Planning Investigations Qs

Q1.To be healthy, plants need the right amount of mineral ions from the soil.

The diagram below shows four plants.

The plants were grown in four different growing conditions:

•        sunny area, with nitrate and magnesium added to the soil

•        sunny area, with magnesium but no nitrate added to the soil

•        sunny area, with nitrate but no magnesium added to the soil

•        dark area, with nitrate and magnesium added to the soil.

 

(a)     Which plant was grown with no nitrate? 

Tick one box.   

A   B   C   D

(1)

(b)     Which plant was grown with no magnesium? 

Tick one box.   

A   B   C   D

(1)

(c)     Give one variable that was kept constant in this experiment.

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(d)     Plants need other minerals for healthy growth such as potassium ions and phosphate ions.

A farmer wanted to compare the percentage of minerals in two types of manure.

•        Cow manure from her own farm.

•        Chicken manure pellets she could buy.

The table below shows data for each type of manure. 

  Phosphate ions in %

Potassium ions in %

Cow manure 0.4 0.5

Chicken manure pellets 2.5 2.3

Suggest one advantage and one disadvantage of using the chicken manure pellets compared to the cow manure.

Advantage _________________________________________________________

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Disadvantage _______________________________________________________

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(Total 5 marks)

Q2.Plants transport water and mineral ions from the roots to the leaves.

(a)     Plants move mineral ions:

•        from a low concentration in the soil

•        to a high concentration in the root cells.

What process do plants use to move these minerals ions into root cells? 

Tick one box.  

Active transport

Diffusion

Evaporation

Osmosis

(1)

(b)     Describe how water moves from roots to the leaves.

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(c)     Plants lose water through the stomata in the leaves.

The epidermis can be peeled from a leaf.

The stomata can be seen using a light microscope.

The table below shows the data a student collected from five areas on one leaf. 

Leafarea

Number of stomata

Upper surface

Lower surface

1 3 44

2 0 41

3 1 40

4 5 42

5 1 39

Mean 2   X

Describe how the student might have collected the data.

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(d)     What is the median number of stomata on the upper surface of the leaf?

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(e)     Calculate the value of X in the table.

Give your answer to 2 significant figures.

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Mean number of stomata on lower surface of leaf = _____(2)

(f)     The plant used in this investigation has very few stomata on the upper surface of the leaf.

Explain why this is an advantage to the plant.

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(Total 11 marks)

Q3.A student plans an investigation using mould.

(a)     Mould spores are hazardous.

Give one safety precaution the student should take when doing this investigation.

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(b)     A student made the following hypothesis about the growth of mould:

‘The higher the temperature, the faster the growth of mould’.

The student planned to measure the amount of mould growing on bread.

The student used the following materials and equipment:

•        slices of bread

•        sealable plastic bags

•        a knife

•        a chopping board

•        mould spores.

Describe how the materials and equipment could be used to test the hypothesis.

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(c)     Give one variable the student should control in the investigation.

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(d)     Another student did a similar investigation.

The diagram below shows the results.

 

Determine the rate of mould growth at 42 °C between day 2 and day 7.

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Rate of mould growth = _______________ units per day(2)

(e)     The growth of mould shows decomposition of the bread.

Give a conclusion about decomposition from the results in the diagram above.

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(Total 9 marks)

Q4.Biological detergents contain protease enzymes.

(a)     The drawings show some apparatus and materials.

In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Describe how you would use the apparatus and materials shown in the drawings to find the best temperature for removing stains from clothing.

You should include how you would make the investigation a fair test.

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(b)     In a similar investigation a student investigated the effect of pH on the time taken to remove a stain from pieces of cloth.

The table shows the student’s results. 

      pH of detergent solution

  1 2 3 4 5 6 7 8 9

Time taken to removestain in minutes

20 19 17 14 10 4 8 12 16

(i)      On the graph paper below draw a graph to show the student’s results.

•        Add a suitable scale and label to the y axis.

•        Plot the student’s results.

•        Draw a line of best fit.

pH of detergent solution(4)

(ii)     Which is the best pH for using the detergent?

pH _____________________________(1)

(c)     Scientists investigated the stability of a protease enzyme. The protease enzyme was

extracted from plants.

The scientists:

•        pre-incubated samples of the enzyme at various temperatures for 30 minutes

•        put each sample on ice for a further 10 minutes

•        measured the percentage (%) remaining activity of the enzyme in each sample.This was done by incubating each sample with protein at 37 °C for 6 hours.

The graph shows the scientists’ results.

                Pre-incubation temperature in °C

The scientists recommended that the enzyme could be used in detergents at a temperature of 60 °C.

Suggest why the scientists recommended a temperature of 60 °C.Use information from the graph and your own scientific knowledge in your answer.

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(Total 14 marks)

Q5.(a)     When a seed starts to grow, the young root grows downwards towards gravity.The young shoot grows upwards, away from gravity.

