- ks3 8a nutrition and digestion ... · web viewinto beaker c, she put 50 cm3 pepsin solution and a...

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KS3 8A Nutrition and digestion 69marksQ1. The table shows the amounts of energy used in running and in walking at different

speeds by people of different body masses.

ActivityEnergy used in kilojoules per hour

34 kgperson

50 kgperson

70 kgperson

90 kgperson

Running, 9 km per hour 1530 1850 2770 3700Running, 11 km per hour 2140 2560 3860 5120Running, 16 km per hour 2980 3570 5380 7140Walking, 3 km per hour 530 670 1010 1340Walking, 5 km per hour 740 880 1340 1760Walking, 7 km per hour 1030 1240 1850 2480

(a) Describe two patterns you can see in the data.1 .....................................................................................................................................................................................................................................................................2 .....................................................................................................................................................................................................................................................................

(2)Q4. The drawing shows part of an organ system.

(a) Which organ system is it part of?Tick the correct box.

circulatory system reproductive system

digestive system respiratory system

1 mark (b) Where is this part of the organ system found in the body?

Tick one box.

1 markQ5. The information below shows the recommended daily amounts of nutrients and

energy for four different people.

Information taken from Report 41 of the Department of Health - DietaryReference Values for Food Energy and Nutrients for the United Kingdom 1991.

(a) Suggest one reason why the bricklayer needs a higher energy diet than the computer operator.

………………………..................................................................................................................... [1 mark] (b) Explain why the 15-year-olds need more calcium than the adults.

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

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

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

(d) A balanced diet contains a variety of foods which provide nutrients and energy. The drawings show four different foods. Choose from these to answer the questions

which follow.

Which of these foods is the best source of:fibre? ...........................................

calcium? ...........................................protein? ...........................................

3 marksQ6. (a) Egg white contains a protein called albumen. A pupil carried out an experiment to investigate the digestion of three identical

cubes of cooked egg white using the enzyme pepsin. She set up the experiment as follows.

Into beaker A, she put 50 cm3 pepsin solution and a cube of egg white left whole.

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Into beaker B, she put 50 cm3 pepsin solution and a cube of egg white which had been cut into eight small cubes.

Into beaker C, she put 50 cm3 pepsin solution and a cube of egg white which had been cut into sixty four tiny cubes.

She added 1 cm3 hydrochloric acid to each beaker and placed the three beakers in a waterbath at 37°C. The table gives the pupil’s observations five hours later.

(i) Why was the cube of egg white which had been cut into sixty four pieces digested most quickly?

………………………..................................................................................................................... [1 mark] (ii) When protein is digested it is broken down into smaller molecules.

What name is given to these smaller molecules?

………………………..................................................................................................................... [1 mark] (b) In another experiment, it was found that pepsin does not digest sucrose

(sugar). Explain why sucrose is not digested by pepsin.

………………………..................................................................................................................... [1 mark] (c) The graph below shows how quickly pepsin digests meat protein at different

temperatures.

Explain why pepsin does not digest protein at temperatures above 60°C.

………………………..................................................................................................................... [1 mark] (d) Glands in the stomach wall produce mucus, hydrochloric acid and an inactive

form of pepsin called pepsinogen. In the stomach hydrochloric acid reacts with the pepsinogen to produce pepsin.(i) Suggest one other purpose of acid in the stomach.

………………………..................................................................................................................... [1 mark] (ii) Suggest one reason why pepsin is secreted in its inactive form.

………………………..................................................................................................................... [1 mark] (iii) Suggest one purpose of mucus produced in the wall of the stomach.

………………………..................................................................................................................... [1 mark] (iv) Bile from the liver makes the duodenum alkaline. Give one reason why the

contents of the duodenum need to be alkaline.

………………………..................................................................................................................... [1 mark]



Q7. Some people have unbalanced diets. This can give them problems with their health.(a) Draw one line from each unbalanced diet to the health problem it can cause.

