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B4 Bioenergetics35 Questions

Name: ________________________

Class: ________________________

Date: ________________________

Time:

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of 107Brookvale Groby Learning Trust

Respiration can happen aerobically or anaerobically.

Respiration transfers energy from glucose.

(a) Draw one line from each type of respiration in human cells to the correct information.

Type of respirationin human cells

Information

Produces ethanol

Aerobic respiration Uses oxygen

Anaerobic respiration Uses carbon dioxide

Produces lactic acid

(2)

1

(b) The table below shows the amount of energy released by aerobic and anaerobicrespiration.

Energy in kJ transferred

from 1 g of glucose

Aerobic respiration 16.1

Anaerobic respiration 1.2

Suggest why human cells might respire anaerobically, even though only a small amount ofenergy is transferred.

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(1)


(c) Yeast is used in the brewing and baking industries.

Why is yeast used in these industries?

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(4)

(Total 7 marks)

Some students investigated how exercise affects heart rate.

The figure below shows their results.

(a) What was Student B’s resting heart rate?

Resting heart rate = _______________ beats per minute

(1)

2


(b) The students started running at 2 minutes.

What evidence for this is in the figure above?

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(1)

(c) For how many minutes did the students run?

Tick one box.

2

4

6

14

(1)

(d) Student B is fitter than Student A.

Use the figure above to give two pieces of evidence that support this statement.

1. _________________________________________________________________

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2. _________________________________________________________________

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(2)


(e) There are other changes in the body during exercise.

Explain why these changes occur.

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(4)

(Total 9 marks)

Pathogens cause infectious diseases in animals and plants.

(a) Draw one line from each disease to the type of pathogen that causes the disease.

Disease Type of pathogen

Bacterium

Gonorrhoea

Fungus

Malaria

Protist

Measles

Virus

(3)

3


(b) Some parts of the human body have adaptations to reduce the entry of live pathogens.

Look at Figure 1.

Figure 1

Explain how the trachea is adapted to reduce the entry of live pathogens.

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(4)


(c) Malaria is a serious disease that can be fatal.

Malaria is spread to humans by infected mosquitoes.

Scientists investigated the behaviour of mosquitoes to understand how the spread ofmalaria could be controlled.

Figure 2 shows the equipment the scientists used.

Figure 2

This is the method used.

1. 30 mosquitoes infected with malaria were placed in Container A.

2. 30 uninfected mosquitoes were placed in Container B.

3. The total number of times the mosquitoes landed on the socks was recorded.

Name the dependent variable and suggest one control variable in this investigation.

Dependent variable ___________________________________________________

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Control variable ______________________________________________________

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(2)


(d) Infected mosquitoes landed on the socks three times more often than uninfectedmosquitoes.

Explain how this information can be used to reduce the spread of malaria.

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(2)


(e) Tobacco mosaic virus (TMV) affects many species of plant.

Figure 3 shows a leaf infected with TMV.

Figure 3

© Nigel Cattlin/Getty Images

TMV destroys chloroplasts in the leaf.

Explain how this could affect the growth of the plant.

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(3)

(Total 14 marks)


Plants absorb light to photosynthesise.

(a) What is the correct word equation for photosynthesis?

Tick one box.

carbon dioxide + glucose oxygen + water

glucose + oxygen carbon dioxide + water

oxygen + water carbon dioxide + glucose

water + carbon dioxide oxygen + glucose

(1)

4


(b) Figure 1 shows some of the apparatus that can be used to measure the rate ofphotosynthesis.

Figure 1

The rate of photosynthesis in the pondweed is affected by different colours of light.

Describe a method you could use to investigate this.

You should include:

• what you would measure

• variables you would control.

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(6)


(c) A scientist carried out a similar investigation.

Her results are shown in Figure 2.

Figure 2

The scientist said:

‘Light stops being a limiting factor at a light intensity of 20 units.’

Give evidence from Figure 2 to support this statement.

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(1)

(d) What could be limiting the rate of photosynthesis at a light intensity of 25 units?

Give one factor.

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(1)

(Total 9 marks)


A student investigated the effect of pond organisms on the amount of carbon dioxide in theirsurroundings.

The student set up six boiling tubes as shown in the figure below.

They were left for 2 days.

Each boiling tube contained pond water with an indicator.

The indicator was pink at the start of the investigation.

• If the amount of carbon dioxide in the water increased the indicator turned yellow.

• If the amount of carbon dioxide in the water decreased the indicator turned purple.

(a) What is the purpose of boiling tube A?

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(2)

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(b) In which boiling tube would the indicator be the most yellow after 2 days?

Explain your answer.

Boiling tube ______________

Explanation _________________________________________________________

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(3)


(c) The colour of the indicator in boiling tube C had not changed after 2 days.

Suggest why.

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(1)

(Total 6 marks)

Plants need nitrate ions in order to make proteins.

A plant is growing in soil flooded with water.

Explain why the plant cannot absorb enough nitrate ions.

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(Total 5 marks)

6


Students used quadrats to estimate the population of dandelion plants on a field.

(a) Describe how quadrats should be used to estimate the number of dandelion plants in afield.

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(4)

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(b) The field measured 40 m by 145 m.

The students used 0.25 m2 quadrats.

The students found a mean of 0.42 dandelions per quadrat.

Estimate the population of dandelions on the field.

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Estimated population of dandelions = ______________

(2)


(c) In one area of the field there is a lot of grass growing in the same area as dandelions.

Suggest why the dandelions may not grow well in this area.

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(4)

(Total 10 marks)

The UK contains large areas of peat bogs that have been present for thousands of years.

(a) Peat is removed from peat bogs.

The peat can be mixed with air and added to garden compost.

The release of carbon dioxide from peat is a problem.

Give two other reasons why gardeners should use less peat-based compost in the future.

1. _________________________________________________________________

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2. _________________________________________________________________

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(2)

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(b) Explain why mixing peat with air leads to the release of carbon dioxide.

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(4)

(Total 6 marks)

A student investigates the rate of respiration in maggots.

Figure 1 shows the equipment he uses.

Figure 1

(a) Why does the student put the maggots on gauze?

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(1)

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(b) When maggots respire they take in a gas from the air and release a different gas.

Solution A absorbs the gas released.

At the start of the investigation the student records the distance of the water droplet fromthe bend in the capillary tube.

Explain what happens to the water droplet as the maggots respire.

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(4)


(c) The table below shows the results the student calculated.

Temperature in °CRate of respiration

in units

5 2.2

10 3.5

20 7.5

30 8.4

40 14.0

The student uses his results to plot the graph in Figure 2.

Label the x and y axis.

Figure 2

(1)

(d) How could the student find out if the result at 30 °C is anomalous?

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(1)


(e) Suggest what the value at 30 °C should be to fit the pattern of the graph.

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(1)

(Total 8 marks)

A student investigated the effect of light intensity on the rate of photosynthesis in pondweed.

(a) The formula for glucose is C6H12O6

Use the formula for glucose to write the balanced symbol equation for photosynthesis.

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(2)

10


(b) Figure 1 shows the apparatus the student used.

Figure 1

The student altered the distance of the lamp from the pondweed and counted the numberof bubbles produced in 30 seconds for each distance.

The table below shows the student’s results.

Distance in cm Number of bubblesproduced in 30

seconds

10 27

20 23

30 16

40 7

50 2

Use the data in the table above to complete the graph on Figure 2.

Figure 2

(3)


(c) The student concluded that the rate of photosynthesis is inversely proportional to thedistance of the lamp from the pondweed.

Does the student’s data support this conclusion?

Use data from Figure 2 to justify your answer.

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(3)

(d) The volume of one bubble can be calculated using the equation:

V = 4 / 3 π r3

The radius of one bubble is 0.1 cm.

The value for π is 3.14

Use data from the table above and the information above to calculate the rate of gasproduction at a distance of 40 cm.

