broughton hall catholic high school - one heart, one mind · web viewq2. the chemistry of food a...

Year 11 into 12 Biology Transition WorkTopic 4.1 Biological moleculesPast paper question pack

Name: ________________________

Class: ________________________

Date: ________________________

Time: 103 minutes

Marks: 101 marks

Comments: Email or submit this to Mrs Williams [email protected]

E

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Q1. The chemistry of foodAn athlete decides to try a new type of protein drink after he exercises.

(a) The athlete tests the protein drink to check it contains protein.

Which solution is used to test for protein in the drink?

Tick one box.

Benedict’s

Biuret

Iodine

Universal indicator

(1)

(b) What colour will the solution turn to if there is protein in the drink?

Tick one box.

Blue-black

Purple

Red

Yellow

(1)

Figure 1 shows the proportion of different nutrients in the protein drink.

Figure 1

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(c) What is the ratio of sugar to protein in the protein drink?

1:1 1:0:6 1:2 1:1:6

(1)

(d) Why is a high protein diet useful to an athlete?

Tick one box.

Provides amino acids to make new muscle.

Provides fatty acids to produce urea.

Provides glucose for energy.

Provides lactic acid for anaerobic respiration.

(1)

When the athlete drinks the protein drink the substances are digested.

The products of digestion are absorbed into the bloodstream.

Absorption happens in the small intestine.

Figure 2 shows a section of the small intestine.

Figure 2

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(e) How is the small intestine in Figure 2 adapted to absorb the products of digestion quickly?

Tick two boxes.

It has a large surface area.

It has a long diffusion pathway.

It has a thin surface.

The concentration inside the small intestine is low.

It has a poor blood supply.

(2)

(f) Figure 3 shows the proportion of different nutrients in four protein drinks.

Figure 3

Which protein drink should an athlete with diabetes use?

Give a reason for your answer.

Drink ____________________

Reason ____________________________________________________________

___________________________________________________________________(2)

(Total 8 marks)

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Q2. The chemistry of foodA popular diet book claims that a low-carbohydrate diet results in quicker weight loss and a more healthy body than a low-fat diet.

Scientists carried out an investigation to see if this claim is true.

• They used 120 overweight volunteers divided into two equal groups.

• Group 1 was given a diet containing less than 20 g of carbohydrate per day.

• Group 2 was given a low-fat diet. This contained less than 30% of energy from fat and less than 300 mg of cholesterol per day.

• Both groups were given the same exercise programmes and a weekly information meeting.

• Both groups were allowed only 2000 kilocalories per day.

The results after 24 weeks are shown in the table.

Group 1Low-carbohydrate diet

Group 2Low-fat diet

Proportion of volunteerswho completed the trial 76% 57%

Mean change in body mass −12.9% −6.7%

Mean change in body fatmass −9.4 kg −4.8 kg

Mean change in bloodHDL concentration +55 mg per litre −16 mg per litre

Mean change in bloodLDL concentration +16 mg per litre −74 mg per litre

(a) What was the independent variable in this investigation?

___________________________________________________________________(1)

(b) Give one variable that the scientists tried to control in this investigation.

___________________________________________________________________(1)

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(c) Give two ways in which the method used by the scientists could have led to unreliable data.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________(2)

(d) Does the data support the claim in the book?

Draw a ring around your answer. Yes / No

Give two reasons for your answer.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________(2)

(Total 6 marks)

Q3. The chemistry of foodThe table shows the amounts of carbohydrate, fat and protein in 100 g portions of five foods, A - E.

MASS IN 100 g PORTION (g)

FOOD CARBOHYDRATE FAT PROTEIN

A 0 1 20

B 50 2 8

C 0 82 0

D 12 0 1

E 20 0 2

(a) A person eats 50 g of food E.

How much carbohydrate would the person eat?

________ g(1)

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(b) Describe, in as much detail as you can, what happens to the protein after food A is swallowed.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(4)

(Total 5 marks)

Q4. The chemistry of foodVitamin C is needed in the diet to prevent a deficiency disease called scurvy.

Fruits such as oranges contain vitamin C.

A group of students investigated the amount of vitamin C in four different fruit juices.

The method the students used is shown below.

DCPIP solution is blue. When vitamin C is added to DCPIP solution the blue colour disappears.

The mean results for the students are shown in the table.

Type of fruit juice

Mean number of drops of fruit juice needed to decolourise

DCPIP solution

Apple More than 30

Grapefruit 9

Orange 11

Lemon 6

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(a) (i) What type of variable is the number of drops of fruit juice needed to decolourise the DCPIP solution?