[4marks]

(b) Explain why eating a lot of chips every day is bad for your health.

………………………..................................................................................................................... [1 mark] The information below was taken from the label of a can of baked beans in

tomato sauce.

(a) A healthy diet contains a number of groups of substances. The nutritional information lists some of these.

Give one group of substances, needed for a healthy diet, which is missing from the nutritional information.

………………………..................................................................................................................... [1 mark]

(b) (i) Which food, shown in the list of ingredients, provides the most protein in this

………………………..................................................................................................................... [1 mark]

(ii) Give one reason why we need protein in our diet.

………………………..................................................................................................................... [1 mark] (c) (i) Name one food, shown in the list of ingredients, which provides fibre.

………………………..................................................................................................................... [1 mark] (ii) Why is fibre needed for a balanced diet?

………………………..................................................................................................................... [1 mark]Q9. A medical researcher used a tube to remove some of the liquid from a person's

stomach. The researcher put the liquid into a flask which had a piece of boiled beef in it. The beef was digested in six hours. The diagrams show the flask at different stages of the experiment.



(a) (i) What type of substance in the liquid from the stomach caused the beef to be digested in six hours?

………………………..................................................................................................................... [1 mark] (ii) The researcher kept the flask at 37°C. Explain why.

………………………..................................................................................................................... [1 mark]

(b) In the human body, the digestion of protein in meat begins in the stomach and is completed in the small intestine.

(i) What is digested protein used for in the body?

………………………..................................................................................................................... [1 mark] (ii) Describe how the products of digestion get from inside the small intestine to

the cells in the rest of the body.

……………………….....................................................................................................................

………………………..................................................................................................................... 2 marks

Q10. Peter burns a piece of crispbread to find out how much energy is stored in it. Energy from the burning crispbread raises the temperature of the water in the test-tube.

(a) Describe one way Peter has arranged the apparatus so that he is working safely.

……………………….....................................................................................................................

………………………..................................................................................................................... 2 marks

(b) Peter wants to find out if potato crisps contain as much energy as crispbread. He does the experiment again using a piece of potato crisp.Suggest two things he must do to make the experiment a fair test.1. .................................................................................................................

2. .................................................................................................................1 mark



The table shows some of the nutritional information from a packet of crispbread and a packet of potato crisps.

(c) Peter burns 1.0 g of potato crisp instead of 1.0 g of crispbread in a similar experiment. What result will he get when he burns the potato crisp? Tick the correct box.

The change in the temperature of the water will be greater.

The change in the temperature of the water will be the same.

The change in the temperature of the water will be smaller.

There will be no change in the temperature of the water. [1] (d) (i) Fibre contains energy. Explain why this energy can not be used by the

human body.

………………………..................................................................................................................... [1 mark] (ii) Use the table in part (b) to give two reasons for choosing crispbread rather

than potato crisps as part of a balanced diet.

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

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

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

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

(e) Crispbread does not contain vitamin C. Which of the foods in the list below is the best source of vitamin C?Tick the correct box.

cheese eggs fish oranges

1 mark

Q11. Sadie and Tom carried out an experiment to investigate the digestion of starch using an enzyme called amylase.



(a) Why was the mixture of enzyme and starch kept in a water bath?

………………………..................................................................................................................... [1 mark] Sadie and Tom placed drops of iodine solution on a white tile. They know that starch will

turn the iodine solution from brown to dark blue. Every 30 seconds they added a drop of the mixture of enzyme and starch to a drop of

iodine solution on the tile. At first the drops turned blue, but after 240 s they stayed brown. (b) Why did the mixture stop turning the drops of iodine solution blue after 240 s?

………………………..................................................................................................................... [1 mark] (c) They then carried out the experiment with the water bath at 35°C. This time, the

drops stopped turning blue after 120 s. How does raising the temperature from 25°C to 35°C affect the digestion of starch?