Give your answer in standard form to three significant figures.

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Rate of reaction = __________________ cm3 per minute

(5)

(Total 13 marks)


Photosynthesis needs light.

(a) Complete the balanced symbol equation for photosynthesis.

light6CO2 + _______________________ _______________________ + 6O2

(2)

11

(b) A green chemical indicator shows changes in the concentration of carbon dioxide (CO2) ina solution.

The indicator solution is green when the concentration of CO2 is normal.

The indicator solution turns yellow when the concentration of CO2 is high.

The indicator solution turns blue when the concentration of CO2 is very low or when thereis no CO2.

The indicator solution does not harm aquatic organisms.

Students investigated the balance of respiration and photosynthesis using an aquatic snailand some pondweed.

The students set up four tubes, A, B, C and D, as shown in the table below.

The colour change in each tube, after 24 hours in the light, is recorded.

Tube A Tube B Tube C Tube D

Indicator solutiononly

Indicator solution+ pondweed

Indicator solution+ snail

Indicator solution+ pondweed

+ snail

Stays green Turns blue Turns yellow Stays green

(i) What is the purpose of Tube A?

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(1)


(ii) Explain why the indicator solution in Tube C turns yellow.

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(2)

(iii) Predict the result for Tube D if it had been placed in the dark for 24 hours andnot in the light.

Explain your prediction.

Prediction _____________________________________________________

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Explanation ____________________________________________________

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(3)

(Total 8 marks)


A student ran on a treadmill for 5 minutes.

The speed of the treadmill was set at 12 km per hour.

The graph below shows the effect of the run on the student’s heart rate.

(a) (i) What was the student’s heart rate at rest?

_______________ beats per minute

(1)

(ii) After the end of the run, how long did it take for the student’s heart rate to returnto the resting heart rate?

_______________ minutes

(1)

12


(b) During the run, the student’s muscles needed larger amounts of some substances thanthey needed at rest.

(i) Which two of the following substances were needed in larger amounts duringthe run?

Tick ( ) two boxes.

carbon dioxide

glucose

lactic acid

oxygen

protein

(2)

(ii) Why are the two substances you chose in part (b)(i) needed in larger amountsduring the run?

Tick ( ) one box.

To help make more muscle fibres

To release more energy

To help the muscles to cool down

(1)


(c) After exercise, a fit person recovers faster than an unfit person.

Let the student’s heart rate at the end of exercise = a.

Let the student’s heart rate after 2 minutes of recovery = b.

The table below shows how the difference between a and b, (a − b), is related to aperson’s level of fitness.

(a − b) Level of fitness

< 22 Unfit

22 to 52 Normal fitness

53 to 58 Fit

59 to 65 Very fit

> 65 Top athlete

What is the student’s level of fitness?

Use information from the graph and the table.

a = _______________ beats per minute

b = _______________ beats per minute

(a − b) = _______________ beats per minute

Level of fitness = __________________________________

(3)


(d) The student repeated the run with the treadmill set at 16 km per hour.

The student’s heart rate took 3 minutes longer to return to the normal resting rate thanwhen running at 12 km per hour.

Give reasons why it took longer to recover after running faster.

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(4)

(Total 12 marks)


The diagram below shows the parts of the body that digest and absorb food.

It also shows some details about the structure of the stomach.

(a) Complete the table to show whether each structure is an organ, an organ system or atissue.

For each structure, tick ( ) one box.

Structure OrganOrgansystem

Tissue

Stomach

Cells lining the stomach

Mouth, oesophagus, stomach, liver,pancreas, small and large intestine

(2)

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(b) (i) The blood going to the stomach has a high concentration of oxygen.The cells lining the stomach have a low concentration of oxygen.

Complete the following sentence.

Oxygen moves from the blood to the cells lining the stomach by

the process of ___________________________________ .

(1)


(ii) What other substance must move from the blood to the cells lining the stomach sothat respiration can take place?

Draw a ring around the correct answer.

glucose protein starch

(1)

(iii) In which part of a cell does aerobic respiration take place?

Draw a ring around the correct answer.

cell membrane mitochondria nucleus

(1)

(Total 5 marks)

Photosynthesis uses carbon dioxide to make glucose.

(a) (i) Complete the equation for photosynthesis.

carbon dioxide + _____________ glucose + _____________

(2)

(ii) What type of energy does a plant use in photosynthesis?

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(1)

(iii) Which part of a plant cell absorbs the energy needed for photosynthesis?

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(1)

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(b) The graph shows the effect of the concentration of carbon dioxide on the rate ofphotosynthesis in tomato plants at 20 °C.


(i) What is the maximum rate of photosynthesis of the tomato plants shown in thegraph?

_____________ arbitrary units

(1)

(ii) At point X, carbon dioxide is not a limiting factor of photosynthesis.

Suggest one factor that is limiting the rate of photosynthesis at point X.

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(1)

(c) A farmer plans to grow tomatoes in a large greenhouse.

The concentration of carbon dioxide in the atmosphere is 0.04%.The farmer adds carbon dioxide to the greenhouse so that its concentration is 0.08%.

(i) Why does the farmer use 0.08% carbon dioxide?

Tick ( ) one box.

To increase the rate of growth of the tomato plants

To increase the rate of respiration of the tomatoplants

To increase water uptake by the tomato plants

(1)


(ii) Why does the farmer not use a concentration of carbon dioxide higher than 0.08%?

Tick ( ) two boxes.

Because it would cost more money than using 0.08%

Because it would decrease the temperature of the greenhouse

Because it would not increase the rate of photosynthesis of thetomato plants any further

Because it would increase water loss from the tomato plants

(2)

(Total 9 marks)


During exercise, the heart beats faster and with greater force.

The ‘heart rate’ is the number of times the heart beats each minute.The volume of blood thattravels out of the heart each time the heart beats is called the ‘stroke volume’.

In an investigation, Person 1 and Person 2 ran as fast as they could for 1 minute. Scientistsmeasured the heart rates and stroke volumes of Person 1 and Person 2 at rest, during theexercise and after the exercise.

The graph below shows the scientists’ results.

(a) The ‘cardiac output’ is the volume of blood sent from the heart to the muscles each minute.

Cardiac output = Heart rate × Stroke volume

At the end of the exercise, Person 1’s cardiac output = 160 × 77 = 12 320 cm 3 per minute.

Use information from Figure above to complete the following calculation of Person 2’scardiac output at the end of the exercise.

At the end of the exercise:

Person 2’s heart rate = _______________ beats per minute

Person 2’s stroke volume = _______________ cm 3

Person 2’s cardiac output = _______________ cm 3 per minute

(3)

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(b) Person 2 had a much lower cardiac output than Person 1.

(i) Use information from Figure above to suggest the main reason for the lower cardiacoutput of Person 2.

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(1)

(ii) Person 1 was able to run much faster than Person 2.

Use information from Figure above and your own knowledge to explain why.

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(5)

(Total 9 marks)

Green plants can make glucose.

(a) Plants need energy to make glucose.

How do plants get this energy?

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(2)

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(b) Plants can use the glucose they have made to supply them with energy.

Give four other ways in which plants use the glucose they have made.

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(4)

(Total 6 marks)

Freshwater streams may have different levels of pollution. The level of pollution affects whichspecies of invertebrate will live in the water.

Table 1 shows the biomass of different invertebrate species found in two different streams, X andY.

Table 1

Biomass in g

Invertebrate species Stream X Stream Y

Mayfly nymph 4 0

Caddis fly larva 30 0

Freshwater shrimp 70 5

Water louse 34 10

Bloodworm 10 45

Sludge worm 2 90

Total 150 150

17


(a) The bar chart below shows the biomass of invertebrate species found in Stream X.

(i) Complete the bar chart by drawing the bars for water louse, bloodworm and sludgeworm in Stream Y.

