OCR GCSE Biology B (21st Century) Breadth in Biology Higher June 2018 question paper J257/03

The Galapagos Islands are a group of 13 islands found in the Pacific Ocean.

Charles Darwin visited the Galapagos Islands during the 19th century.

He collected samples and made observations.

This work helped Darwin to develop a new explanation for the evolution of species.

Which of the following are observations made by Darwin?

Tick (✓) two boxes.

There are differences between fossils and living examples of similar organisms.

Isolated populations of the same species living in different places have different characteristics.

Darwin suggested a theory to explain his observations.

Write down the name of the theory he suggested.

Algae live in the marine environment around the Galapagos Islands.

Photosynthesis takes place in the cells of algae.

In which cell structure does photosynthesis take place?

Many factors can limit the rate of photosynthesis.

Which factor will not limit the rate of photosynthesis in the algae?

carbon dioxide concentration light intensity temperature water availability

The food web shows the feeding relationships of some Galapagos Islands species.

A weather event called El Niño occurs every three years. This causes the population of algae to decrease.

Explain what effect this could have on the population of marine iguanas.

Scientists have discovered that during this event the marine iguanas can shrink in size.

The length of the marine iguana is determined by measuring the distance from the snout to the end of the tail.

Below is a drawing of a marine iguana.

Use the scale bar to calculate the actual length of this marine iguana in metres.

Some marine iguanas can shrink by up to 20% of their original length.

Calculate the length of this marine iguana after maximum shrinkage.

Scientists calculated the change in body length of the iguanas and measured how long they survived during the El Niño event.

The results are shown in the graph.

What can be concluded from the data?

Tick (✓) two boxes.

The change in body length made no difference to the survival time of the marine iguanas.

The marine iguanas that decreased in size the most on average lived for a greater length of time.

The marine iguanas that did not decrease in size survived for approximately 2 years less than the marine iguanas that decreased in size by up to 60 mm.

The marine iguanas that decreased in size by 20 mm survived more than double the length of time than those that did not change in size.

A student is carrying out a field investigation to determine the population of woodlice in the school’s wildlife garden.

Describe a method the student could use to determine the population size of woodlice.

Woodlice are often found under logs and bark where it is damp.

Suggest why woodlice prefer damp places.

Different areas of the brain are responsible for different functions.

Three areas have been labelled A, B and C on the diagram of the brain.

The table describes the functions of areas A, B and C.

Complete the table by writing the correct area of the brain for each function.

Scientists want to find out more about the functions of the brain. One way they can do this is to use patients with brain damage.

Suggest why there are concerns about using patients with brain damage.

Write down one other way scientists could study the brain.

The cerebral cortex is a highly folded area of the brain made up of billions of neurons.

Describe the features of a neuron that allow it to transmit electrical impulses quickly and over long distances.

Parkinson’s disease is a disease of the central nervous system.

It is caused by the loss of neurons in one part of the brain. These neurons are responsible for producing a transmitter substance called dopamine.

Dopamine acts as a transmitter substance in parts of the brain and nervous system that control movement.

Which neurons are most likely to be affected by Parkinson’s disease?

Tick (✓) one box.

At a synapse, transmitter substances are released from the first neuron.

Which word describes how the transmitter substances move across the gap from the first neuron to the second neuron?

Tick (✓) one box.

Scientists have been investigating the use of stem cells in the treatment of Parkinson’s disease.

Suggest one feature of stem cells that makes them useful in the treatment of Parkinson’s disease.

Plants respond to their environment.

What term is used to describe a plant’s growth response to light?

The growth response to light can be explained by the distribution of the plant hormone auxin in the plant shoot.

Jamal finds three diagrams that could explain what happens in the plant shoot.

Which diagram, A, B or C, best explains what happens to make the plant shoot grow towards the light?

Explain your choice.

Diagram........

Explanation........

Jamal’s teacher gives him two boxes of cress seedlings, each box contains ten seedlings.

Describe an experiment Jamal could do to investigate the growth response to light in the cress seedlings.

A gardener is growing fruit. He wants to ripen his fruit quickly and decides to use the plant hormone gibberellin.

Do you agree with his choice of hormone?

Explain your answer.

Plants can be infected by communicable diseases, so they need to protect themselves against pathogens.

Describe one chemical defence and one physical defence that plants have against pathogens.

Chemical defence........

Physical defence........

State the function of stomata in plants.

Cancer is a non-communicable disease.

Describe what causes cancer.

Identify one factor that could increase a person’s risk of developing cancer.

In the past it has been estimated that 1 in 3 people will develop cancer in their lifetime.

Recent estimates suggest the ratio is 1 in 2.