………………………..................................................................................................................... [1 mark] (d) Sadie and Tom want to compare the experiment at 35°C with the results from the

experiment at 25°C. Describe what they need to do to make this a fair comparison.

………………………..................................................................................................................... [1 mark] (e) A balanced diet includes all of the substances in the following list. Starch fat fibre minerals protein vitamins

(i) Give the names of the two substances in the list which are absorbed into the blood without being digested.

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

2. ..................................................................……1 mark

(ii) Which substance in the list passes through the body without being digested?

………………………..................................................................................................................... [1 mark]

Q12 The following are important parts of a balanced diet.

carbohydratesproteins

fatsvitamins

water A pupil has a sweet, juicy orange to eat.

(a) Complete the following sentences using words from the list above.(i) An orange is a good source of

......................…… and ......................…….2 marks

(ii) An orange is a poor source of

......................…… and ......................…….2 marks

(b) Give the names of two parts of a balanced diet which are not shown in the list above.

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

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

(c) In order to obtain the nutrients, food must be chewed Give two reasons why it is important to chew food.1. ..................................................................................................................

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

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



Q13. The card shows the amounts of fat and fibre in some types of food and drink from a café.

(a) From the card above, choose a meal consisting of a burger, a drink and some potato, to give:(i) the least fat;

1 mark(ii) the most fibre.

1 mark Write your answers in the table below.

Food and drink meal with the least fat meal with the most fibretype of burger

type of drink the drinks do notcontain fibre

type of potato (b) Draw a line from each nutrient to the main reason why it is needed.

Draw only four lines. nutrient main reason why the nutrient is needed

• to keep the intestine working properly

calcium • • for healthy teeth and bones

fibre • • for insulation

protein • • to provide energy

sugar • • for growth and repair4 marks



Q14. New-born mammals produce an enzyme called rennin which clots the protein in milk. New-born mammals can only digest the protein after it clots.(a) Pat investigated how pH affects the time for rennin to clot the protein in milk. She put 2 cm3 of milk into each of four test-tubes, A, B, C and D.

She put these test-tubes and a test-tube of rennin into a water-bath at 35°C. After a few minutes, Pat transferred 4 drops of the rennin into test-tubes

A, B and C. She varied the pH by adding the chemicals shown in the table. To test-tube D she added 2 drops of hydrochloric acid only.

The table below shows the results of Pat’s experiment.

(i) Use the results of test-tubes C and D to state the function of the enzyme in the clotting process.

………………………..................................................................................................................... [1 mark] (ii) Use Pat’s results to explain why rennin clots milk quickly in the stomach.

………………………..................................................................................................................... [1 mark] (iii) Suggest what happens to the activity of rennin as it passes from the stomach

into the small intestine. Explain your answer.

……………………….....................................................................................................................

………………………..................................................................................................................... 2 marks

(b) Pat then investigated how temperature affects the time for rennin to clot milk. She prepared four water-baths, at 0°C, 25°C, 35°C and 60°C.

Into each water-bath she put a test-tube containing 2 cm3 of milk and a test-tube containing rennin plus a chemical to give the correct pH.

In each water-bath, she transferred four drops of the rennin into the test-tube of milk and timed how long it took for the milk to clot. The table shows her results.

temperature ofwater-bath, in °C

time for milk to clot,in seconds

0 no clotting25 2335 1060 no clotting (i) Explain why no clotting occurred in the test-tube at 60°C.

………………………..................................................................................................................... [1 mark] (ii) Pat took the test-tube out of the water-bath at 0°C and put it into the water-

bath at 35°C. The milk clotted.Why was clotting still possible in this test-tube?

………………………..................................................................................................................... [1 mark]



(iii) Raising the temperature from 25°C to 35°C made the milk clot more quickly.How could Pat change her experiment to show more precisely how temperature affects the time it takes for milk to clot?