______________________________________________________________(1)

(ii) Give one conclusion that can be made from the results shown in the table above.

______________________________________________________________

______________________________________________________________(1)

(b) (i) The food label on a carton of grapefruit juice states that 100 cm3 of juice contains 25 mg of vitamin C.

The Recommended Daily Amount (RDA) of vitamin C for an adult is 80 mg.

What percentage of the recommended daily amount of vitamin C is provided by a 200 cm3 serving of grapefruit juice?

______________________________________________________________

______________________________________________________________

________________________ %(1)

(ii) The RDAs for vitamins given on food packaging labels are only guideline values.

Suggest why the values are only guidelines.

______________________________________________________________

______________________________________________________________(1)

(Total 4 marks)

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Q5. EnzymesThe diagram below shows the human digestive system.

(a) (i) What is Organ A?

Draw a ring around the correct answer.

gall bladder liver stomach(1)

(ii) What is Organ B?

Draw a ring around the correct answer.

large intestine pancreas small intestine(1)

(b) Digestive enzymes are made by different organs in the digestive system.

Complete the table below putting a tick (✓) or cross (✕) in the boxes.

The first row has been done for you.

Organ producing enzyme

salivary glands stomach pancreas small

intestine

Enzyme

amylase ✓ ✕ ✓ ✓

lipase

protease

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(2)

(c) The stomach also makes hydrochloric acid.

How does the acid help digestion?

___________________________________________________________________

___________________________________________________________________(1)

(d) Draw one line from each digestive enzyme to the correct breakdown product.

Digestive enzyme Breakdown products

amino acids.

Amylase breaks down starch into……

bases.

Lipase breaks down fats into…

fatty acids and glycerol.

Protease breaks down proteins into…

sugars.

(3)(Total 8 marks)

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Q6. Enzymes(a) The graph shows the effect of pH on the activities of three enzymes, X, Y and Z.

These enzymes help to digest food in the human digestive system.Each enzyme is produced by a different part of the digestive system.

pH

(i) What is the optimum (best) pH for the action of enzyme Z?

__________________(1)

(ii) The stomach makes a substance that gives the correct pH for enzyme action in the human stomach.

Name this substance. ____________________________________________(1)

(iii) Which enzyme, X, Y or Z, will work best in the human stomach?

__________________(1)

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

Different parts of the human digestive system help to break down molecules of fat so that they can be absorbed into the body.

Describe how.

To gain full marks you should refer to:

• the enzyme and where the enzyme is produced

• the products of digestion

• any other chemicals involved.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(6)

(Total 9 marks)

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Q7. EnzymesCatalase is an enzyme found in many different tissues in plants and animals. It speeds up the rate of the following reaction.

hydrogen peroxide water + oxygen

Figure 1 shows a 25-day-old broad bean seedling.

Some students investigated whether different parts of bean seedlings contained different amounts of catalase.

The students:• put hydrogen peroxide into five test tubes

• added a different part of a bean seedling to each tube

• recorded the results after half a minute.

If there was catalase in part of the seedling, oxygen gas was given off.When oxygen gas is given off, foam is produced in the tubes.

Figure 2 shows the results.

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The students made the following conclusions:• most parts of a bean seedling contain catalase

• the seed contains a lot of catalase

• stems and roots have quite a lot of catalase

• the leaves have a little bit of catalase

• the seed coat has hardly any catalase.

The students’ teacher said that the students needed to improve their investigation in order to make valid conclusions.

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

Describe how you would carry out an investigation to compare the amounts of catalase in different parts of bean seedlings.

You should include details of how you would make sure your results give a valid comparison of the amounts of catalase.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(6)

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(b) Scientists investigated the effect of pH on the activity of the enzyme catalase in a fungus.

The table below shows the scientists’ results.

pHEnzyme activity in arbitrary units

Test 1 Test 2 Test 3 Test 4 Test 5 Mean

3.0 0 0 0 0 0 0

4.0 6 5 8 4 7 6

5.0 38 65 41 42 39

5.5 80 86 82 84 88 84

6.0 100 99 96 103 102 100

6.5 94 92 90 93 91 92

7.0 61 63 61 62 63 62

8.0 22 22 21 24 21 22

(i) Calculate the mean enzyme activity at pH 5.0.

______________________________________________________________

______________________________________________________________

Mean = _____________ arbitrary units(2)

(ii) On the graph paper in Figure 3, draw a graph to show the scientists’ results.

