level 7 biology questions - moulsham high school 7 biology questions.pdf · moulsham high school 1...

Moulsham High School 1

Level 7 Biology Questions

1. The graph below shows how a population of fish in a lake changed over a period of time.

(a) In which time interval, A, B, C, D or E, did the population of fish increase most quickly?

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How can you tell this from the graph?

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1 mark

(b) Which part of the graph shows when the fish began to compete with each other for food? Give the letter.

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1 mark

(c) What does part D of the graph show about the birth rate and the death rate of the fish?

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1 mark


(d) Part E of the graph shows a population crash when all the fish died.

Suggest two reasons why a population might crash in this way.

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

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1 mark

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

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1 mark

maximum 5 marks

2. Andy investigated the digestion of a protein called gelatin. He used an enzyme called pepsin from the human stomach, and three cubes of gelatin each 1 cm3. He set up the experiment shown below and put the test-tubes in a water-bath at 37°C. He measured the time for the digestion of the gelatin.

(a) Why did Andy choose a temperature of 37°C for t he water-bath?

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1 mark


(b) In test-tube C, the cube of gelatin that had been cut into pieces was digested

more quickly than the whole cube in test-tube A.

Give the reason for this.

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1 mark

(c) The boiled pepsin in test-tube B did not digest the gelatin.

Why did boiling this enzyme stop it working?

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1 mark

(d) Protein is needed for growth and repair. The digestion of protein begins in the stomach and is completed in the small intestine.

(i) What are the products of the digestion of protein? Tick the correct box.

amino acids energy

sugars vitamins

1 mark

(ii) Why is it necessary to digest protein before it can be used for growth and repair?

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1 mark

maximum 5 marks

3. The table shows how hydrogencarbonate indicator solution changes colour when the concentration of carbon dioxide in it changes.

concentration of carbon dioxide colour change

increases orange to yellow

decreases orange to purple


Sunil set up the experiment shown below and put both test-tubes on a window-

sill.

Use information in the table to help you answer the questions below.

(a) The indicator in test-tube A changed from orange to yellow.

(i) What process, in the cells of the maggots, caused this colour change?

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1 mark

(ii) Explain what happens in this process to cause the colour change.

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1 mark

(b) The indicator in test-tube B changed from orange to purple.

(i) What process, in the cells of the leaves, caused this colour change?

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1 mark

(ii) Explain what happens in this process to cause the colour change.

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1 mark


(c) Sunil then put two fresh leaves into test-tube C containing 30 cm3 of orange

hydrogencarbonate indicator. He added some maggots on a piece of wire mesh as shown below. He put the test-tube on a window-sill.

The indicator remained orange. Explain why.

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1 mark

maximum 5 marks

4. Read the magazine cutting about research into heart disease.

More heart disease in older women. Heart disease amongst British women in the 60-79 age group is more common than previous research suggested. A recent study of 4,286 British women in that age group indicated that one in five showed signs of heart disease.


(a) Why can the results of this research not be used to draw any conclusions about

heart disease amongst women across the world?

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1 mark

(b) Give one reason why the data collected in this study is likely to be reliable.

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1 mark

(c) After reading the magazine cutting, pupils wrote the ideas below.

Decide if each idea is supported by information in the cutting. Tick the correct box.

Use the information in the cutting as evidence to justify your decision in the third column.

Idea Is the idea supported by

evidence? Tick the correct box.

Use the information in the magazine cutting as evidence

to justify your decision

One in five of all British females show signs of heart disease.

Yes

No

Earlier treatment for heart disease must have been more effective than modern medicines.

Yes

No

Four out of five British women in the 60-79 age group showed no signs of heart disease.

Yes

No

3 marks

maximum 5 marks


5. Scientists measured the concentration of the insecticide, DDT, in three animals and a

microscopic plant called chlamydomonas.

(a) The food chain for these four organisms is shown below.

not to scale

(i) In the space below, draw the pyramid of numbers for this food chain. Write the name of the correct organism next to each section of the pyramid.

1 mark


(ii) The bar chart shows the concentration of DDT in the four organisms.