………………………..................................................................................................................... [1 mark] (c) After rennin clots milk protein, a different enzyme helps to digest the protein. What

are the products of protein digestion?

………………………..................................................................................................................... [1 mark]

Q15. The diagram shows some of the organs of the human body.

(a) Give the names of two labelled parts where food is digested.

.................................................... and ...................................................1 mark

(b) Why do we need to chew our food and mix it with saliva?.....................................................................................................................

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



(c) (i) Draw one line from each bad habit to the organ it harms.

3 marks (ii) Which organ in the list below can be harmed if we eat too much fat?

Tick the correct box.brain heart

lung ribs

………………………..................................................................................................................... MARK SCHEME

M1. (a) increased speedor harder exercise / running→increased need / use / loss of energy

1allow further you run / walk the more energy you need increased mass / bigger → increased use of energy

1 (b) any three from:• supply / using (more / enough) oxygenor get (more) oxygen in blood(*)• remove (more) CO2(*)• doing (more) workorusing (more) energy allow produce energy(*)(*)need reference to ‘more’ ONCE only for full marks• for respiration• prevent build up of lactic acidor prevent oxygen debt

or prevent anaerobic (respiration)or allow aerobic (respiration)

3M2. (a) answers should refer to microvilli and to the larger surface areawhich they provide any one from• folds or projections or microvilli give a large surface areaaccept ‘villi for microvilli’do not accept ‘large area’• folds or projections or microvilli increase rate of absorptiondo not accept ‘increased rate of absorptiondo not accept ‘folds’ or ‘projections’ without qualification

1 (b) starchaccept ‘glycogen’

1 (c) plasma √if more than one box is ticked, award no mark

1



(d) (i) glycogendo not accept ‘starch’

1(ii) they are solubleaccept ‘osmotic effects could damage the liver’or ‘they would affect the osmotic potential of the cells’

1M3. (a) any two from• vitaminsaccept a named vitamin• mineralsaccept ‘mineral salt’ or a named mineral• waterdo not accept ‘fibre’ or ‘roughage’

2 (L5) (b) A if more than one box is ticked, award no mark

1 (L5) (c) D if more than one box is ticked, award no mark

1 (L5) (d) contains more proteinaccept ‘is better balanced’do not accept ‘less carbohydrate’ or ‘less fat’

1 (L6) (e) any one from• coconut contains more fataccept ‘it contains more fat’• potato contains less fat• fat is a richer source of energy than carbohydrateaccept ‘fat contains more energy than carbohydrates’

1 (L6)M4. (a) digestive system if more than one box is ticked, award no mark

1 (L4)(b) lowest box tickedif more than one box is ticked, award no mark

2]M5. (a) answers should show an understanding that the bricklayerdoes physical work more activeaccept ‘uses up more energy’or’ lifts bricks all day’ or ‘does more work’do not accept ‘works harder’ or ‘has a tougher job’or ‘does hard work’

1 (L5) (b) answers should refer to bones and their growth calcium is needed for boneaccept ‘it is needed for teeth’

1 (L5) the 15-year olds are still growingaccept ‘the adults have stopped growing’

1 (L5)

(c) any one from• girls menstruateaccept ‘girls have periods’• to replace blood lost by menstruationdo not accept ‘iron is needed to produce red blood cells’do not accept ‘growth spurts’

1 (L5) (d) carrot

1 (L5) milk

1 (L5) chicken

1 (L5)M6. (a) (i) larger surface areado not accept ‘already partly broken down’

1(ii) any one from• polypeptidesdo not accept ‘monomers’• peptides• amino acidsdo not accept ‘acids’

1 (b) any one from• enzymes are specificaccept ‘enzymes are selective’• enzymes only act on one type of substrate• pepsin only digests proteinsaccept ‘it only digests protein’or ‘pepsin is a protease’• sucrose is not a proteindo not accept ‘it is not a protein’• because of the shape of the moleculesaccept references to lock and key mechanismaccept ‘other enzymes digest the sucrose’do not accept ‘pepsin does not digest sugar’or ‘sucrose is a sugar’ or ‘sucrose doesn’tneed digesting as it goes through the gut wall’