(i)      Name this type of plant response to gravity.

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(ii)     Give two reasons why it is useful for a young root to grow towards gravity.

1. ____________________________________________________________

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2. ____________________________________________________________

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(iii)    The root grows towards gravity due to the unequal distribution of a substance in the root.

Draw a ring around the correct answer to complete the sentence. 

This substance is

auxin.

chlorophyll.

sugar.

(1)

(b)     The drawings show some apparatus and materials.

 

In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Describe how the students could use some or all of the apparatus and materials shown in the drawings to investigate the growth response of maize seedlings to light shining from one side.

You should include a description of the results you would expect.

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(Total 10 marks)

Q6.The image below shows some cells on the lower surface of a leaf.

 © Stefan Diller/Science Photo Library

(a)     What are the cells labelled X called?

Draw a ring around the correct answer.

guard cells                palisade cells                mesophyll cells(1)

(b)     Water loss by evaporation from leaves is called transpiration.

A student set up an experiment to investigate water loss from leaves.

The student:

•        took two leaves, A and B, from a plant

•        put Vaseline (grease) on both sides of Leaf B; did nothing to Leaf A

•        wrote down the mass of each leaf

•        attached the leaves onto a string as shown in the diagram below.

 

Leaf A(no treatment)

Leaf B(both surfaces

covered in Vaseline)

•        left the leaves for 48 hours

•        wrote down the mass of each leaf again

•        calculated the percentage (%) change in mass for each leaf.

(i)      Give one variable that the student controlled in this investigation.

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(ii)     The mass of Leaf A was 1.60 g at the start of the investigation. After 48 hours it was 1.28 g.

Calculate the % decrease in mass over 48 hours.

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% decrease = __________________(2)

(c)     Vaseline blocks the stomata.

The % change in mass of Leaf B was less than Leaf A after 48 hours.Explain why.

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(d)     Give three environmental conditions that would increase transpiration.

1. _________________________________________________________________

2. _________________________________________________________________

3 _________________________________________________________________(3)

(Total 8 marks)

Q7.In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Light intensity, carbon dioxide concentration and temperature are three factors that affect the rate of photosynthesis.

How would you investigate the effect of light intensity on the rate of photosynthesis?

The image below shows some of the apparatus you might use.

 

You should include details of:

•        how you would set up the apparatus and the materials you would use

•        the measurements you would make

•        how you could make this a fair test.

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Mark schemes

Q1.(a)     A

1

(b)     D1

(c)     use the same type of plantorgive equal amount of water to each plant

ignore size of pot1

(d)     (advantage) more minerals1

(disadvantage) cost / not free1

[5]

Q2.(a)     active transport

1

(b)     by transpiration stream / pull1

in xylem1

(c)     any three in the correct order from:•        mount epidermis on a slide•        count stomata in one area•        repeat in four more areas•        repeat method on other surface of leaf•        calculate mean

allow nail varnish film3

(d)     1allow numbers written out in a line with middle number circled

1

(e)     (44 + 41 + 40 + 42 + 39) / 5 = 41.21

41allow 41 with no working shown for 2 marks

1

allow 41.2 for 1 mark

(f)     less water lost1

so it does not wilt

1[11]

Q3.(a)     wear a face mask

allow wear gloves1

(b)     Level 2 (3–4 marks):A detailed and coherent plan covering all the major steps. It sets out the steps needed ina logical manner that could be followed by another person to produce an outcome whichwill address the hypothesis.

Level 1 (1–2 marks):Simple statements relating to steps are made but they may not be in a logical order. The plan may not allow another person to produce an outcome which will address the hypothesis.

0 marks:No relevant content.

Indicative content

Plan:•        cut a specified number of pieces of bread to the same size•        place mould spores on the bread•        the number of mould spores needs to be the same quantity of mould spores

oneach piece of bread

•        place bread in different sealable plastic bags•        place in different temperatures (minimum of three) eg fridge, room, incubator•        leave each for the same amount of time eg four days•        measure the percentage cover of mould on each piece of bread•        repeat experiment

additional examiner guidance:•        good level 2 answer will describe how the growth of mould can be measured

andwill give a range of different temperatures to be used

•        allow equivalent levels of credit for alternative methodologies that would clearly produce a measurable outcome in terms of mould growth at various temperatures

4

(c)     any one from:•        type of mould•        amount of mould (put on each piece of bread)•        amount of air in the plastic bags•        size of the pieces of bread•        type of bread•        amount of moisture / water added

1

(d)     (56 − 4 = 52) / 51

10.4

allow 10.4 with no working shown for 2 marks1

ecf for incorrectly read figures for 1 mark

(e)     (decomposition occurs at a faster rate when the temperature is higheroramount of decomposition is higher when temperature is higher

1[9]

Q4.(a)     Marks awarded for this answer will be determined by the Quality of Communication

(QC) as well as the standard of the scientific response. Examiners should also refer to the information on page 5, and apply a ‘best − fit’ approach to the marking.