Use the data in Table 1.

Species present

(2)

(ii) Table 2 shows which invertebrates can live in different levels of water pollution.

Table 2

Pollution level Invertebrate species likely to be present

Clean water Mayfly nymph

Low pollution Caddis fly larva, Freshwater shrimp

Medium pollution Water louse, Bloodworm

High pollution Sludge worm


Which stream, X or Y, is more polluted?Use the information from Table 1 and Table 2 to justify your answer.

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(2)

(b) There is a sewage works near another stream, Z.

An accident caused sewage to overflow into Stream Z.Two weeks later scientists took samples of water and invertebrates from the stream.They took samples at different distances downstream from where the sewage overflowed.The scientists plotted the results shown in Graphs P and Q.

Graph P: change in water quality downstream of sewage overflow


Graph Q: change in invertebrates found downstream of sewage overflow

(i) Describe the patterns shown in Graph P.

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(4)

(ii) Describe the relationship between dissolved oxygen and the survival of mayflynymphs in Stream Z. Suggest a reason for the pattern you have described.

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(3)


(c) Many microorganisms are present in the sewage overflow.

Explain why microorganisms cause the level of oxygen in the water to decrease.

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(2)

(Total 13 marks)

(a) Complete the equation for photosynthesis. Draw a ring around each correct answer.

hydrogen alcohol

Carbon dioxide + nitrogenlight energy

glucose + oxygen

water methane

(2)

18

Some students investigated the effect of light intensity on the rate of photosynthesis inpondweed.

The diagram shows the apparatus the students used.


The closer the lamp is to the pondweed, the more light the pondweed receives.

The students placed the lamp at different distances, d, from the pondweed.

They counted the number of bubbles of gas released from the pondweed in 1 minute foreach distance.

(b) A thermometer was placed in the glass beaker.

Why was it important to use a thermometer in this investigation?

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(3)

(c) The students counted the bubbles four times at each distance and calculated the correctmean value of their results.

The table shows the students’ results.

Distanced in cm

Number of bubbles per minute

1 2 3 4 Mean

10 52 52 54 54 53

20 49 51 48 52 50

30 32 30 27 31 30

40 30 10 9 11

(i) Calculate the mean number of bubbles released per minute when the lamp was 40cm from the pondweed.

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Mean number of bubbles at 40 cm = ______________________

(2)


(ii) On the graph paper below, draw a graph to show the students’ results:

• add a label to the vertical axis• plot the mean values of the number of bubbles• draw a line of best fit.

Distance d in cm

(4)

(iii) One student concluded that the rate of photosynthesis was inversely proportional tothe distance of the lamp from the plant.

Does the data support this conclusion?


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(2)


(d) Light intensity, temperature and concentration of carbon dioxide are factors that affect therate of photosynthesis.

Scientists investigated the effects of these three factors on the rate of photosynthesis intomato plants growing in a greenhouse.

The graph below shows the scientists’ results.

Light intensity in lux


A farmer in the UK wants to grow tomatoes commercially in a greenhouse.

The farmer read about the scientists’ investigation.

During the growing season for tomatoes in the UK, natural daylight has an intensity higherthan 30 000 lux.

The farmer therefore decided to use the following conditions in his greenhouse during theday:

• 20°C

• 0.1% CO 2

• no extra lighting.

Suggest why the farmer decided to use these conditions for growing the tomatoes.

You should use information from the scientists’ graph in your answer.

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(4)

(Total 17 marks)


The diagram below shows a single-celled alga which lives in fresh water.

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(a) Which part of the cell labelled above:

(i) traps light for photosynthesis

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(1)

(ii) is made of cellulose?

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(1)

(b) In the freshwater environment water enters the algal cell.

(i) What is the name of the process by which water moves into cells?

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(1)

(ii) Give the reason why the algal cell does not burst.

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(1)

(c) (i) The alga can photosynthesise.

Complete the word equation for photosynthesis.

water + _______________ _______________ + oxygen

(2)


(ii) The flagellum helps the cell to move through water. Scientists think that the flagellumand the light-sensitive spot work together to increase photosynthesis.

Suggest how this might happen.

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(2)

(d) Multicellular organisms often have complex structures, such as lungs, for gas exchange.

Explain why single-celled organisms, like algae, do not need complex structures for gasexchange.

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(3)

(Total 11 marks)

(a) A student carried out the following investigation using a plant with variegated leaves. Avariegated leaf has green and white stripes.

The student:

• left the plant in the dark for 3 days to remove the starch

• fixed two pieces of card to a leaf on the plant

• left the plant in the light for 2 days

• removed the leaf from the plant

• tested the leaf for starch.

Figure 1 shows how the two pieces of card were attached to the leaf.

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Figure 1

Leaf without card Leaf with card


Figure 2 shows the same leaf after 2 days in the light.The leaf has been tested for starch.

Figure 2

Give two conclusions from this investigation.

Tick ( ) two boxes.

Carbon dioxide is needed for photosynthesis.

Chlorophyll is needed for photosynthesis.

Light is needed for photosynthesis.

Water is needed for photosynthesis.

(2)


(b) Scientists investigated the effect of light intensity on the rate of photosynthesis.

Figure 3 shows the scientists’ results.

Figure 3

Light intensity in arbitrary units

Describe the effect of increasing light intensity on the rate of photosynthesis.You should include numbers from Figure 3 in your description.

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(3)

(c) At a light intensity of 250 arbitrary units, light is not a limiting factor of photosynthesis.

(i) What is the evidence for this in Figure 3?

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(1)

(ii) Give two factors that could be limiting the rate of photosynthesis at a light intensity of250 arbitrary units.

1. ____________________________________________________________

2. ____________________________________________________________

(2)

(Total 8 marks)


Figure 1 shows an athlete running on a treadmill.

Figure 1

© Starush/istock/Thinkstock

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After running for several minutes, the athlete’s leg muscles began to ache.This ache was caused by a high concentration of lactic acid in the muscles.

(a) The equation shows how lactic acid is made.

glucose lactic acid (+ energy)

Name the process that makes lactic acid in the athlete’s muscles.

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(1)


(b) Scientists investigated the production of lactic acid by an athlete running at differentspeeds.

In the investigation:

• the athlete ran on the treadmill at 4 km per hour

• the scientists measured the concentration of lactic acid in the athlete’s blood after 2minutes of running.

The investigation was repeated for different running speeds.

Figure 2 shows the scientists’ results.

Figure 2

Treadmill speed in km per hour

(i) How much more lactic acid was there in the athlete’s blood when he ran at 14 km perhour than when he ran at 8 km per hour?

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Answer = _____________ mmol per dm3

(2)


(ii) Why is more lactic acid made in the muscles when running at 14 km per hour thanwhen running at 8 km per hour?

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(3)

(Total 6 marks)

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

Deforestation affects the environment.

Deforestation is causing a change in the amounts of different gases in the atmosphere. Thischange causes global warming and climate change.

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The image below shows an area of deforestation.

© Nivellen77/iStock/Thinkstock


Give the reasons why deforestation is taking place.

Describe how deforestation is causing the change in the amounts of different gases in theatmosphere.

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Extra space _____________________________________________________________

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_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

(Total 6 marks)


Scientists investigated how exercise affects blood flow to different organs in the body.

The scientists made measurements of blood flow to different organs of:

• a person resting in a room at 20°C

• the same person, in the same room, doing vigorous exercise at constant speed on anexercise cycle.

The table shows the scientists’ results.

OrganBlood flow in cm3 per minute whilst …

restingdoing vigorous

exercise

Brain 750 750

Heart 250 1000

Muscles 1200 22 000

Skin 500 600

Other 3100 650

(a) In this investigation, it was better to do the exercise indoors on an exercise cycle than to gocycling outdoors on the road.

Suggest two reasons why.