1 (c) enzymes become denatured or destroyed or deactivateddo not accept ‘enzymes are killed’ or ‘it is too hot to react’or ‘by the time it reached 60° the meat was already digested’

1 (d) (i) any one from• kills bacteria or germs or micro-organisms• provides the correct pH for the action of pepsinaccept ‘hydrolysis of protein’

1 (ii) pepsin could digest or damage the cells of the stomachaccept ‘if it were made in its active form it woulddamage the cells or stomach’ accept ‘stops theenzyme working before it is secreted’



1 (iii) protects the stomach wall from the action of pepsin or acidaccept ‘protects the stomach’ or ‘lines the stomach’accept ‘lubricates the path of the food’

1 (iv) any one from• the enzymes in the duodenum work in a alkaline mediumaccept ‘it stops the action of pepsin’• to neutralise acids from the stomach

1

M7. (a)

if more than four lines are drawn deduct one mark for eachincorrectly drawn lineminimum mark zero

4 (L3) (b) they contain too much fataccept ‘they contain fat’ or ‘they make you fat or overweight’accept ‘it is an unbalanced diet’ or ‘it could give you aheart attack’ or it causes heart disease’

1 (L3)M8. (a) any one from• vitaminsaccept a named vitamin eg. vitamin C• mineralsaccept a named mineral eg. Iron or calcium or saltdo not accept ‘water’

1 (L5) (b) (i) haricot beansaccept ‘beans’

1 (L5) (ii) any one from• for growthaccept ‘for muscles or hair or nails’• for repairaccept ‘for healing wounds’• for replacement of cellsaccept making any named protein eg haemoglobin• for making proteinsaccept ‘for making enzymes or antibodies

1 (L5) (c) (i) any one from• haricot beansaccept ‘beans• tomato pureeaccept ‘tomatoes’accept ‘spices or ‘paprika’ or ‘onion powder’

1 (L5) (ii) any one from• it helps the passage of food through the gutaccept ‘it keeps the food moving’• it prevents constipationaccept ‘it helps you go to the toilet’or it makes you feel full’do not accept ‘it helps fill you up’ or ‘it makes you feel full’

1 (L5)M9. (a) (i) an enzymeaccept ‘enzymes’ or ‘pepsin’ or ‘protease’accept ‘acid’ or ‘hydrochloric acid’

1 (L7)(ii) any one from• it is the temperature at which enzymes work best• it is the temperature of the bodydo not accept ‘this is the body heat’ or ‘to make a fair test’

1 (L7) (b) (i) any one from• for growthaccept ‘for new cells’• for repair• for making other protein or enzymesaccept ‘to supply amino acids’do not accept ‘for energy’

1 (L6) (ii) one mark is for the products of digestion getting throughthe barrier between intestine and blood, and the othermark is for the method of transportthey pass through the intestine wallaccept ‘they are absorbed or pass into the blood’or ‘they pass through the gut wall’

1 (L7)they are carried by the blood or plasma or blood streamaccept ‘they go through the blood vesselsor arteries or veins’

1 (L7)M10. (a) any one from• the test-tube is pointing away from himaccept ‘the test-tube is pointing away from the edgeof the bench’ do not accept ‘the test-tube is at an angle’• he used a cork and a pin to hold the



burning crispbreadaccept ‘he used a pin’ or ‘he is not holding the crispbread’or ‘the cork is on the stand’• the test-tube is held in a clampaccept ‘he used a clamp’ or ‘the test-tube is held tightly’• it is away from the edge of the bench• the apparatus is arranged over the base of the stand for stabilityaccept ‘the tube is over the base’do not accept ‘he is wearing goggles

