Questions Q1.

Plant growth substances

Photograph A shows the root of a plant when it was positioned horizontally.

The root was kept in the dark and left in this position.

Photograph B was taken three days later.

(a) (i) Complete the sentence by putting a cross ( ) in the box next to your answer.

The process that resulted in the type of root growth shown in photograph B is (1)

A negative gravitropism B negative phototropism C positive gravitropism D positive phototropism

(ii) Explain how this change in root growth has occurred.

(3) .............................................................................................................................................

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(iii) Suggest the advantages to the plant of this response.

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(b) Rebecca and Andrew each set up an experiment to investigate the effect of light on plant shoots.

They also set up a control experiment. Rebecca placed a black cap over the tip of her plant shoot. Andrew removed the tip from his plant shoot, placed a thin block of jelly on top of the plant shoot and then replaced the tip. All three experiments were left for 24 hours.

(i) Suggest why Rebecca and Andrew set up a control experiment.

(1) .............................................................................................................................................

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(ii) Explain the results of Rebecca's experiment and Andrew's experiment.

(3) .............................................................................................................................................

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(Total for question = 10 marks)

Q2.

Auxins are plant hormones.

(a) (i) Complete the sentence by putting a cross ( ) in the box next to your answer. Auxins cause the shoot of a plant to grow towards light in a process called

(1) A negative gravitropism B negative phototropism C positive gravitropism D positive phototropism

(ii) Explain how auxins cause the shoot of a plant to grow towards light. (2)

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Ethylene (ethene) is a plant hormone that stimulates the ripening of fruit. The graph shows the effect of ethylene (ethene) concentration on the ripening of bananas after three days.

(i) Describe the effect of ethylene (ethene) on the ripening of bananas.

(1) .............................................................................................................................................. .............................................................................................................................................. (ii) Explain which concentration of ethylene (ethene) a supermarket should use to be most cost effective when ripening bananas.

(2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. ..............................................................................................................................................

*(c) Fruit ripening is one use of plant hormones. Describe the other uses of plant hormones in crop production.

(6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. ..............................................................................................................................................

(Total for Question is 12 marks)

Q3. Faiza investigated the effect of rooting powder on plant cuttings.

She did not add rooting powder to one cutting.

She treated two more plant cuttings with different concentrations of rooting powder.

All three cuttings were then planted.

The diagrams show the cuttings after they had been growing for five weeks.

Faiza measured the length of four individual roots from each of the plants treated with rooting powder. Her results are shown in the table.

percentage rooting powder (%)

root length / cm

1 2 3 4 Mean

2 0.9 1.4 1.0 1.1 5 2.3 2.5 1.3 3.1 2.3

(i) Calculate the mean root length for the 2% rooting powder. (1)

answer = .............................................................................cm (ii) Compare the mean root length in 2% with the mean root length in 5% rooting powder.

(1) .............................................................................................................................................. ..............................................................................................................................................

Q4. Plant hormones

(a) Faiza investigated the effect of rooting powder on plant cuttings.

She did not add rooting powder to one cutting.

She treated two more plant cuttings with different concentrations of rooting powder.

All three cuttings were then planted.

The diagrams show the cuttings after they had been growing for five weeks.

Describe the effect of rooting powder on the growth of these plant cuttings.

(2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. ..............................................................................................................................................

(b) Faiza measured the length of four individual roots from each of the plants treated with rooting powder. Her results are shown in the table.

percentage rooting powder (%)

root length / cm

1 2 3 4 Mean

2 0.9 1.4 1.0 1.1 5 2.3 2.5 1.3 3.1 2.3

(i) Calculate the mean root length for the 2% rooting powder. (1)

answer = .............................................................................cm (ii) Compare the mean root length in 2% with the mean root length in 5% rooting powder.

(1) .............................................................................................................................................. ..............................................................................................................................................

(c) (i) Complete the sentence by putting a cross ( ) in the box next to your answer.

The response of roots to gravity is called

(1) A gravitropism B homeostasis C photosynthesis D phototropism

(ii) Explain how roots respond to gravity. (2)

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(d) Rooting powder contains plant hormones.

Plant hormones are used extensively in the food production industry.

Describe some benefits of using plant hormones, other than rooting powder, in the food production industry.

(3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. ..............................................................................................................................................

Q5.

Auxins are plant hormones.