Do not include safety reasons.

1. _________________________________________________________________

___________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

23

(b) Blood flow to one organ did not change between resting and vigorous exercise.

Which organ? ________________________________________________

(1)


(c) (i) How much more blood flowed to the muscles during vigorous exercise than whenresting?

______________________________________________________________

______________________________________________________________

Answer = _________________ cm3 per minute

(2)

(ii) Name two substances needed in larger amounts by the muscles during vigorousexercise than when resting.

1. ____________________________________________________________

2. ____________________________________________________________

(2)

(iii) Tick ( ) one box to complete the sentence.

The substances you named in part (c)(ii) helped the muscles to

make more lactic acid.

respire aerobically.

make more glycogen.

(1)


(iv) The higher rate of blood flow to the muscles during exercise removed larger amountsof waste products made by the muscles.

Which two substances need to be removed from the muscles in larger amountsduring vigorous exercise?

Tick ( ) two boxes.

Amino acids

Carbon dioxide

Glycogen

Lactic acid

(2)

(d) The total blood flow was much higher during exercise than when resting.

One way to increase the total blood flow is for the heart to pump out a larger volume ofblood each beat.

Give one other way to increase the blood flow.

___________________________________________________________________

___________________________________________________________________

(1)

(Total 11 marks)


Some students investigated the effect of light intensity on the rate of photosynthesis.

They used the apparatus shown in Diagram 1.

Diagram 1

The students:

• placed the lamp 10 cm from the pondweed

• counted the number of bubbles of gas released from the pondweed in 1 minute

• repeated this for different distances between the lamp and the pondweed.

(a) The lamp gives out heat as well as light.

What could the students do to make sure that heat from the lamp did not affect the rate ofphotosynthesis?

___________________________________________________________________

___________________________________________________________________

(1)

24


(b) The table shows the students’ results.

Distance in cm

Number of bubblesper minute

10 84

15 84

20 76

40 52

50 26

(i) At distances between 15 cm and 50 cm, light was a limiting factor for photosynthesis.

What evidence is there for this in the table?

______________________________________________________________

______________________________________________________________

(1)

(ii) Give one factor that could have limited the rate of photosynthesis when the distancewas between 10 cm and 15 cm.

______________________________________________________________

(1)


(c) In this question you will be assessed on using good English, organising information clearlyand using specialist terms where appropriate.

Diagram 2 shows a section through a plant leaf.

Diagram 2

Describe the structure of the leaf and the functions of the tissues in the leaf.

You should use the names of the tissues in your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(6)

(Total 9 marks)


Some students studied bluebell plants growing in two different habitats.

Habitat A was a sunny field next to woodland.Habitat B was a shady, moist woodland.

A bluebell plant can have several flowers on one flower stalk. The students counted the numberof flowers on each of 40 bluebell flower stalks growing in each habitat.The bar charts show the results.

Habitat A: Sunny field next to woodland

Number of flowers per stalk

Habitat B: Shady, moist woodland

Number of flowers per stalk

(a) The students wanted to collect valid data.Describe how the students should have sampled the bluebell plants at each habitat tocollect valid data.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

25


(b) (i) The students used the bar charts to find the mode for the number of flowers per stalkin the two habitats.

The mode for the number of flowers per stalk in habitat A was 11.

What was the mode for the number of flowers per stalk in habitat B?

Mode = _________________________

(1)

(ii) The students suggested the following hypothesis:

‘The difference in the modes is due to the plants receiving different amounts ofsunlight.’

Suggest why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(iii) Suggest how the students could test their hypothesis for the two habitats.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(c) Suggest how receiving more sunlight could result in the plants producing more flowers perstalk.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 9 marks)


The diagrams show four types of cell, A, B, C and D.Two of the cells are plant cells and two are animal cells.

(a) (i) Which two of the cells are plant cells?

Tick ( ) one box.

A and B

A and D

C and D

(1)

26

(ii) Give one reason for your answer.

______________________________________________________________

______________________________________________________________

(1)


(b) (i) Which cell, A, B, C or D, is adapted for swimming?

(1)

(ii) Which cell, A, B, C or D, can produce glucose by photosynthesis?

(1)

(c) Cells A, B, C and D all use oxygen.

For what process do cells use oxygen?

Draw a ring around one answer.

osmosis photosynthesis respiration

(1)

(Total 5 marks)

This question is about photosynthesis.

(a) Plants make glucose during photosynthesis. Some of the glucose is changed into insolublestarch.

What happens to this starch?

Tick ( ) one box.

The starch is converted into oxygen.

The starch is stored for use later.

The starch is used to make the leaf green.

(1)

27


(b) A student investigated the effect of temperature on the rate of photosynthesis in pondweed.

The diagram shows the way the experiment was set up.

(i) The student needed to control some variables to make the investigation fair.

State two variables the student needed to control in this investigation.

1. ____________________________________________________________

2. ____________________________________________________________

(2)

(ii) The bubbles of gas are only produced while photosynthesis is taking place.

What two measurements would the student make to calculate the rate ofphotosynthesis?

1. ____________________________________________________________

2. ____________________________________________________________

(2)


(c) The graph shows the effect of temperature on the rate of photosynthesis in the pondweed.

Temperature in °C

(i) Name the factor that limits the rate of photosynthesis between the points labelled Aand B on the graph.

______________________________________________________________

(1)

(ii) Suggest which factor, carbon dioxide, oxygen or water, might limit the rate ofphotosynthesis between the points labelled C and D on the graph.

______________________________________________________________

(1)

(Total 7 marks)


The mould Penicillium can be grown in a fermenter. Penicillium produces the antibioticpenicillin.

The graph shows changes that occurred in a fermenter during the production ofpenicillin.

Time in hours

(a) During which time period was penicillin produced most quickly?


0 – 20 hours 40 – 60 hours 80 – 100 hours

(1)

28

(b) (i) Describe how the concentration of glucose in the fermenter changes between 0 and30 hours.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)


(ii) How does the change in the concentration of oxygen in the fermenter compare withthe change in concentration of glucose between 0 and 30 hours?

Tick ( ) two boxes.

The oxygen concentration changes after the glucose concentration.

The oxygen concentration changes before the glucose concentration.

The oxygen concentration changes less than the glucose concentration.

The oxygen concentration changes more than the glucose concentration.

(2)

(iii) What is the name of the process that uses glucose?


distillation filtration respiration

(1)

(Total 6 marks)


The heart pumps the blood around the body. This causes blood to leave the heart athigh pressure.

The graph shows blood pressure measurements for a person at rest.The blood pressure was measured in an artery and in a vein.

Time in seconds

(a) Which blood vessel, A or B, is the artery?

Blood vessel ________

Give two reasons for your answer.

Reason 1 ___________________________________________________________

___________________________________________________________________

Reason 2 ___________________________________________________________

___________________________________________________________________

(2)

29


(b) Use information from the graph to answer these questions.

(i) How many times did the heart beat in 15 seconds? ___________

(1)

(ii) Use your answer from part (b)(i) to calculate the person’s heart rate per minute.

______________________________________________________________

______________________________________________________________

Heart rate = __________ beats per minute

(1)

(c) During exercise, the heart rate increases.

The increased heart rate supplies useful substances to the muscles at a faster rate.

Name two useful substances that must be supplied to the muscles at a faster rateduring exercise.

1. _________________________________________________________________

2. _________________________________________________________________

(2)

(Total 6 marks)

(a) Complete the word equation for photosynthesis.

carbon dioxide + waterenergy

glucose + ______

(1)

30

(b) Draw a ring around the correct answer to complete each sentence.

(i) The energy needed for photosynthesis comes from

light.

osmosis.

respiration.

(1)

(ii) Energy is absorbed by a green pigment called

chloride.

chloroplast.

chlorophyll.

