OCR GCSE Biology A (Gateway) Paper 4 Higher June 2024 question paper J247/04

Which row shows correct abiotic and biotic factors?

Which process can make new alleles?

A Evolution

B Mutation

C Selective breeding

D Specialisation

All the living organisms and the place where they live is called …

A A community

B A habitat

C A population

D An ecosystem

Which processes in the carbon cycle return carbon to the atmosphere?

A Decomposition and photosynthesis

B Decomposition and respiration

C Photosynthesis and fossilisation

D Respiration and fossilisation

The diagram shows a labelled plant cell.

Which part of the plant cell gives physical protection against disease?

The graph shows the changes in chromosome number in a cell during meiosis.

What is the diploid number of chromosomes for this cell?

A 2

B 4

C 6

D 8

A gene controlling a characteristic has two possible alleles, A and a. A is the dominant allele.

One person is Aa and another person is AA for this gene.

Which statement correctly describes both people?

A They have different genomes but the same genotype.

B They have different phenotypes but the same genotype for this characteristic.

C They have the same genome but different genotypes.

D They have the same phenotype but different genotypes for this characteristic.

What is the advantage of sampling using a transect line rather than using random sampling?

A A transect allows changes in the size of populations over time to be seen.

B A transect allows patterns in the distribution of organisms to be seen.

C A transect avoids areas which may contain few organisms.

D A transect gives a more accurate estimate of the population.

The diagram shows the results of two different crosses of rats.

Which is a possible explanation of the results of these crosses?

A Grey is dominant. Rat 2 is heterozygous.

B Grey is dominant. Rat 2 is homozygous dominant.

C White is dominant. Rat 1 is homozygous dominant.

D White is dominant. Rat 2 is heterozygous.

All types of white blood cell contain a nucleus.

Which function of white blood cells does not require a nucleus?

A Changing shape to squeeze out of capillaries

B Dividing by mitosis after detecting a pathogen

C Producing antibodies which are made of proteins

D Producing enzymes to digest pathogens

Bacteria can be genetically engineered to make human insulin.

The diagrams show four stages in this process.

What is the order of these processes in insulin production?

A P, S, Q, R

B R, Q, P, S

C R, Q, S, P

D S, P, Q, R

Why are the different structures of these limbs evidence for evolution?

Human arm Cat leg Bat wing Whale flipper

A Differences in the limb bones show that humans, cats and bats evolved from whales.

B Evolution is a random process producing similar structures for different functions.

C The limbs have a similar structure as the organisms all shared a common ancestor.

D The limbs have all evolved from a common ancestor to perform the same function.

The diagram shows how lymphocytes in the immune system respond to antigens.

What is the function of cell X ?

A Cell X will live for many years and engulf foreign bacteria and viruses.

B Cell X will produce antibodies that will destroy plasma cells.

C Cell X will respond rapidly if the antigen reinfects the body again.

D Cell X will respond to antigens from different pathogens.

How many secondary consumers are in this food web?

Mongooses are described as both predators and competitors of St Lucia racers.

Explain why.

Biomass is lost as it passes through this food web.

egestion growth photosynthesis respiration

Mongooses were introduced into St Lucia by farmers to control pests in their fields.

Which term describes this type of pest control?

Tick (✓) one box.

The mongooses soon spread throughout St Lucia.

• Female mongooses can breed 3 times each year and produce 3 babies each time.

• The St Lucia racer lays about 5 eggs each year.

Explain why the mongooses almost made the snake extinct.

By 1973 the St Lucia racers were thought to be extinct but a small number were found on a small island off the coast of St Lucia.

There was a plan to build a bridge to allow tourists to visit the island.

Suggest why these snakes have survived on the island.

Suggest why scientists are against the plan to build the bridge.

Antibiotics and antiseptics are both used to kill bacteria.

Which is a correct statement about antiseptics and antibiotics?

Tick (✓) one box.

Disinfectants also kill bacteria.

Some students do an experiment to see how well four different disinfectants (A, B, C and D) kill bacteria.

This is the method they use:

• Mix 2 cm³ of each disinfectant solution with liquid nutrient agar.

• Pour each of the mixtures into separate Petri dishes and allow to set.

• Spread bacteria on the surface of the agar.

• Put each Petri dish in an incubator.

Describe how the students should spread bacteria on the surface of the agar.

The students’ teacher told them not to seal the lid on the Petri dishes all the way round with tape.

Explain why.

The diagrams show the Petri dishes after 3 days.

Explain two conclusions the students can make about disinfectants B, C and D from these results.

One of the students said that disinfectant A is equally effective at killing bacteria as disinfectant B.

Explain how the students could improve their experiment to test if that is true.

In many areas, the number of elephants living in Africa is decreasing. They are often killed by hunters.

The table shows how the number of elephants in Africa has changed.

Calculate the percentage decrease in the population size between 1979 and 2015.

Give your answer to 2 significant figures.