(i) Complete the sentence by putting a cross ( ) in the box next to your answer. Auxins cause the shoot of a plant to grow towards light in a process called

(1) A negative gravitropism B negative phototropism C positive gravitropism D positive phototropism

(ii) Explain how auxins cause the shoot of a plant to grow towards light. (2)

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Q6. Faiza investigated the effect of rooting powder on plant cuttings.

She did not add rooting powder to one cutting.

She treated two more plant cuttings with different concentrations of rooting powder.

All three cuttings were then planted.

The diagrams show the cuttings after they had been growing for five weeks.

Describe the effect of rooting powder on the growth of these plant cuttings.

(2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. ..............................................................................................................................................

Mark Scheme Q1.

Q2.

Answer Acceptable answers Mark

(a)(i) D positive phototropism

(1)

(a)(ii) An explanation to include the following linked points (auxins) move to the shaded side of a shoot (1) causing cells on the shaded side to elongate (1)

accept move to the side opposite the light accept get longer for elongate Ignore references to cell division (2)

(b)(i) there is an increase in the % of bananas that ripen as the ethylene concentration increases

Ignore positive effect

(1) (b)(ii) An explanation to

include two of the following points • concentration of ethylene to use is 3% (1) • would be more expensive to increase the ethylene concentration above 3% • when there is no added ripening benefits past 3%(1) • below 3% not all bananas are ripe (1)

Do not credit ideas related to longer shelf life as the question asks about ripening (2)

Indicative Content Mark

QWC *(c) A description to include some of the following points • selective weedkillers • allows broad-leaved plants to grow uncontrollably and die • narrower-leaved plants and crops left unaffected • auxins and or gibberellins are used • rooting powders • plant cuttings are dipped into rooting (6)

powder • roots develop rapidly • large number of plants can be produced from the same plant • no need to wait for plants to grow from seeds • auxins are used • seedless fruit production • the fruit will develop but the seeds inside will not • fruits are able to grow larger (larger biomass) • gibberellins are used

Level 0 No rewardable content 1 1 - 2

• a limited description of at least one use of plant hormones • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy

2 3 - 4 • a simple description of two or more uses of plant hormones • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed description of two or more uses of plant hormones with at least auxin, gibberellins or other relevant hormone in the correct context • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors

Total for question = 12 marks

Q3.

Question Number

Answer Acceptable answers Mark

(i) = 1.1(cm) Accept answer written in table (1)

Question Number

Answer Acceptable answers Mark

(ii) the mean value for 5% rooting powder shows a longer root than the mean value for 2% / ORA

Accept accurate interpretation of data

(1)

Q4.

Question Number

Answer Acceptable answers Mark

(a) A description including two of the following points • more / bigger / longer roots are grown in (2% / 5%) powder compared to no powder (1) • bigger / taller plants are grown in (2% / 5%) powder compared to no powder (1) • more / bigger leaves are grown in (2% / 5%) powder compared to no powder (1)

(2) Question Number

Answer Acceptable answers Mark

(b)(i) = 1.1(cm) Accept answer written in table (1)

Question Number

Answer Acceptable answers Mark

(b)(ii) the mean value for 5% rooting powder shows a longer root than the mean value for 2% / ORA

Accept accurate interpretation of data

(1) Question Number

Answer Acceptable answers Mark

(c)(i) A (1) Question Number

Answer Acceptable answers Mark

(c)(ii) An explanation linking two of the following points • roots bend towards gravity/roots bend downwards/grow down (1) • auxin distributed to lower side/underside of root (1) • auxin inhibits growth (causing this downward bend) (1)

(2)

Question Number

Answer Acceptable answers Mark

(d) A description including the following points

(3)

• selective weed killers result in higher crop yield (1) • seedless fruit are more desirable to consumers / increase turnover (1) • fruit ripening can be controlled so less wastage / link to demand (1)

Answer Acceptable answers Mark

(i) D positive phototropism

(1)

(ii) An explanation to include the following linked points (auxins) move to the shaded side of a shoot (1) causing cells on the shaded side to elongate (1)

accept move to the side opposite the light accept get longer for elongate Ignore references to cell division (2)

Question Number

Answer Acceptable answers Mark

A description including two of the following points • more / bigger / longer roots are grown in (2% / 5%) powder compared to no powder (1) • bigger / taller plants are grown in (2% / 5%) powder compared to no powder (1) • more / bigger leaves are grown in (2% / 5%) powder compared to no powder (1)

(2)