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Combined Science B (21st Century) · OCR J260 · Paper 5 · June 2018

OCR GCSE Combined Science B (21st Century) Paper 5 June 2018 question paper

OCR J260 · Paper 5

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Question 1

Read the newspaper headline.

Figure for question 1

Having only males born into a family for this length of time is very unusual.

(a)

Use your knowledge of how human sex is determined to explain why having only males is very unusual.

Use the Punnett square in your answer.

Figure for question 1

[5]

Answer
Mark scheme for question 1(a)
(b)

Gametes are made by cell division.

A fertilised egg divides to make body cells using a different type of cell division.

Complete the table describing the two types of cell division.

Figure for question 1

[5]

Answer
Mark scheme for question 1(b)

Question 2

Scientists collected data on blood cholesterol levels and death from heart disease in men.

The graph in Fig. 2.1 shows the relationship between blood cholesterol and the death rate from heart disease in the United States, Japan and two areas of Europe.

Figure for question 2
(a)(i)

Blood cholesterol levels are measured in millimoles per litre (mmol / l).

How many moles are there in a millimole?

Question 2, shown as an image

0.001 0.01 0.1 10 100 1000

[1]

Answer
Mark scheme for question 2(a)(i)
(a)(ii)

A student reads off the graph and concludes that the death rate for men with a blood cholesterol level of 5.20 mmol / l is 15 deaths from heart disease per 1000 men.

Is the student’s conclusion correct?

Use data from the graph in Fig. 2.1 to explain your answer.

[3]

Answer
Mark scheme for question 2(a)(ii)
(b)(i)

A man in the United States has a blood cholesterol level of 6.50 mmol / l.

The graph in Fig. 2.1 shows that 15 out of every 1000 men with this blood cholesterol level will die from heart disease.

Calculate the probability that he will die from heart disease.

Give your answer to 1 significant figure.

[2]

Answer
Mark scheme for question 2(b)(i)
(b)(ii)

In a sample of 1000 men from the United States, 20 died from heart disease.

Use the graph in Fig. 2.1 to estimate the mean blood cholesterol level of these men.

Blood cholesterol level =........ mmol /

[1]

Answer
Mark scheme for question 2(b)(ii)
(c)

The scientists could collect other information to help explain the data on the graph.

One example of other information they could collect is the ages of the men in the study.

Suggest other examples of information they could collect to help explain the data.

[2]

Answer
Mark scheme for question 2(c)

Question 3

Hormones control many processes in the human body.

(a)

The graph shows changes in the levels of hormones that control the menstrual cycle in one female human during one complete cycle.

Figure for question 3
(a)(i)

On which day during this menstrual cycle did ovulation take place?

Explain your answer.

[2]

Answer
Mark scheme for question 3(a)(i)
(a)(ii)

During this menstrual cycle the egg was fertilised. This caused a change in hormone levels and the female did not menstruate.

Draw one line to join the correct change in hormone levels to its effect to explain why she did not menstruate.

Figure for question 3

[2]

Answer
Mark scheme for question 3(a)(ii)
(b)

A different female is being treated for infertility. She has to have injections of the hormone FSH.

Explain how these injections will help to treat her infertility.

[2]

Answer
Mark scheme for question 3(b)
(c)

Thyroxine is another hormone produced in the human body.

Describe the effects that thyroxine has in the body and explain how production of thyroxine is controlled.

[4]

Answer
Mark scheme for question 3(c)

Question 4

Approximately one quarter of all the trees in Great Britain are ash trees.

In 2012 scientists found trees with a disease called ash dieback.

(a)

Describe the cause of ash dieback and how it is spread.

[3]

Answer
Mark scheme for question 4(a)
(b)

Scientists have collected data on the spread of ash dieback since 2012.

The scientists divided Scotland, England and Wales into squares.

Each year they recorded the number of squares in which ash dieback was identified for the first time.

Table 4.1 shows their results.

Figure for question 4
(b)(i)

The scientists calculated that 50.6% of all squares in Wales had ash dieback.

Calculate the total number of squares in Wales.

Give your answer to 3 significant figures.

[3]

Answer
Mark scheme for question 4(b)(i)
(b)(ii)

Table 4.1 shows that the spread of ash dieback was slower overall in Scotland than in England.

Suggest some possible explanations for this.

[3]

Answer
Mark scheme for question 4(b)(ii)
(c)

Research shows that some British ash trees have some resistance to ash dieback.

Describe how ash trees could be selectively bred to increase resistance to ash dieback.

[3]

Answer
Mark scheme for question 4(c)
(d)

Some corn plants have been genetically engineered to be resistant to disease.

Genetic material from a different organism was added to the corn. The genetic material allows the corn to make toxins that kill insects.

(d)(i)

Complete the sentences to describe the main steps in the process of genetically engineering corn in this way.

Choose the correct words from the list.

Each word may be used once, more than once or not at all.

amino acid enzyme gamete gene

genome plasmid

The........ that codes for the toxin is isolated from the original

organism using a specific........

The isolated........ is then inserted into a

........, which is added into a bacterium.

The bacterium is used to infect cells from corn.

The new genetic material becomes part of the........ in the corn

cells.

[5]

Answer
Mark scheme for question 4(d)(i)
(d)(ii)

Describe some of the risks of growing genetically engineered corn.

[2]

Answer
Mark scheme for question 4(d)(ii)

Question 5

Darwin published his theory of evolution by natural selection in 1859.

(a)

* Many scientists have carried out experiments to test Darwin’s theory.

In one laboratory experiment a scientist used fruit flies. The diagram illustrates the experiment

Figure for question 5

The results of the experiment are shown in the table.