The UK population is 65 640 000.

If the recent estimate is correct, how many people can be expected to develop cancer?

Give your answer to 2 significant figures.

Suggest why the figure calculated in (a)(iii) will be an estimation.

Cancer of the ovaries is a common type of cancer. Most women diagnosed with cancer of the ovaries will have an operation to remove their ovaries.

Before the operation, the doctor will discuss the risks of the operation with the patient. This is a high risk operation.

Suggest why a patient would decide to go ahead with this operation.

After surgery, the patient may have chemotherapy to kill any remaining cancer cells.

Chemotherapy also kills white blood cells.

A doctor describes this effect to the patient.

Draw a line graph on the axes below to show what happens to the number of white blood cells during each cycle of chemotherapy.

During the chemotherapy treatment, the patient is advised to seek urgent medical attention if they become ill and have a raised temperature.

Suggest between which days the patient is most at risk of becoming ill. Use data from the graph in your answer.

Why is a high temperature in the human body a problem?

New drugs and treatments have to go through rigorous clinical trials.

A clinical trial was conducted to see if using a particular combination of chemotherapy drugs increased survival rates for a type of cancer of the ovaries.

The two drug combinations being tested were:

• drugs 1 and 2

• drugs 3 and 4.

The table shows some details of the clinical trial design.

Use your knowledge of clinical trials to justify each part of the design.

Explain why scientists should communicate findings such as these to a range of audiences.

Scientists have been developing the use of monoclonal antibodies in cancer treatment.

Monoclonal antibodies specific to a cancer cell antigen are produced and are injected into the blood of a cancer patient.

Describe how monoclonal antibodies are used to treat cancer.

The female mosquito Aedes aegypti is responsible for the transmission of diseases such as Zika virus.

In May 2015, Zika virus was reported in Brazil and began to spread rapidly.

The mosquito feeds mainly on human blood. The virus is spread when a female Aedes aegypti mosquito bites an infected human and then bites an uninfected human.

Zika virus is a communicable disease.

Visitors to Brazil in 2016 were concerned that they could become infected with the virus.

There is no vaccination for this virus.

Explain what a communicable disease is and suggest how a visitor to Brazil could reduce the risk of becoming infected with Zika.

The first ever human case of Zika was discovered in Nigeria in 1954. The timeline below shows how Zika spread.

1954 1977–78 2007 2013 2015 Nigeria Pakistan, Malaysia, Micronesia French Polynesia Brazil

The Zika virus can also be transmitted by sexual intercourse.

People were concerned that hosting the Olympic games in Brazil in 2016 would increase the spread of the virus to other countries.

Suggest how the virus could be spread to other countries and how this could be prevented.

The mosquito responsible for the spread of Zika has become resistant to some of the insecticides used to kill it.

Explain how a population of mosquitos could have become resistant to an insecticide.

One way scientists tried to solve the problem was to make genetically engineered mosquitoes that had a ‘kill switch’ gene. This gene caused the mosquitoes’ offspring to die.

Describe the steps a scientist would use when genetically engineering a mosquito to have the ‘kill switch’ gene.

The ‘kill switch’ gene codes for the production of a protein called tTAV.

The tTAV protein blocks the transcription of other genes essential for mosquito survival.

When breeding the mosquitos in the laboratory a chemical called tetracycline is used. Tetracycline binds to the tTAV protein and deactivates it.

Suggest why scientists use tetracycline when breeding the genetically engineered mosquitos.

Scientists thought using genetically engineered mosquitos was a better solution than using insecticide.

Do you agree?

Explain your reasons.

A gene affects whether people have dimples in their cheeks. There are different variants of this gene.

An individual with the dominant variant, D, of this gene will have dimples.

Jack and his wife Nina both have dimples.

Their daughter Mia does not have dimples.

Complete the table to show the genotype of each individual.

Jack and Nina decide to have another child.

What is the probability that the second child will have dimples?

Use the Punnett square to show your working.

Scientists consider this trait an ‘irregular’ dominant trait. This is because sometimes a person can have dimples but their children do not.

What could be responsible for this difference?

Amaya reads an article in a magazine which explains that genes code for the production of a taste receptor on the tongue.

Taste receptors are proteins.

Complete the sentences to describe how a protein is made.

Use words from the list.

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

amino acids bases DNA fatty acids gene

genetic variant mitochondrion mRNA protein ribosome

A copy of the........ is made from........

This molecule travels to a........ in the cytoplasm.

Here........ are joined together to form a protein.

A mutation would create a........ and therefore a different receptor.

Scientists think that a mutation created the type of receptor that allows someone to taste a bitter substance.

Explain how a mutation could affect the structure of the receptor protein.