0 marksNo relevant content.

Level 1 (1 − 2 marks)The method described is weak and could not be used to collect valid results however does show some understanding of the sequence of an investigation.

Level 2 (3 − 4 marks)The method described could be followed and would enable some results to be collected but lacks detail.

Level 3 (5 − 6 marks)The method described could be easily followed and would enable valid results to be collected.

examples of biology points made in the response:

•        (use of measuring cylinder to) measure equal volumes of detergent solution•        (use of dropping bottle to) apply same number of drops / amount of stain to

each piece of cloth•        include stainless cloth as control•        use of forceps to transfer cloths•        use of test tubes as containers for detergent solution + stained cloth•        use water bath to provide a range of temperatures•        cloths left in detergent solution at each temperature•        for same length of time or measure time taken to remove stain•        repetition•        assessing the stain removal

6

(b)     (i)      y axis: labelled ‘Time (taken to remove stain in) minutes’ plus suitable scale

data spread greater than half of grid1

points or bars plotted correctly to within ± 1 mmdeduct 1 mark for each incorrect plot up to a maximum of 2

2

one suitable line of best fit drawn on graphnot featherynot extrapolated to (0,0)not point to point as on this occasion it is inappropriate

1

(ii)     6 ± 0.1accept ecf from student graph

1

(c)     activity of enzyme still very high / 84% / over 80%oronly lost 15% / 16% activity

allow above 60 °C marked decrease in activityallow 85%

1

any two from:

•        rate of reaction high at 60 °C / higher than at lower temperaturesallow in terms of reaction kinetics / collisions

•        higher temperatures would increase (energy) costsormight damage cloth

ignore enzyme denaturation•        higher temperatures / 60 °C is better (than lower temperatures) to remove

other stains / named stains

orbetter for killing bacteria / infection control

eg grease2

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Q5.(a)     (i)      gravitropism / geotropism

not ‘…trophism’ignore ‘positive’ or ‘negative’

1

(ii)     any two from:

•        anchorage•        takes in water•        takes in ions / minerals / salts / correct named example

allow nutrientsdo not accept food

2

(iii)    auxin1

(b)     Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response.Examiners should also refer to the information on page 5, and apply a best-fit approach to the marking.

0 marksNo relevant content.

Level 1 (1 – 2 marks)There is a basic description of a simple method involving seedlings and light.

Level 2 (3 – 4 marks)There is a description of a method involving seedlings in 1-sided light, and a control, with a correct observation.

Level 3 (5 – 6 marks)There is a description of a method involving groups of seedlings in 1-sided light, and in control conditions. It includes some correct measurements or observations.

examples of Biology points made in the response:

•        use of scissors to cut tips from some shoots / cut hole in box•        use of forceps for handling seedlings•        use of ruler to measure lengths of shoots at start and at end•        other factors controlled – eg temperature / water•        use of lamp + box re. one-sided lighting•        repetitions – each treatment ≥ 3 times•        control in total darkness / all-round light•        time taken = several hours to a few days•        sample results: tip exposed to 1-sided light→bend to light, tip

removed→vertical, control→vertical6

[10]

Q6.(a)     guard cells

1

(b)     (i)      any one from:

•        species / plant•        length of time

ignore temperature and size of leaves1

(ii)     20correct answer = 2 marks

accept 

or                    for 1 mark

2

(c)     less water loss / transpiration / evaporation1

(d)     hot1

ignore bright / sunny conditions

dry / low humidity1

wind(y)1

[8]

Q7.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a ‘best-fit’ approach to the marking.

Level 3 (5–6 marks):A description of how the apparatus is used to measure the rate of photosynthesis at different light intensities is given.

For full marks reference must be made to a control variableorrepeats

Level 2 (3–4 marks):A description of how the apparatus is set upanda description of how photosynthesis can be measured.ora description of how light intensity is variedora control variable or any other relevant point

Level 1 (1–2 marks):A partial description of how the apparatus is set upora description of how light is suppliedora simple description of how photosynthesis can be measured.ora control variable

0 marks:No relevant content.

examples of the points made in the response:•        apparatus set up:

– weed in water in beaker– light shining on beaker

•        method of varying the light intensity–eg changing distance of lamp from plant•        method of controlling other variables

– use same pond weed or same length of pond weed– temperature: water bath or heat screen– CO2

•        leave sufficient time at each new light intensity before measurements taken•        method of measuring photosynthesis – eg counting bubbles of gas released or

collecting gas and measuring volume in a syringe•        measuring rate of photosynthesis by counting bubbles for set period of time•        repetitions

extra information:allow information in the form of a diagram

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