................................................................................................................. 1 mark

(ii) Suggest one other reason why mango trees do not grow well in soil which is hard and tightly compacted.

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................................................................................................................. 1 mark

(b) Give two reasons why mango trees and other plants need water.

1. ......................................................................................................................

..........................................................................................................................

2. ......................................................................................................................

.......................................................................................................................... 2 marks

(c) There is a new method of watering mango trees. Trenches are dug between the trees and filled with small pieces of rock. Plastic pipes with small holes in them are placed on top of the pieces of rock and water is pumped along the pipes.

Mango trees watered by this method produce 15% more fruit.

(i) Suggest one reason why pieces of rock are placed in the trenches under the pipes.

.................................................................................................................

................................................................................................................. 1 mark

(ii) With the new method, farmers can also add nitrates to the water in the pipes. Give one reason why plants need compounds which contain nitrogen.

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................................................................................................................. 1 mark

Maximum 6 marks

Question 5:

The drawing shows a ‘bottle garden’ which is kept in a brightly lit room. The cork in the neck of the bottle is not taken out.

(a) The plants in the bottle use oxygen for respiration.

Explain why, over a week, the amounts of oxygen and carbon dioxide in the bottle stay about the same.

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......................................................................................................................... 3 marks

(b) Cross-pollination is the transfer of pollen from one plant to another.

Give two reasons why cross-pollination is less likely to happen in this bottle garden than in an outdoor garden.

1. .................................................................................................................…

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2 ......................................................................................................................

......................................................................................................................... 2 marks

(c) Micro-organisms in the soil break down the dead parts of plants. This releases minerals such as nitrates. Nitrates are a source of nitrogen for living plants.

Why does a plant need nitrogen to grow?

......................................................................................................................... 1 mark

Maximum 6 marks