Biology A-Level

Entrance Exam Instructions:

1. Answer all questions 2. Show all of your working out.

You will need:

1. Black pen 2. Pencil 3. Ruler 4. Calculator

Total marks: 85 Total time: 90 minutes

2

Q1. Figure 1 shows one type of white blood cell.

Figure 1

(a) What is structure A?

Tick one box.

Cell membrane

Cell wall

Cytoplasm

Nucleus

(1)

(b) White blood cells help to defend the body against pathogens.

How do the white blood cells do this?

Tick three boxes.

Clone pathogens

Engulf pathogens

Produce antibiotics

Produce antibodies

Produce antitoxins

Produce toxins

(3)

3

Measles is a serious disease. A person can die from measles.

Figure 2 shows the number of cases of measles in England and Wales between 2012 and 2015

Figure 2

(c) Use Figure 2 to calculate the decrease in the number of cases of measles between 2012 and 2015

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Answer = ______________________ cases

(2)

(d) Suggest one reason for the decrease in the number of cases of measles between 2012 and 2015

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(1)

(e) Antibiotics cannot be used to treat measles.

Suggest why.

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(1)

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(f) Gonorrhoea is a disease caused by a bacterium.

Gonorrhoea can be treated with antibiotics.

Give one other way to control the spread of gonorrhoea.

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(1)

A scientist investigated how effective different antibiotics were at killing gonorrhoea bacteria.

This is the method used.

1. Grow gonorrhoea bacteria on agar in a Petri dish. 2. Place one paper disc soaked in water onto the agar. 3. Place four other paper discs, each soaked in a different antibiotic, A, B, C, and D,

onto the agar. 4. Use the same sized paper discs and the same concentration of each antibiotic. 5. Incubate the Petri dish for 3 days.

Figure 3 shows the scientist’s results.

A clear area around the disc means the antibiotic has killed the bacteria.

Figure 3

(g) Give one control variable the scientist used.

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(1)

(h) Suggest why one disc was soaked in water.

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(1)

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(i) Which antibiotic in Figure 3 would be the best to treat gonorrhoea?

Give a reason for your answer.

Antibiotic ___________________________________________________________

Reason ____________________________________________________________

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(2)

(Total 13 marks)

Q2. In this question you will be assessed on using good English, organising information

clearly and using specialist terms where appropriate.

Deforestation affects the environment.

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

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 the atmosphere.

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Extra space _____________________________________________________________

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(Total 6 marks)

Q3. This question is about stem cells.

(a) Give one place in a plant where stem cells are found.

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(1)

(b) What is one economic use of plant stem cells?

Tick one box.

To create genetically modified crops

To create new species of plants

To increase variation in plants

To produce large numbers of identical plants

(1)

7

Embryonic stem cells divide by mitosis.

Figure 1 represents a cell cycle for a human embryonic stem cell.

Figure 1

(c) The mass of DNA in the cell at the start of the cycle is 6 picograms.

A picogram is 10−3 nanograms.

Convert 6 picograms to grams.

Give your answer in standard form.

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Mass = _____________________ g

(1)

(d) The time taken for this complete cell cycle is 15 hours.

Calculate how many hours the cell spent in mitosis.

Give your answer to 3 significant figures.

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Time spent in mitosis = _____________________ hours

(2)

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(e) Describe what happens in each of the three stages of the cell cycle.

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(5)

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(f) Figure 2 shows how embryonic stem cells are produced in therapeutic cloning for use in patients.

Figure 2

Give two advantages and two disadvantages of therapeutic cloning in medical treatments.

Use Figure 2 to help you.

Advantage 1 ________________________________________________________

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Advantage 2 ________________________________________________________

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Disadvantage 1 ______________________________________________________

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Disadvantage 2 ______________________________________________________

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(4)

(Total 14 marks)

10

Q4. Pompe disorder is an inherited condition that affects thousands of people.

Pompe disorder is caused by the GAA gene.

(a) What is a gene made of?

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(1)

Figure 1 shows the inheritance of Pompe disorder in one family.

Figure 1

Pompe disorder is caused by a recessive allele.

r is the allele for Pompe disorder

R is the allele for no Pompe disorder

(b) Person 2 has Pompe disorder.

What is the genotype of person 2?

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(1)

(c) Look at Figure 1.