(1)


(iii) If the temperature is decreased the rate of photosynthesis will

decrease.

increase.

stay the same.

(1)

(c) Give three ways in which plants use the glucose made in photosynthesis.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________

3. _________________________________________________________________

___________________________________________________________________

(3)

(Total 7 marks)

Infections by antibiotic resistant bacteria cause many deaths.

The bar chart below shows information about the number of deaths per year in England fromMethicillin-resistant Staphylococcus aureus (MRSA) and from Clostridium difficile (C.difficile)over 4 years.

Year

31


(a) (i) Describe the trend for deaths caused by C.difficile.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(ii) Suggest a reason for the trend you have described in part (a)(i).


______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(iii) Calculate the percentage change in deaths caused by MRSA from 2009 to 2010.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Percentage change in deaths caused by MRSA = _______________ %

(2)

(iv) Numbers have not yet been published for 2011.

When the numbers are published, scientists do not expect to see such a largepercentage change from 2010 to 2011 as the one you have calculated for 2009 to2010.

Suggest one reason why.

______________________________________________________________

______________________________________________________________

(1)


(b) Before 2007 there was a rapid increase in the number of deaths caused by MRSA.

Describe how the overuse of the antibiotic methicillin led to this increase.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

(Total 10 marks)

One factor that may affect body mass is metabolic rate.

(a) (i) What is meant by metabolic rate ?

______________________________________________________________

______________________________________________________________

(1)

32

(ii) Metabolic rate is affected by the amount of activity a person does.

Give two other factors that may affect a person’s metabolic rate.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)


(b) Predicted early death is the number of years that a person will die before the mean age ofdeath for the whole population. The predicted early death of a person is affected by theirbody mass.

Scientists have calculated the effect of body mass on predicted early death.

The graph shows the results of the scientists’ calculations.

Ideal body mass

The number of times above or below ideal body mass is given by the equation:

In the UK the mean age of death for women is 82.

A woman has a body mass of 70 kg. The woman’s ideal body mass is 56 kg.

(i) Use the information from the graph to predict the age of this woman when she dies.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Age at death = ___________ years

(2)


(ii) The woman could live longer by changing her lifestyle.

Give two changes she should make.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)

(Total 7 marks)

(a) Use words from the box to complete the equation for aerobic respiration.

alcohol glucose lactic acid water

______________ + oxygen carbon dioxide + ______________ (+ energy)

(2)

33


(b) Some students investigated the effect of temperature on the rate of aerobic respiration inearthworms.

The diagram shows the apparatus the students used.When the tap is closed, the bead of liquid moves to the left as the earthworms take inoxygen.

The students put the test tube into a water bath at 20°C for 10 minutes.They left the tap open during this time.

Why did the students put the test tube in the water bath at 20°C for 10 minutes?

Tick ( ) one box.

Because the air contains more oxygen at 20°C.

Because the air contains less carbon dioxide at 20°C.

So the earthworms’ body temperature would change to 20°C.

(1)


(c) The students then:

• closed the tap

• started a stopwatch

• recorded the position of the bead of liquid every 2 minutes for 10 minutes

• repeated the experiment at 10°C.

The graph shows the students’ results.

Time in minutes

(i) How much oxygen did the earthworms take in during the 10 minutes at 20°C?

Use information from the graph to work out your answer.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Volume of oxygen taken in = ___________________ mm3

(2)


(ii) The earthworms took in this volume of oxygen in 10 minutes.

Use your answer from part (c)(i) to calculate how much oxygen the earthworms tookin each minute.

______________________________________________________________

______________________________________________________________

Volume of oxygen taken in = _______________________ mm3 per minute

(1)

(iii) The earthworms took in less oxygen each minute at 10°C than they took in at 20°C.

Explain why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(d) When drawing the line on the graph for the experiment at 10°C, the students ignored thereading at 8 minutes.

(i) Suggest why they ignored the reading at 8 minutes.

______________________________________________________________

______________________________________________________________

(1)

(ii) One student suggested they should repeat the experiment twice more at eachtemperature.

How would repeating the experiment improve the investigation?

______________________________________________________________

______________________________________________________________

(1)

(Total 10 marks)


The diagram shows a section through a plant leaf.

(a) Use words from the box to name two tissues in the leaf that transport substances aroundthe plant.

epidermis mesophyll phloem xylem

______________________________ and ______________________________

(1)

34

(b) Gases diffuse between the leaf and the surrounding air.

(i) What is diffusion?

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(ii) Name one gas that will diffuse from point A to point B on the diagram on a sunny day.

______________________________________________________________

(1)

(Total 4 marks)


(a) Complete the equation for photosynthesis.

______________ + water ______________ + ______________

(3)

35

(b) The rate of photosynthesis in a plant depends on several factors in the environment.These factors include light intensity and the availability of water.

Describe and explain the effects of two other factors that affect the rate of photosynthesis.

You may include one or more sketch graphs in your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(5)

(Total 8 marks)


Mark schemes

(a)

an extra line from a LH box negates that mark2

1

(b) any one from:

• not enough oxygen present (for aerobic respiration)• more energy required for exercise (than can be transferred by aerobic respiration)

1

allow named example for exercise

(c) produces carbon dioxide1

produces ethanol1

plus any two from:

• (carbon dioxide) makes bread rise• (carbon dioxide) makes beer / cider / (some) wines fizzy

allow for alcoholic drinks / named drink• (ethanol) is the alcohol in beer / cider / wine / spirits

2

[7]

(a) 66 (beats per minute)12

(b) heart rate increased1

(c) 41


(d) any two from:

• resting heart rate was lower• heart rate did not increase as much• heart rate did not increase as fast• heart rate returned to normal sooner

2

(e) Level 2 (3–4 marks):A detailed and coherent explanation is given, which logically links changes in the bodyduring exercise to reasons for these changes.

Level 1 (1–2 marks):Discrete relevant points made. Links may not be made.

0 marks:No relevant content

Indicative content

Changes:• breathing rate increases• deeper breathing• (body) temperature increases• sweating occurs• muscle fatigue• vasodilation

Explanations linked to correct change:• to provide more oxygen• to remove carbon dioxide faster• (as) more energy required• (so) increased respiration• (so) more energy transferred• for movement or contraction of muscles• some energy warms the body• (sweating) cools the body down• (by) evaporation of sweat

4

[9]


(a)

3

3

(b) (trachea) has mucus1

to trap pathogens1

(trachea) has cilia1

to move mucus out of trachea1

(c) dependent variable:number of times mosquitoes landed on socks

1

control variable:any one from:

• number of mosquitoes in each container• length of time socks worn• dampness of socks• same type of socks• size of container• time• temperature• species of mosquito• age of mosquito

1

(d) use worn socksoruse chemical from worn socks

1

to attract / trap infected mosquitoes1


or accept:

wear clean socks / change socks regularly (1)

to reduce the chance of attracting mosquitoes (1)

(e) less chlorophyll present1

(so) less light absorbed1

(so) reduced photosynthesisor(so) less sugar / food made

1

[14]

(a) water + carbon dioxide oxygen + glucose

extra box ticked negates mark1

4

(b) Level 3 (5–6 marks):A coherent method is described with relevant detail, which demonstrates a broadunderstanding of the relevant techniques and procedures. The steps in the method arelogically ordered. The method would lead to the production of valid results.

Level 2 (3–4 marks):The bulk of the method is described with mostly relevant detail, which demonstrates areasonable understanding of the relevant scientific techniques and procedures. Themethod may not be in a completely logical order and may be missing some detail.

Level 1 (1–2 marks):Simple statements are made which demonstrate some understanding of some of therelevant scientific techniques and procedures. The response may lack a logical structureand would not lead to the production of valid results.