Remember to:• add a label to the vertical axis

• plot the mean values of enzyme activity

• draw a line of best fit.

Figure 3

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(4)

(iii) At what pH does the enzyme work best?

____________________(1)

(iv) Predict the activity of the enzyme at pH 9.0.

____________________ arbitrary units(1)

(v) Suggest why the enzyme’s activity at pH 3.0 is zero.

______________________________________________________________

______________________________________________________________(1)

(Total 15 marks)

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Q8. EnzymesAmylase is an enzyme that digests starch.

A student investigated the effect of pH on the activity of amylase.

This is the method used.

1. Mix amylase solution and starch suspension in a boiling tube.

2. Put the boiling tube into a water bath at 25 °C.

3. Remove a drop of the mixture every 30 seconds and test it for the presence of starch.

4. Repeat the investigation at different pH values.

The table below shows the students’ results.

pH Time when no starch was detected in minutes

5.0 7.0

5.5 4.5

6.0 3.0

6.5 2.0

7.0 1.5

7.5 1.5

8.0 2.0

(a) The student concluded pH 7.25 was the optimum pH for the amylase enzyme.

This is not a valid conclusion.

Suggest two reasons why.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________(2)

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(b) The student did another investigation.


1. Put amylase solution and starch suspension into a boiling tube.

2. Make the pH 7.25.

3. Put the boiling tube into a water bath at 25 °C.

4. Measure the amount of sugar produced every 30 seconds.

The results are shown in the figure below.

Calculate the mean rate of sugar produced per minute during the first 5 minutes.

___________________________________________________________________

___________________________________________________________________

Mean rate = ________________ units per minute(2)

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(c) Iodine solution is added to a sample taken from the boiling tube after 10 minutes and 60 minutes.

Suggest what you would see in these samples.

After 10 minutes _____________________________________________________

___________________________________________________________________

.After 60 minutes _____________________________________________________

___________________________________________________________________(2)

(d) The scientist repeated the investigation at 37 °C.

Draw a line on the figure above to show the predicted results.(2)

(Total 8 marks)

Q9. EnzymesAmylase catalyses the breakdown of starch into sugars.

A student investigated the effect of amylase on the reaction at different temperatures.

Figure 1 shows the apparatus the student used.

Figure 1


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1. Put starch suspension into a test tube.

2. Add amylase solution.

3. Put the test tube in a beaker of water at 15 °C.

4. Remove a small sample of the mixture every 30 seconds and put in a spotting tile.

5. Test the sample for starch.

6. Time how long it takes to break down all of the starch in the mixture.

7. Repeat steps 1–5 at 20 °C, 25 °C and 30 °C.

8. Repeat for each temperature twice more.

The table below shows the student’s results.

Time taken until there was no starch in the sample in minutes

Temperature in °C

Test 1 Test 2 Test 3 Mean

15 6.1 9.4 10.0 8.5

20 4.8 5.0 4.6 4.8

25 3.0 2.5 3.0 3.2

30 1.5 2.0 2.0

(a) One of the results in the table above is anomalous.

Draw a ring around the anomalous result.(1)

(b) Calculate the mean for 30 °C.

___________________________________________________________________

___________________________________________________________________(1)

(c) Figure 2 shows a graph of the student’s results.

Figure 2

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Use the graph to predict how long it would take to break down all of the starch at 10 °C.

Time = _________________ minutes(1)

(d) The student tested samples of the mixture for starch every 30 seconds.

In each test she added one drop of iodine to the sample in the spotting tile.

Predict the colour of the samples from the 20 °C test at 4.0 minutes and 7.0 minutes.

Colour at 4.0 minutes __________________________________________

Colour at 7.0 minutes __________________________________________(2)

(e) The student did a fourth test at 30 °C.

In this test the starch did not break down, even after 45 minutes.

Why did the amylase not break down the starch in this test?

Tick one box.

The amylase solution and the starch suspension were mixed before the start of the experiment.

The amylase solution had been prepared with water at 95 °C.

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The amylase solution had been prepared with water at 20 °C.

The amylase solution had been stored in the fridge.

(1)

(f) The student made the following conclusion about the optimum temperature for amylase to work at.

‘Amylase works fastest at 40 °C’

Her teacher said that this is not a valid conclusion from her results.

Describe how the student could change her method to give results that would improve the validity of her conclusion.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(6)

(Total 12 marks)

Q10. EnzymesStarch is broken down into sugar by amylase. Amylase is produced in the salivary glands.

(a) Name two other organs in the digestive system which produce amylase.