Mating pairNumber of fertile
MaleFemaleoffspring
From tank 1From tank 119
From tank 1From tank 20
From tank 2From tank 10
From tank 2From tank 218

Describe the results from the experiment and use ideas about evolution to explain what has happened.

[6]

Answer
Mark scheme for question 5(a)
(b)

Scientists have found evidence that supports the theory of evolution by natural selection.

Some of this evidence is provided by fossils.

Describe two ways in which fossils have provided evidence of evolution.

[2]

Answer
Mark scheme for question 5(b)
(c)

Living and fossilised organisms can be classified into groups.

Early classification systems put organisms into large groups called kingdoms.

Later evidence suggested that the kingdoms of animals, plants, fungi and protists could be grouped into one large domain. The evidence was the observation of the cell nucleus.

What name is given to the domain that contains all organisms with a cell nucleus?

[1]

Answer
Mark scheme for question 5(c)

Question 6

Amaya is planning an investigation.

She wants to find out how temperature affects the rate of photosynthesis.

The information below is taken from her lab notebook.

Figure for question 6
(a)(i)

The bubbles contain oxygen gas.

During which stage of photosynthesis is oxygen gas formed?

[1]

Answer
Mark scheme for question 6(a)(i)
(a)(ii)

What factors should Amaya keep the same in each repeat to make sure her investigation produces valid data?

[2]

Answer
Mark scheme for question 6(a)(ii)
(a)(iii)

There are different methods that can be used to collect the gas produced by the pondweed.

Describe a different method that Amaya could use and explain why it is better than the method shown in Amaya’s notes.

[2]

Answer
Mark scheme for question 6(a)(iii)
(b)

Amaya draws a graph of her results.

Figure for question 6
(b)(i)

Use the graph to calculate the rate of gas production at 40 °C.

Rate =........ bubbles per minute

[2]

Answer
Mark scheme for question 6(b)(i)
(b)(ii)

Amaya concludes that increasing the temperature above 30 °C does not cause a large increase in the number of bubbles produced.

Use your knowledge of the requirements of photosynthesis to explain why.

[2]

Answer
Mark scheme for question 6(b)(ii)
(b)(iii)

Amaya does a second investigation into the effect of temperature on the rate of photosynthesis.

For this investigation she adds sodium hydrogen carbonate to the pond water.

Draw a line on the graph to show the pattern of results you would predict for this investigation.

[2]

Answer
Mark scheme for question 6(b)(iii)
(c)

Amaya repeats the investigation again, but this time at 60 °C.

Write a testable hypothesis for the investigation at 60 °C and explain why this occurs.

[2]

Answer
Mark scheme for question 6(c)
(d)

Glucose is a product of photosynthesis.

Write down the name of the reagent you would use to test for the presence of glucose.

[1]

Answer
Mark scheme for question 6(d)

Question 7

Some students are learning about cells.

They look at some diagrams of different cell types:

Figure for question 7
(a)

Use information in the diagrams to answer the following questions.

(a)(i)

Which cell, A, B or C, is a prokaryotic cell?

[2]

Answer
Mark scheme for question 7(a)(i)
(a)(ii)

Which cell, A, B or C, is a yeast cell?

[2]

Answer
Mark scheme for question 7(a)(ii)
(a)(iii)

Two of the cells also contain an organelle that is not shown in the diagrams. Some of the reactions of aerobic respiration take place in this organelle.

Write down the name of the organelle and which two cells, from A, B and C, will contain this organelle.

Name of organelle........

Found in cells........ and........

[2]

Answer
Mark scheme for question 7(a)(iii)
(b)
Figure for question 7

[3]

Answer
Mark scheme for question 7(b)
(c)

The word summaries are simple models of cellular respiration. In cells, respiration is a complex process involving several reactions.

A paper in a scientific journal includes some more detailed models of anaerobic and aerobic respiration in yeast.

(c)(i)

The students have confidence in the information in the paper.

Explain why.

[2]

Answer
Mark scheme for question 7(c)(i)
(c)(ii)

The models of anaerobic and aerobic respiration from the paper are shown in the diagram.

Figure for question 7

These models show that:

• the first reactions of anaerobic and aerobic respiration are the same

• anaerobic and aerobic respiration produce different amounts of ATP.

Calculate the anaerobic:aerobic ratio of ATP produced by cellular respiration in yeast.

anaerobic:aerobic ratio of ATP produced =........:........

[2]

Answer
Mark scheme for question 7(c)(ii)
(c)(iii)

Look at the diagram showing the models of respiration.

Yeast will use anaerobic respiration even when oxygen is available.

Which two statements, taken together, could explain this?

Tick (✓) two boxes.

Question 7, shown as an image
Question 7, shown as an image

[2]

Answer
Mark scheme for question 7(c)(iii)

Question 8

Jack has been feeling tired and short of breath. He visits his doctor.

The doctor thinks Jack may have a problem with his heart valves and sends him for a scan of the heart.

Jack’s scan shows he has a faulty valve between the left atrium and the left ventricle.

(a)

Draw a circle on the diagram of the heart around the valve between the left atrium and the left ventricle.

Figure for question 8

[1]

Answer
Mark scheme for question 8(a)
(b)

Explain to Jack the function of heart valves and why his faulty valve is making him feel tired and breathless.

[3]

Answer
Mark scheme for question 8(b)
(c)

Write down one other type of structure in the circulatory system that has valves.

[1]

Answer
Mark scheme for question 8(c)
(d)

This information is about Jack’s circulatory system:

• The volume of blood pumped out by Jack’s heart in one beat is 40 cm3.

• Jack’s resting pulse rate is 80 beats per minute.

• When Jack is exercising, his pulse rate increases by 90%.

Calculate the volume of blood, in litres, pumped out by Jack’s heart in one minute when he is exercising.

Volume =........ litres

[4]

Answer
Mark scheme for question 8(d)

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