Indicative content• description of how the apparatus would be used• reference to control intensity of light / brightness• use of ruler to measure distance of light from beaker / pondweed• reference to varying colour of light or use of different filters• plant releases gas / oxygen• measure number of bubbles / volume of gas produced• same length of time• reference to control of temperature• reference to control / supply of carbon dioxide in water• do repeats and calculate a mean

6

(c) rate does not increase further if light intensity increased beyond 20

allow graph levels off after 201


(d) any one from:

• temperature• carbon dioxide (concentration)• amount of chlorophyll

allow number of chloroplasts1

[9]

(a) control15

to check that the indicator colour does not change on its ownorto check any changes in colour are due to the organisms

1

(b) (tube) E1

most carbon dioxide1

(due to) only respiration occurring

allow no carbon dioxide used for photosynthesis

allow 1 mark max if chose tube D and give a correct reason1

(c) the amount of carbon dioxide produced by respiration equalled amount absorbed forphotosynthesis

1

[6]

(nitrate) ions are absorbed by active transport16

(active transport) is the movement of ions against the concentration gradient

allow (active transport) is the movement of ions from a dilute to amore concentrated solution

1

(active transport) requires energy from respiration1

(respiration) requires oxygen1

no / little oxygen / air in water-logged soil1

[5]

(a) (placed) randomly

allow description of placement1

7


sufficient number (of quadrats) used1

count (dandelions) in each quadrat1

use mean number of dandelions, area of quadrat and area of field to estimate population

accept (area of field / area quadrat) × mean number of dandelionsper quadrat

1

(b) (40 × 145) / 0.25 = 23 2001

(0.42 × 23 200 =) 9744

allow 9744 with no working shown for 2 marks

allow ecf from correct attempt at the previous step) × 0.42 for 1mark

1

(c) Level 2 (3–4 marks):A detailed and coherent explanation is given. Logical links between clearly identifiedrelevant points are made to explain why dandelion growth may be limited.

Level 1 (1–2 marks):Discrete relevant points are made. The logic may be unclear.


Indicative content

factors that may be considered:competition for resources including:• light• water• space• mineral ions (allow nutrients / salts / ions from the soil)

reference to why growth may be limited:• (light) energy for photosynthesis• water as a raw material for photosynthesis / support• surface area exposed to light• sugar / glucose produced in photosynthesis• (space) to grow bigger• (space) for growth of root system• (mineral ions) for growth• (mineral ions / sugar) for production of larger molecules or named example

4

[10]

(a) reduces biodiversity18


peat is being used faster than it forms

allow peat is non-renewable1

(b) decay / decomposition / rotting of peat1

by microorganisms / bacteria / microbes / fungi / decomposers introduced when peat ismixed with air

1

that respire using substances in peat as reactant1

and using oxygen that is introduced when peat is mixed with air1

[6]

(a) (to) stop them falling in the solution

or

to stop them drowning (in the solution)1

9

(b) Level 2 (3–4 marks):A detailed and coherent explanation is given of how the droplet moves, clearly andlogically linked to the process of respiration.

Level 1 (1–2 marks):Simple statements are made about movement of the water droplet, but any attempts atexplaining the reason or linking the movement to the process of respiration are unclearand poorly structured.


Indicative content• water droplet moves towards the maggots / boiling tube

Explanation:• the oxygen in the boiling tube is used up in respiration• (and) the carbon dioxide released from respiration is absorbed by solution A• which causes a pressure difference• so air is drawn into the tube• bringing the water droplet with it.

4

(c) x axis: Temperature in °C

both needed for the mark

y axis: Rate of respiration in units1


(d) repeat the experiment at 30 °C1

(e) 10.5

allow range 10.4–10.81

[8]

(a) 6CO2 + 6H2O C6H12O6 + 6O2

correct reactants1

correct products1

(b) correct scale and label on x axis1

all 5 plots correct

tolerance ±½ small square

allow 2 or 3 plots correct for 1 mark2

(c) no

no mark

although as distance increases, rate decreases1

the line curves or line should be straight1

suitable data quoted

examples:

• supports conclusion between 20–40 (cm)

• does not support conclusion between 10–20 (cm)1

10


(d) volume of 1 bubble = 4 / 3 × 3.14 × (0.1)3

1

= 0.004191

at 40 cm there are 7 bubbles1

vol at 40 cm = 0.02933

allow ecf from incorrect value taken from table1

Rate per minute = × 2

= 5.86 × 10−2 (cm3 per min)

allow 5.86 × 10−2 with no working shown for 5 marks1

answer not given in standard form or to incorrect number of sig. figsmax 4 marks

[13]

(a) 6H2O

in the correct order1

C6H12O61

11


(b) (i) control

do not accept ‘control variable’

allow:

to show the effect of the organisms

or

to allow comparison

or

to show the indicator doesn’t change on its own1

(ii) snail respires1

releases CO21

(iii) turns yellow1

plant can't photosynthesise so CO2 not used up1

but the snail (and plant) still respires so CO2 produced1

[8]

(a) (i) 501

(ii) 4

accept 3.9 − 4.01

12

(b) (i) glucose1

oxygen1

(ii) to release more energy1


(c) correct readings from graph:

a = 120

b = 60

allow 60 - 611

calculation correct for candidate’s figures:

e.g. a − b = 601

level of fitness correct for candidate’s figures:

e.g. very fit1

(d) any four from:• higher heart rate (at 16 km / h) (so takes longer to slow to normal)• more energy needed• not enough O 2 supplied / more O2 needed / reference to O2-debt• (more) anaerobic respiration• (more) lactic acid made / to be broken down / to remove / to oxidise• higher blood flow needed to deliver (the required amount of) oxygen.

‘more’ must be given at least once for full marks

do not allow more energy produced

allow higher blood flow to remove lactic acid / remove (additional)CO2

4

[12]

(a)

Structure OrganOrgansystem

Tissue

Stomach

Cells lining the stomach

Mouth, oesophagus,stomach, liver,pancreas, small andlarge intestine

all 3 correct = 2 marks2 correct = 1 mark1 or 0 correct = 0 marks

2

13

(b) (i) diffusion

allow phonetic spelling1


(ii) glucose1

(iii) mitochondria1

[5]

(a) (i) LHS = water

accept H2O

do not accept H2O / H2O1

RHS = oxygen

accept O2

do not accept O / O2 / O21

(ii) light / sunlight

ignore solar / sun / sunshine

do not allow thermal / heat1

(iii) chloroplasts

allow chlorophyll1

14

(b) (i) 201

(ii) any one from:• light (intensity)• temperature.

1

(c) (i) To increase the rate of growth of the tomato plants1

(ii) Because it would cost more money than using 0.08%1

Because it would not increase the rate of photosynthesis of the tomato plantsany further

1

[9]


(a) 5624

allow 2 marks for:

• correct HR = 148 and correct SV = 38 plus wrong answer / noanswer

or

• only one value correct and ecf for answer

allow 1 mark for:

• incorrect values and ecf for answer

or

• only one value correct3

15

(b) (i) Person 2 has low(er) stroke volume / SV / described

eg Person 2 pumps out smaller volume each beat

do not allow Person 2 has lower heart rate1

(ii) Person 1 sends more blood (to muscles / body / lungs)1

(which) supplies (more) oxygen1

(and) supplies (more) glucose1

(faster rate of) respiration or transfers (more) energy for use

ignore aerobic / anaerobic

allow (more) energy release

allow aerobic respiration transfers / releases more energy (thananaerobic)

do not allow makes (more) energy1

removes (more) CO2 / lactic acid / heat

allow less oxygen debt

or less lactic acid madeor (more) muscle contraction / less muscle fatigue

if no other mark awarded,

allow person 1 is fitter (than person 2) for max 1 mark1

[9]

(a) light is trapped / absorbed / used

extra answers cancel mark

ignore solar / sunshine1

16


by chlorophyll / chloroplasts

if no other marks awarded, allow 1 mark for photosynthesis /equation for photosynthesis