What is the best description for how the population of elephants changed between 1979 and 2015?

Tick (✓) one box.

In some areas of southern Africa, elephants are very important for ecotourism.

Explain what is meant by the term ecotourism.

In ecotourism areas, elephant numbers are increasing.

This is causing problems as the elephants are eating crops.

Scientists therefore want to control the population size.

They have used three main ways to do this:

• Culling – a certain number of elephants from each population are killed.

• Relocation – elephants are moved to a country where their numbers have dropped.

• Contraception – female elephants are treated to reduce their fertility.

Suggest one disadvantage for each of these methods.

Culling........

Relocation........

Contraception........

Scientists are using a new method of contraception to try and restrict the numbers of elephants.

This involves injecting antibodies which block the sperm receptor sites on eggs.

Describe one way that this method is different to the contraceptive pill used by female humans.

* In East Africa, elephants are hunted for their tusks.

Scientists have found that:

• occasionally female elephants are born without tusks,

• the absence of tusks is caused by a mutated dominant allele,

• the allele for an absence of tusks is lethal if inherited by a male embryo.

Explain why the number of tuskless elephants is rapidly increasing in East Africa.

Explain also why the spread of this allele may have negative effects on the elephant population.

Mistletoe is a green plant that is often seen growing high in a tree in winter.

Mistletoe can photosynthesise, but not at a very fast rate.

It therefore needs to act as a parasite on the tree.

competitor host mutualistic partner prey

Explain why the mistletoe grows into the phloem of the tree.

Scientists investigate two different species of mistletoe growing on a tree. One species of mistletoe has greener leaves than the other.

They give the tree carbon dioxide which contains radioactive carbon.

The carbon dioxide is not supplied to the mistletoe.

They then measure:

• the chlorophyll content of the mistletoe plants,

• the percentage of sugar that is radioactive in each type of mistletoe.

The table shows their results.

Explain why sugar in the mistletoe becomes radioactive.

Explain the relationship between the chlorophyll content and the percentage of radioactive sugar in each species of mistletoe.

Bacteria are found in milk.

They can cause the milk to decompose.

Enzymes from the bacteria convert sugar in the milk into lactic acid.

Some students investigate the effect of temperature on the decomposition of milk.

This is the method the students use:

• Pour 20 cm³ of milk into 3 different beakers.

• Keep each beaker in a water bath at a different temperature: 15 °C, 25 °C and 35 °C.

• Measure the pH of the milk at different times over 4 days.

The table shows their results.

Explain why the students measured the pH of the milk.

Describe how the students should display their results in a graph.

Explain the effect of increasing the temperature on the decomposition of the milk in the experiment.

The students plan a further experiment where they boil the milk first before placing it in the beaker.

Predict what effect this would have on the results.

Explain your answer.

Prediction........

Explanation........

Acrylamide is a chemical that is formed when bread is toasted.

Experiments have shown that significant doses of acrylamide can cause cancer in animals.

Describe the effects of cancer on cells.

Some scientists concluded that, ‘acrylamide could also cause cancer in humans’.

Other scientists are not sure about the effect of acrylamide on humans, despite the results of the animal experiments.

Suggest one reason why.

Give two conclusions that the scientists could make from their investigation.

The daily recommended maximum intake for acrylamide is 195 mg.

A slice of toast has a mass of 50 g.

A person eats toast that is dark and made from potato bread.

Calculate the maximum number of whole slices of toast the person can eat without exceeding the recommended maximum intake.

Use the graph.

Give one reason why another group of scientists would find it difficult to replicate the experiment using just the information in the graph.

During toasting, acrylamide is made from a chemical called asparagine.

Asparagine is produced in plant cells by an enzyme called asparagine synthetase.

The gene coding for asparagine synthetase needs to be switched on by other proteins.

Complete these sentences about how genes are expressed.

Use words from the list.

coding DNA
denaturing
non-coding DNA

nucleus ribosomes transcription

translation tRNA

Gene expression can be switched on by the action of other proteins on........

When a gene is expressed,........ occurs which makes mRNA.

The mRNA then moves to the........

Proteins, such as asparagine synthetase are then made by the process of........

Scientists want to produce a variety of wheat that contains less asparagine.

This is done by preventing expression of the gene that codes for asparagine synthetase.

Describe the difference between this process and genetic engineering.

The table shows some details of three genetic diseases that can affect humans.

There are 66 million people in the UK.

Calculate the number of cases of Huntington’s disease in the UK.

All three diseases affect proteins in different parts of the body.

Explain why each of these diseases cause difficulty in moving the legs.

Huntington’s........

MD........

SMA........

Suggest why the mutation that causes Huntington’s is dominant but the mutation that causes MD and SMA is recessive.

Use the information in the effect column of the table.

Scientists are trying to develop treatments for Huntington’s using stem cells to replace cells damaged by the protein.

Describe two risks of using stem cells to treat patients.