Explain how we can tell Pompe disorder is caused by a recessive allele.

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(2)

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(d) Persons 6 and 7 decide to have another child.

Complete the genetic diagram in Figure 2.

Figure 2

(2)

(e) Draw a ring around any offspring in Figure 2 who will have Pompe disorder.

(1)

(f) What is the probability of persons 6 and 7 having another child with Pompe disorder?

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(1)

(g) A new drug to treat Pompe disorder has been successfullly trialled on mice.

The drug now has approval for the next stage of clinical testing.

Describe the next steps in testing the new drug before it can be approved for use.

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(4)

(Total 12 marks)

12

Q5. This question is about cell structures.

(a) Draw one line from each cell structure to the type of cell where the structure is found.

Cell Structure Type of cell where

the structure is found

Nucleus Prokaryotic cells

Permanent vacuole Plant cells only

Plasmid Eukaryotic cells

(2)

(b) Figure 1 shows a plant cell.

Figure 1

What are the names of structures A, B and C?

Tick one box.

Structure A Structure B Structure C

Chloroplast Vacuole Cell wall

Nucleus Chloroplast Cell membrane

Vacuole Mitochondrion Cell membrane

Vacuole Ribosome Cell wall

(1)

13

A student observed slides of onion cells using a microscope.

Figure 2 shows two of the slides the student observed.

Figure 2

The cells on the slides are not clear to see.

(c) Describe how the student should adjust the microscope to see the cells on Slide A more clearly.

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(1)

(d) Describe how the student should adjust the microscope to see the cells on Slide B more clearly.

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(2)

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(e) The student made the necessary adjustments to get a clear image.

Figure 3 shows the student’s drawing of one of the cells.

Figure 3

The real length of the cell was 280 micrometres (µm).

Calculate the magnification of the drawing.

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Magnification = × _________________________

(3)

(Total 9 marks)

15

Q6. Starch 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.

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(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.

Explain why.

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(2)

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(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.

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Answer _____________ mol per dm3

(1)

(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.

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Answer _______________________ mol per dm3 per minute

(2)

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

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(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.

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(2)

(Total 10 marks)

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Q7. Insulin controls blood glucose concentration.

(a) The rate at which blood glucose concentration changes is affected by the food eaten.

In an experiment a person who does not have diabetes ate two slices of white bread. The change in her blood glucose concentration was recorded over the next 120 minutes. The experiment was repeated; first with two slices of brown bread and then with two slices of wholemeal bread.

The graph shows the results of the three experiments.

(i) Which type of bread would be most suitable for a person with diabetes?

Type of bread ___________________________________________

Give two reasons for your answer.

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2. ____________________________________________________________

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(2)

(ii) Explain, as fully as you can, the reasons for the changes in blood glucose concentration when the person ate the brown bread.

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(4)

(b) Pancreatic-cell transplantation is a new treatment for diabetes. Insulin-making cells are taken from up to three dead donors. The cells are kept alive before being injected into the diabetic in a small operation. The cells soon begin to make insulin.

In one recent study 58 % of recipients of pancreatic-cell transplants no longer needed insulin injections.

Give the advantages and disadvantages of the new treatment for diabetes compared with using insulin injections.

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(3)

(Total 9 marks)

21

Section B: A-Level Head Start Content

1. What does the ‘primary structure’ of a protein refer to? 1 mark ___________________________________________________________________ ___________________________________________________________________

2. What is a disaccharide? 1 mark ___________________________________________________________________ ___________________________________________________________________

3. What is the name of a pair of chromosomes that contain the same genes? One from each pair comes from your mother and the other from your father. 1 mark

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4. Which animal has a greater surface area to volume ratio: Animal A: (5.6 : 1) or Animal B: (0.56 : 1). 1 mark

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5. Explain why the column of water in the xylem is under tension? 2 marks ___________________________________________________________________ ___________________________________________________________________

6. Write the sequence of mRNA that will form if the following DNA sequence acts as a template: ATT GCC AGC. 2 marks ___________________________________________________________________

7. Which two sets of muscles contract when we breathe in? 1 mark 8. Compare the role of a phagocyte to a B-cell. 2 marks

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9. Which property of haemoglobin means that rapidly respiring cells get more oxygen? 1 mark ___________________________________________________________________ ___________________________________________________________________