____________________________ and ____________________________(2)

(b) A colorimeter measures colour intensity by measuring the percentage of light that passes through a solution.Graph 1 shows the percentage of light passing through sugar solutions of different concentrations to which a test reagent has been added.

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Students used a colorimeter to compare the starch-digesting ability of amylase enzymes obtained from two organs, P and Q.

• The students collected 5 cm3 samples of amylase from P and Q and placed them into a water-bath at 40 °C.

• Two test tubes containing 10 cm3 samples of starch solution were also placed into the water-bath.

• All the tubes were left in the water-bath for 10 minutes.

• Each amylase sample was added to one of the tubes containing the starch solution.

• The test tubes were placed back into the water-bath.

• Every minute, a few drops were taken from each tube, the test reagent was added and the percentage of light passing through this solution was measured in the colorimeter.

The tubes containing amylase samples and starch solution were left in the water-bath for ten minutes before the amylase was added to the starch.

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Explain why.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(c) Graph 2 shows how the readings from the colorimeter changed over the next 20 minutes.

(i) Use Graph 1 and Graph 2 to determine the concentration of sugar in the mixture from organ Q after 20 minutes.

______________________________________________________________

Answer _____________ mol per dm3

(1)

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(ii) Use your answer to (c)(i) to calculate the rate at which sugar was produced in the mixture containing amylase from organ Q.

Show clearly how you work out your answer.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Answer _______________________ mol per dm3 per minute(2)

(iii) Suggest why the amount of light passing through the mixture from organ P did not change after 16 minutes.

______________________________________________________________

______________________________________________________________

______________________________________________________________(1)

(iv) One of the students suggested that they could have completed their experiment more quickly if the temperature of the water-bath had been set at 80 °C.

This would not have been the case.

Explain why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(Total 10 marks)

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Q11. DNADNA is the genetic material of human cells.

Figure 1 shows the structure of part of a DNA molecule.

(a) (i) Describe where DNA is found in a human cell.

______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(ii) When a cell divides by mitosis the new cells are genetically identical.

What causes the cells to be genetically identical?

______________________________________________________________

______________________________________________________________(1)

(b) Many genes have different forms called alleles.

(i) A person has polydactyly (extra fingers or toes). Polydactyly is caused by a dominant allele.What is the smallest number of copies of the dominant allele for polydactyly that could be found in a body cell of this person?

______________(1)

(ii) Another person has cystic fibrosis. Cystic fibrosis (CF) is caused by a recessive allele.How many copies of the recessive CF allele are there in a body cell of this person?

______________(1)

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(c) A burglar broke into a house. The burglar cut his hand on some broken glass. Scientists extracted DNA from the blood on the broken glass.

The scientists analysed the DNA from the glass and DNA from three suspects, A, B and C. The scientists used a method called DNA fingerprinting.

Figure 2 shows the scientists’ results.

Which suspect, A, B or C, is most likely to have been the burglar?

Tick ( ) one box.

A

B

C

(1)(Total 6 marks)

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Q12. DNAThe diagram below shows the production of human sperm cells.

(a) Name the organ where the processes shown in the diagram above take place.

______________________________(1)

(b) (i) Not every cell in the diagram above contains the same amount of DNA.

Cell A contains 6.6 picograms of DNA (1 picogram = 10-12 grams).

How much DNA is there in each of the following cells?

Cell B _____________ picograms

Cell C _____________ picograms

Cell E _____________ picograms(2)

(ii) How much DNA would there be in a fertilised egg cell?

_____________________ picograms(1)

(iii) A fertilised egg cell divides many times to form an embryo.

Name this type of cell division.

______________________________(1)

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(c) After a baby is born, stem cells may be collected from the umbilical cord. These can be frozen and stored for possible use in the future.

(i) What are stem cells?

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(ii) Suggest why it is ethically more acceptable to take stem cells from an umbilical cord instead of using stem cells from a 4-day-old embryo produced by In Vitro Fertilisation (IVF).

______________________________________________________________

______________________________________________________________(1)

(iii) Stem cells taken from a child’s umbilical cord could be used to treat a condition later in that child’s life.

Give one advantage of using the child’s own umbilical cord stem cells instead of using stem cells donated from another person.

______________________________________________________________

______________________________________________________________(1)

(iv) Why would it not be possible to treat a genetic disorder in a child using his own umbilical cord stem cells?

______________________________________________________________

______________________________________________________________(1)

(Total 10 marks)

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broughton hall catholic high school - one heart, one mind · web viewq2. the chemistry of food a...

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