1600

1400

1200

1000

800

600

400

200

0

concentrationof DDT

(parts per million)

chlamydomonas daphnia fish heron

Give one reason for the difference in the concentration of DDT in these organisms.

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1 mark

(b) In 1970 the average concentration of DDT in the tissues of sea lions in California was 760 parts per million. Nearly half the sea lion pups born in that year died because of high levels of DDT in their tissues.

How does DDT get from the body of a mother sea lion into the body of her pup:

(i) before the pup is born?

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1 mark


(ii) after the pup is born?

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1 mark

maximum 4 marks

6. Joanne measured the volume of air she breathed in and out of her lungs. She used the machine shown in the photograph below.

The graphs represent the volume of air Joanne breathed in and out with each breath before and during exercise.

2000

1000

0

2000

1000

00 05 510 10

time (seconds) time (seconds)

before exercise during exercise

volume ofair breathed(cm )3

key

air in air out

(a) During exercise Joanne breathed more air in and out of her lungs than before exercising.

(i) How much more air did Joanne breathe in with each breath during exercise?

.................... cm3

1 mark (ii) Explain fully why Joanne needed to breathe in more air during exercise.


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3 marks

(b) (i) As Joanne exercised, the volume of air she breathed in and out increased. Give one other way Joanne’s breathing changed during exercise.

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1 mark

(ii) How does the graph show this other change?

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1 mark

maximum 6 marks


7.

‘Wilting roses are a thing of the past.’

Scientists at the University of Leeds have found a way to modify the genes of flowering plants. They claim that flowers from modified plants remain fresh in a vase of water for up to six months longer than flowers from unmodified plants.

Plan an investigation you could carry out in the school laboratory to test the claim that flowers from modified plants last for much longer than flowers from unmodified plants.

You will be provided with flowers from modified plants and from unmodified plants.


In your plan give:

• the one factor you will change as you carry out your investigation; (This is the independent variable.)

• the factor you will measure; (This is the dependent variable.)

• one of the factors you should control to ensure a fair test; • the time scale for the investigation.

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maximum 4 marks


8. The drawings show Sofia taking part in four different sports.

The table below shows the average energy needed for each sport for one hour.

sport average energy need for one hour (kJ)

bowling 1030

tennis 1760

football 2260

running 3700

(a) (i) Sofia plays football for two hours each week. She also goes bowling for two hours each week. Explain why Sofia uses up her food reserves more quickly when playing football than when bowling.

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1 mark


(ii) Athletes should not drink alcohol before taking part in sport.

Give two effects of alcohol which would affect an athlete’s performance.

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

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1 mark

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

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1 mark

(b) Some athletes take glucose tablets before a 100 metre race. They can also obtain glucose from starch in their diet. A starch molecule is made up of many glucose molecules joined together as shown below.

part of a molecule of starch

In the digestive system, starch is broken down into glucose:

molecules of glucose

An athlete can obtain energy more quickly by eating glucose rather than starch. Explain why.

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1 mark

maximum 4 marks

9. Cholera is a disease caused by bacteria. These bacteria produce a poison. The poison prevents the large intestine from absorbing water from the food passing through it. People with cholera can lose more than a litre of water per hour.

(a) Give one function of water in the body.

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1 mark


(b) People can be injected with a vaccine against cholera. The vaccine contains a

tiny amount of the cholera poison and not the cholera bacteria. As a result, people become immune to cholera.

Describe how vaccination makes a person immune to cholera.

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2 marks

(c) The cholera poison makes the skin permeable. A new method of vaccinating against cholera is to put a small amount of the poison, mixed with other vaccines, on a plaster. The plaster is left on the skin for a day. The vaccines pass through the skin and the person becomes immune to cholera and to other diseases.

(i) Why should only a tiny amount of the poison be used?

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1 mark

(ii) Suggest one advantage of vaccinating people in this way.

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1 mark

Maximum 5 marks

10. The quagga is an extinct animal that lived in Africa. Quaggas belonged to the same group as zebras. The drawings below show a zebra and a quagga.


(a) Zebras and quaggas used to breed with each other. The offspring contained a

combination of both zebra and quagga genes (genetic information). How were zebra and quagga genes passed on from the parents to their offspring?