1

(b) (to make) starch (for storage)

ignore ‘for growth’ unqualified

ignore respiration1

(to make) fat / oil (for storage)1

(to make) amino acids / proteins / enzymes1

(to make) cellulose / cell walls

allow for active transport

allow any other correct, named organic substances (eg DNA / ATP /chlorophyll / hormone)

if no named examples, allow ‘to make named cell structures’ formax. 1 mark

1

[6]

(a) (i) correct bar heights

three correct 2 marks

two correct 1 mark

one or none correct 0 marks

ignore width2

17

(ii) (Stream Y)

has many sludge worms / bloodworms

or

has no mayflies / caddis or few shrimp

allow 1 mark if invertebrate not named but correct association given1

which indicate medium or high pollution1


(b) (i) suspended solids increase (as a result of sewage overflow)1

then decrease downstream / return to original levels1

oxygen levels decrease (after sewage overflow)1

and then rise again1

(ii) any three from:

• mayflies decrease (to zero) near overflow

accept ‘have died out’• because oxygen is low or mayflies have high oxygen demand• mayflies repopulate / increase as oxygen increases again• can’t be sure if dissolved oxygen or suspended solids is the cause

3

(c) they respire / respiration

aerobic respiration gains 2 marks1

this requires / uses up the oxygen1

[13]

(a) LHS = water1

RHS = glucose1

18

(b) any three from:

• (measure) temperature

ignore reference to fair test• to check that the temperature isn’t changing• rate of reaction changes with temperature• temperature is a variable that needs to be controlled

allow lamp gives out heat3

(c) (i) 10

correct answer = 2 marks

allow 1 mark for:

allow 1 mark for correct calculation without removal of anomalousresult ie 15

2


(ii) graph:

allow ecf from (c)(i)

label on y-axis as ‘number of bubbles per minute’1

three points correct = 1 mark

allow ± 1 mm

four points correct = 2 marks2

line of best fit = smooth curve1

(iii) as distance increases, rate decreases – pro

allow yes between 20 – 401

but should be a straight line / but line curves – con / not quite pro

allow not between 10 – 20

if line of best fit is straight line, allow idea of poor fit1

(d) any four from:

• make more profit / cost effective• raising temp. to 25 °C makes very little difference at 0.03% CO 2

• (at 20 °C) with CO 2 at 0.1%, raises rate• (at 20 °C with CO 2 at 0.1%) → >3x rate / rises from 5 to 17• although 25 °C → higher rate, cost of heating not economical• extra light does not increase rate / already max. rate with daylight

accept ref to profits c.f. costs must be favourable4

[17]

(a) (i) chloroplast119

(ii) cell wall1

(b) (i) osmosis

accept diffusion1

(ii) cell wall (prevents bursting)1

(c) (i) carbon dioxide

allow correct formula1


glucose

allow sugar / starch1

(ii) any two from:

• light sensitive spot detects light• tells flagellum to move towards light• more light = more photosynthesis

2

(d) (cell has) larger SA:volume ratio1

short (diffusion) distance

allow correct description1

(diffusion) via cell membrane is sufficient / good enough

or

flow of water maintains concentration gradient1

[11]

(a) chlorophyll is needed for photosynthesis120

light is needed for photosynthesis1

(b) increases1

levels off / reaches a maximum / remains constant / stays the same / plateaus

do not allow stops / stationary / peaks

allow stops increasing1

goes up to / reaches a maximum / levels off at (a rate of) 200 (arbitrary units)orlevels off at 225 – 240 (light units)

ignore references to other numerical values1

(c) (i) higher light intensity does not increase rate of photosynthesis

accept the graph stays level (above this value)

allow stops increasing

allow the rate of photosynthesis stays the same (above this value)1


(ii) any two from:

• carbon dioxide (concentration)• temperature / heat• (amount of) chlorophyll / chloroplasts

allow water

allow ions / nutrients

ignore ref to surface area of the leaf2

[8]

(a) anaerobic respiration

allow phonetic spelling1

21

(b) (i) 4.4

4.2, 4.3, 4.5 or 4.6 with figures in tolerance (6.7 to 6.9 and 2.3 to2.5) and correct working gains 2 marks

4.2, 4.3, 4.5 or 4.6 with no working shown or correct working withone reading out of tolerance gains 1 mark

correct readings from graph in the ranges of 6.7 to 6.9 and 2.3 to2.5 but no answer / wrong answer gains 1 mark

2

(ii) more energy is needed / used / released

do not allow energy production

(at 14 km per hour)

ignore work1

not enough oxygen (can be taken in / can be supplied to muscles)

allow reference to oxygen debt

do not allow less / no oxygen1

so more anaerobic respiration (to supply the extra energy) or more glucosechanged to lactic acid

allow not enough aerobic respiration1

[6]

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.

0 marksNo relevant content

22


Level 1 (1 – 2 marks)There is at least one reason for deforestationoran attempt at a description of at least one way deforestation is affecting the atmosphere.

Level 2 (3 – 4 marks)There is at least one reason for deforestationanda description of the way deforestation is affecting one gas in the atmosphereorthe process that causes an effect.

Level 3 (5 – 6 marks)There are reasons for deforestationanda clear description of the way deforestation is affecting one gas in the atmosphereandthe process that causes this.

examples of the points made in the response

Reasons for deforestation

• timber for construction / furniture / boat building / paper production• growing plants for biofuels for motor fuel / aviation / lawnmowers• use of wood as a fuel• land for building or agriculture to provide food, such as rice fields and cattle ranching

Effects of deforestation

• increase in carbon dioxide in atmospheredue to burningdue to activities of microbesless carbon dioxide taken in / locked up (by trees)less photosynthesis

• increase in methane in atmospheredue to rice production / cattle

extra information

ignore references to oxygen

accept explanations of the effect of water (vapour)

[6]


(a) any two from:

or allow converse for outdoors

• constant speed

• variable speed

• constant effort

• variable terrain

• constant temperature

• traffic conditions

• variable temperature

• wind (resistance)

• rain / snow

allow weather

allow pollution only if qualified by effect on body function but ignorepollution unqualified

if no other marks obtained allow variable conditions outdoors2

23

(b) Brain1

(c) (i) 20 800

correct answer with or without working gains 2 marks

if answer incorrect, allow 1 mark for use of 1200 and 22 000 only2

(ii) oxygen

apply list principle1

do not accept other named substances eg CO2 water

glucose / sugar

allow glycogen

ignore food / carbohydrate1

(iii) respire aerobically1

(iv) carbon dioxide1

lactic acid1


(d) increased heart rate

ignore adrenaline / drugs

accept heart beats more but not heart pumps more1

[11]

(a) any one from:

ignore ‘check temperature’

• add a water bath

• heat screen

• use LED

• low energy bulb / described1

24

(b) (i) rate / number of bubbles decreases

accept converse with reference to increasing light or shorterdistance

or

less oxygen / gas released

ignore reference to rate of photosynthesis1

(ii) temperature / CO2 (concentration)

accept ‘it was too cool’ or not enough CO2

accept number of chloroplasts / amount of chlorophyll

allow heat

allow CO2

do not allow CO2

1

(c) Marks awarded for this answer will be determined by the Quality of WrittenCommunication (QWC) as well as the standard of the scientific response. Examinersshould also refer to the information in the Marking guidance, and apply a ‘best-fit’approach to the marking.

0 marksNo relevant content.

Level 1 (1-2 marks)There is a brief description of at least 1 tissue or at least 1 function of an indicatedpart of the leaf.

The account lacks clarity or detail.


Level 2 (3-4 marks)There is a clear description which includes at least 1 named tissue and at least 1correct function described for an indicated part of the leaf.

Level 3 (5-6 marks)There is a detailed description of most of the structures and their functions.