1 (L5)• use the same amount of water• use the same mass or weight of crispaccept ‘use the same mass of food’do not accept ‘use the same amount of food’• the crisp must be the same distance from the test tube as thecrispbread was• start with water at the same temperature• shield both experiments from the draughtdo not accept ‘use the same apparatus’or ‘heat for the same amount of time’

2 (L4) (c) The change in the temperature of the water will be greater. if more than one box is ticked, award no mark

1 (L6) (d) (i) fibre is not digestedaccept ‘it is not absorbed’or ‘it does not get broken down’do not accept ‘it is insoluble’

1 (L6) (ii) any two from• it contains less fataccept ‘it is less fattening’or ‘it contains less energy’• it contains more fibre• it contains more proteindo not accept ‘more carbohydrate’

2 (L6) (e) oranges if more than one box is ticked, award no mark

1 (L5)M11. (a) any one from• to keep the temperature constantaccept ‘to keep them at the correct temperature’do not accept ‘to keep them at body temperature’• so that the experiment was not affected by a change in temperaturein the room• to control the temperature or a variable

1 (b) any one from• the starch had been digested or broken

down or used up• there was no starch left

1 (c) any one from• it doubled the speedaccept ‘it made it quicker’ or ‘it increased the speed’• it halved the time takenaccept ‘it takes less time’

1 (d) any one from• use the same amount of mixture or the same amount of enzyme and starchaccept ‘use the same size drops’• stir the mixture or stir the enzyme and starchaccept ‘use the same concentration of enzymeor starch or amylase’• use the same type of mixtureaccept ‘use the same concentration of enzymeor starch or amylase’

1 (e) (i) minerals and vitaminsanswers may be in either orderboth substances are required for the mark

1(ii) fibre

1M12. (a) (i) Answers may be in either order vitaminsaccept ‘vitamin C’

1 wateraccept ‘carbohydrates’do not accept ‘sugar’ or ‘starch’

1 (ii) Answers may be in either order fats

1 proteins

1 (b) Answers may be in either order minerals

1 fibreaccept ‘roughage’

1 (c) any two from• increases the surface area of the food or orangeaccept ‘increases the surface area’or ‘breaks it into smaller pieces’• breaks open cellsaccept ‘so you can get the nutrients out’• mixes it with saliva for easy swallowingaccept ‘for ease of swallowing’ or ‘to stop you choking’• mixes with saliva to start digestion



occurringaccept ‘to start digestion’ or ‘to mix enzymes with the food’or ‘to break it down’

2M13. (a)

food and drink

meal with theleast fat

meal with themost fibre

type of burger single burgeraccept ‘single’

double burgeraccept ‘double’

type of drink cola ororange juice

the drinks do notcontain fibre

type of potato baked potato baked potato

award one mark for each correct column2 (L3)

(b)

if more than four lines are drawn, deduct one mark for each incorrectly drawn line minimum mark zero

4 (L3)M14. (a) (i) speeds up clotting or the reactionaccept ‘reduces time for clotting’

1(ii) any one from• the pH is low in the stomachaccept ‘the pH is correct in the stomach’• hydrochloric acid is produced in the stomach• the stomach is acidic• it clots most quickly in acid conditions• the conditions in the stomach are ideal for the activity of the enzyme

1 (ii) it stopsaccept ‘it slows down’

1any one from• the acid is neutralised• the intestine is alkaline• the intestine is less acidaccept ‘all the milk was already clotted’

1 (b) (i) at 60°C the enzyme or rennin is

denatured or destroyed1

(ii) any one from• the enzyme is not denatured or destroyed at 0°C• the enzyme was only inactive at 0°C

1 (iii) any one from• test a greater number of temperaturesdo not accept ‘test a greater range of temperatures’• test more temperatures between 25°C and 60°C

1 (c) any one from• amino acids• polypeptides• peptides [1]



- ks3 8a nutrition and digestion ... · web viewinto beaker c, she put 50 cm3 pepsin solution and a...

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