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1 mark

(b) These days there are some zebras that still show some quagga features. Scientists are using zebras to try to produce quaggas by selective breeding. Describe the steps in this selective breeding process.

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3 marks

Maximum 4 marks

11. The drawing shows a bluebell plant. The plant grows from an underground stem called a bulb. Each year new leaves and flowers grow from the bulb.


(a) Describe the process by which glucose is made in the leaves.

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3 marks

(b) Many plants make starch from glucose. What group of nutrients do both glucose and starch belong to?

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1 mark

(c) In the sixteenth century bluebell bulbs were dug up to obtain a starch-like substance that was used to make collars stiff.

(i) Digging up bluebell bulbs has caused a decrease in the number of bluebells growing in Britain. It is now against the law to dig up bluebells.

Suggest one other environmental reason why the number of bluebell plants has decreased in Britain.

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1 mark


(ii) Every 10 years the trees and bushes in some bluebell woods are cut down

to ground level.

What effect does this have on the number of bluebells in the woods? Explain your answer.

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1 mark

Maximum 6 marks

12. A group of pupils recorded some different characteristics of pupils in their class.


The table below shows their results.

name gender height, in cm

mass, in kg

hand span, in cm

arm span, in cm

eye colour

Julie girl 152 48 17.2 160 blue

Laura girl 157 54 15.0 141 green

Aftab boy 159 49 18.4 172 brown

Jenna girl 144 46 17.4 161 hazel

Barry boy 148 49 17.4 162 blue

Oliver boy 172 57 21.5 204 brown

Safina girl 155 48 16.8 158 brown

Maria girl 154 50 17.9 166 green

Amanat girl 162 46 16.2 150 brown

Thomas boy 157 49 19.9 186 blue

(a) Oliver concluded that boys do not have green eyes.

Explain why his conclusion is not justified.

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1 mark

(b) Name two continuous variables in their table.

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

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

1 mark


(c) Look at the scatter graphs below.

210

200

190

180

170

160

150

140

22

21

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16

15

14

220

210

200

190

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140

210

200

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140140

140

15 16 17 18 19 20 21 22150

150

160

160

170

170

180

180

height, in cm

height, in cm mass, in kg

hand span, in cm

graph A

graph C graph D

graph B

armspan,in cm

handspan,in cm

armspan,in cm

armspan,in cm

× × × ×

××

×

××

× ××××

×

×

××

×

×

× × ××

×

×

×

××

×

×

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×

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××

×

×

46 48 50 52 54 56 58 60

Use the data in the scatter graphs to show whether each of the conclusions below is true, false or you cannot tell.

conclusions true or false or cannot tell

Graph C shows that the shortest pupil has the smallest hand span. ........................................

Graph B shows the strongest correlation between two variables. ........................................

Graph A looks similar to graph C because of the high correlation of arm span to hand span. ........................................

Boys are generally taller than girls. ........................................

2 marks

Maximum 4 marks


13. Almost 200 years ago, an important investigation into plant growth was carried out.

George Sinclair, the Duke of Bedford’s head gardener, planted seeds in 242 plots of land, each four feet square.

Charles Darwin concluded from this investigation:

If a plot of ground is sown with one species of grass and a similar plot is sown with several different species of grass, the second plot will produce a greater number of plants and a greater mass of plant material.

(a) Give one feature of the plots that was controlled in Sinclair’s investigation.

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1 mark

(b) Why did Sinclair use many plots rather than just two?

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1 mark

(c) What two factors are named in Darwin’s conclusion as the measurable outcomes in the investigation? (These are the dependent variables.)

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

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

1 mark

(d) Which one factor was changed in Sinclair’s investigation? (This is called the independent variable.)

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1 mark

(e) The soil in each plot was tested.

Suggest one reason why these soil tests were helpful to the interpretation of the results of the investigation.

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1 mark


(f) Give one reason why several different species of grass in a plot produced a

greater mass of plant material than a single species in a plot.

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1 mark

maximum 6 marks

level 7 biology questions - moulsham high school 7 biology questions.pdf · moulsham high school 1...

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