Examples of responses:

• epidermis

• cover the plant

• mesophyll / palisade

• photosynthesises

• phloem

• xylem

• transport.

The following points are all acceptable but beyond the scope of thespecification:

• (waxy) cuticle – reduce water loss

• epidermis – no chloroplasts so allows light to penetrate

• stomata / guard cells – allow CO 2 in (and O2 out) or controls water loss

• palisade (mesophyll) – many chloroplasts to trap light

– near top of leaf for receiving more light

• spongy (mesophyll) – air spaces for rapid movement of gases6

[9]

(a) use of quadrat / point frame

allow description1

25

randomly placed / random sampling

ignore reference to transects1

(b) (i) 61

(ii) more light in A / in field / where sunny

ignore sun1


more / better / faster photosynthesis in A / with more light

allow converse1

(iii) use light meter / measure light intensity in both habitats1

take many measurements at same time of the day1

or

laboratory / field investigation with 2 batches high light and low light (1)

count or number of flowers in each (1)

counting point is dependent on investigation point

(c) more glucose / energy available

allow other named product eg protein

allow if more energy produced1

for growth

dependent on 1st mark1

[9]

(a) (i) C and D

no mark if more than one box is ticked1

26

(ii) any one from:

do not allow if other cell parts are given in a list

• (have) cell wall(s)

• (have) vacuole(s)1

(b) (i) A


(ii) D


(c) respiration


[5]


(a) The starch is stored for use later

no mark if more than one box is ticked1

27

(b) (i) any two from:

do not accept temperature

apply list principle

ignore reference to time

• carbon dioxide (concentration)

• light intensity• light colour / wavelength

allow 1 mark for light if neither intensity or colour are awarded

• pH

• size / amount of pondweed / plant

• same / species / type pondweed

• amount of water in the tube

ignore amount of water alone2

(ii) number / amount of bubbles or amount of gas / oxygen

allow volume of bubbles (together)

ignore ‘the bubbles’ unqualified1

(relevant reference to) time / named time interval

allow how long it bubbles for

do not accept time bubbles start / stop

ignore speed / rate of bubbling

ignore instruments

do not accept other factors eg temperature

accept how many bubbles per minute for 2 marks1

(c) (i) temperature

allow heat / cold / °C1

(ii) carbon dioxide / CO2

allow CO2

do not accept CO2

1

[7]

(a) 40 – 60 hours128


(b) (i) decrease1

1st slowly then faster / appropriate detail from the graph – e.g. from 7.8 to 0 /faster after 4 – 10h

1

(ii) oxygen after glucose

extra box ticked cancels 1 mark1

oxygen less than glucose1

(iii) respiration1

[6]

(a) A

no mark - can be specified in reason part

if B given - no marks throughout

if unspecified + 2 good reasons = 1 mark

high(er) pressure in A

allow opposite for B

do not accept ‘zero pressure’ for B

pulse / described in A

accept fluctuates / ‘changes’

allow reference to beats / beating

ignore reference to artery pumping2

29

(b) (i) 171

(ii) 68

accept correct answer from student’s (b)(i) × 41

(c) oxygen / oxygenated blood

allow adrenaline

ignore air

glucose / sugar

extra wrong answer cancels - eg sucrose / starch / glycogen /glucagon / water

allow fructose

ignore energy

ignore food2

[6]


(a) oxygen

allow O2 / O2

do not accept O2 or O1

30

(b) (i) light1

(ii) chlorophyll1

(iii) decrease1

(c) any three from:

• for respiration / energy

do not accept use energy for photosynthesis• to make cellulose / starch

accept named carbohydrate other than glucose• to make lipid / fat / oil

accept fatty acid / glycerol• to make protein

accept named protein / amino acid / named amino acid• to build big molecules from small molecules / metabolism

if no other marks awarded for making molecules allow 1 mark forgrowth / repair / new cells

3

[7]

(a) (i) decrease1

rate of decrease slows1

31

(ii) any one from:• more use of disinfectant

allow any reasonable increase in hygiene or sterilisationprecautions

• more use of hand washing• more careful / more often cleaning of patient facilities• raised awareness / education about hygiene

1

Explanation:stops / reduces the bacteria being transferred / spreading

1


(iii) 800 – 500 / 800 × 100 =1

37.5 (%)

correct answer with or without working gains 2 marks1

(iv) any one from:

• numbers quite low now so hard to reduce further• was a big campaign / much publicity (in 2009) so more people already doing it• hygiene / cleaning now good so hard to improve• hospitals short of money so less staff to clean

1

(b) mutation occurred giving resistance (to methicillin)

do not accept overuse caused mutation1

resistant bacteria not able to be treated / not killed1

these bacteria multiplied / reproduced / spread quickly1

[10]

(a) (i) rate of chemical reactions (in the body)132

(ii) any two from:

• heredity / inheritance / genetics

• proportion of muscle to fat or (body) mass

allow (body) weight / BMI

• age / growth rate

• gender

accept hormone balance or environmental temperature

ignore exercise / activity2

(b) (i) 77

correct answer with or without working gains 2 marks

allow 1 mark for 70 / 56 or 1.25 or 52

(ii) increase exercise

accept a way of increasing exercise1


reduce food intake

accept examples such as eat less fat / sugar

allow go on a diet or take in fewer calories

ignore lose weight

ignore medical treatments such as gastric band / liposuction1

[7]

(a) LHS – glucose133

RHS – water

allow H2O / H201

(b) so the earthworms’ body temperature would change to 20°C1

(c) (i) 56 or 55 or 54

if incorrect answer given accept 60 - 5 for 1 mark

or 60 – 6 for 1 mark

or 60 – 4 for 1 mark2

(ii) one-tenth of answer to (c)(i) eg 5.51

(at 10°C / lower temperature):

lower rate of respiration

allow chemical reactions slower or enzymes less active

ignore breathing

do not allow anaerobic1

worms less active / worms release less energy / worms use less energy1

(d) (i) anomalous result / not in line with other data / does not fit the pattern1

(ii) more representative / more reliable / can check ‘repeatability’ / see if get similarvalues / identify anomalies

ignore valid / more fair

ignore reproducible

ignore ‘to remove’ anomalies

do not accept more accurate or more precise1

[10]


(a) xylem and phloem

either order

allow words ringed in box

allow mis-spelling if unambiguous1

34

(b) (i) movement / spreading out of particles / molecules / ions / atoms

ignore names of substances / ‘gases’1

from high to low concentration

accept down concentration gradient

ignore ‘along’ / ‘across’ gradient

ignore ‘with’ gradient1

(ii) oxygen / water (vapour)

allow O2 / O2

ignore O2/ O

allow H2O / H2O

ignore H2O1

[4]

(a) LHS – carbon dioxide / CO2

allow CO2

ignore CO2

1

35

RHS

in either order

glucose / carbohydrate / sugar

allow starch

allow C6H12O6 / C6H12O6

ignore C6H12O6

1

oxygen

allow O2 / O2

ignore O2 / O1


(b) any five from:

• factor 1: CO 2 (concentration)

• effect - as CO 2 increases so does rate and then it levels off or shown in a graph

• explanation:(graph increases) because CO2 is the raw material or used in photosynthesis /converted to organic substance / named egor(graph levels off) when another factor limits the rate.

accept points made via an annotated / labelled graph

• factor 2: temperature

allow warmth / heat

• effect – as temperature increases, so does the rate and then it decreases orshown in a graph

allow ‘it peaks’ for description of both phases

• explanation:(rise in temp) increases rate of chemical reactions / more kinetic energy

allow molecules move faster / more collisions

or(decreases) because the enzyme is denatured.

context must be clear = high temperature

allow other factor plus effect plus explanation:

eg light wavelength / colour / pigments / chlorophyll / pH / minerals /ions / nutrients / size of leaves

2nd or 3rd mark can be gained from correct description andexplanation

5

[8]


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