OCR GCSE Combined Science A (Gateway) Biology Paper 8 Higher November 2021 question paper J250/08

The cells in the diagram are important for defence from pathogens in the air.

Which organ of the body are the cells found in?

A Arteries

B Brain

C Lungs

D Small intestine

The graph shows the link between smoking cigarettes and lung cancer.

The average number of cigarettes smoked per person starts to fall in 1975.

How many years later did the number of lung cancer deaths also start to fall?

A 5

B 10

C 15

D 20

Which term describes the interaction between living organisms and their physical environment?

A Community

B Ecosystem

C Habitat

D Trophic level

A flower homozygous dominant for colour is crossed with a homozygous recessive flower.

What is the predicted percentage of heterozygous offspring?

A 25%

B 50%

C 75%

D 100%

Mutualism and parasitism involve two different organisms living together.

Which statement describes the difference between mutualism and parasitism?

A Both organisms benefit from living together in mutualism, only one benefits in parasitism.

B Both organisms benefit from living together in parasitism, neither benefit in mutualism.

C Neither organism benefits from living together in parasitism, both benefit in mutualism.

D One organism benefits from living together in mutualism, both benefit in parasitism.

One method of surgical treatment for cardiovascular disease involves inserting a metal or plastic tube into the coronary artery.

How will this surgical treatment help to improve the condition of a patient who has cardiovascular disease?

A It increases blood flow to the lungs.

B It increases oxygen supply to the heart muscle.

C It prevents blood flow through the damaged artery.

D It prevents oxygenated and deoxygenated blood mixing.

The human genome project mapped the human genome. This gave many benefits and risks.

Which statement is an ethical issue arising from the mapping of the human genome?

A Genes linked to different types of disease are identified and mapped.

B Human migration patterns can be traced to find the origin of our ancestors.

C Someone’s genetic makeup can be used by life insurance companies to predict their risk of future illness.

D Treatments are developed due to understanding of inherited disorders.

White clover plants have two variants.

Cyanogenic variants produce a toxin when their cells are damaged. Acyanogenic variants do not produce a toxin.

The cells of clover plants can be damaged by freezing temperatures or by snails eating the leaves. The toxin kills snails but also damages the plant.

Table 11.1 shows growing regions of the two variants.

Complete the hypothesis to link each variant to the region it is most often found.

Acyanogenic variants are found in colder climates because........

Cyanogenic variants are found in warmer climates because........

To investigate a hypothesis a field study is needed.

Sampling techniques are used to estimate the population size of each variant in different areas.

Why are sampling techniques used instead of counting the total number of individual plants in each area?

Two students investigate the variant plants living at altitudes of 0–250 metres.

The students use random sampling as a starting point of their investigation. They then go on to complete a transect.

Explain how random sampling differs from a transect.

Explain why using a transect would develop and improve their investigation.

Fig. 11.1 shows the number of cyanogenic variant plants found in a total clover population of 200 at different altitudes.

What conclusion can be made about the effect of altitude on the distribution of cyanogenic clover?

Predict the altitude where you would expect to find mostly acyanogenic clover plants. Explain why most clover plants are acyanogenic at that altitude.

Use the theory of natural selection to explain how the cyanogenic variant of white clover plant could have developed.

The flowchart in Fig. 12.1 shows bacteria involved in cycling nitrogen.

Identify which of the bacteria in Fig. 12.1, if present in large amounts, would make the soil poor for plant growth.

Tick (✓) one box.

Explain why large amounts of these bacteria would make the soil poor for plant growth.

Abiotic and biotic factors can affect the bacterial communities.

Which is a biotic factor?

Tick (✓) one box.

Plants are an important part of any community.

Fig. 12.2 shows the effect of abiotic factors on the rate of photosynthesis by plants.

Explain why lines X, Y and Z level out at different rates of photosynthesis.

Describe the relationship between health and disease.

HPV (human papilloma virus) causes cervical warts.

Fig. 13.1 is a diagram representing the size of HPV as it would be seen using an electron

The HPV shown in Fig. 13.1 has a diameter of 50 mm. The actual HPV has a diameter of 55 nanometres.

Calculate the magnification of the HPV shown in Fig. 13.1.

Give your answer to 2 significant figures.

Magnification = ×........

Women can be given a vaccine to protect against HPV.

Explain why the vaccine produces an immune response to HPV but does not cause cervical warts.

Describe two ways scientists test new vaccines to ensure they are safe for humans.

The diagram shows two cells from a mosquito with a chromosome number of 6.

Different types of cell division produced Cell A and Cell B.

Name the type of cell division that produced Cell A and explain its importance for the mosquito.

Type of cell division........

Sexual reproduction is important for species as it results in differences within a species.

Within a species of mosquito there are some mosquito that need blood to lay eggs and others that do not.

Why is this an example of discontinuous variation?

What is the probability of a baby being male when humans sexually reproduce?

Complete the genetic diagram to explain your answer.

The cornea is a part at the front of the eye that allows in light.

The cornea can be damaged by injury or disease. Treatment often requires a local anaesthetic. Local anaesthetics stop nerve impulses passing along the sensory neurone.

Use your knowledge of the structure of a reflex arc to explain why a person would not feel pain.

Pregnancy can affect the response of neurones to local anaesthetics.

The graph shows the effect of a local anaesthetic on nerve activity in women.

Time following local anaesthetic injection (minutes)

Look at the data over the first 10 minutes after injection.

Calculate the percentage decrease in nerve activity after 10 minutes when pregnant compared to not being pregnant.

The data in the graph has range bars plotted. These give the highest and lowest values at each point.

Why is this an improvement when presenting this data?

Explain why stem cells taken from embryos are more suitable than those from adult bone marrow.

* Scientists can use embryo stem cell technology for treating damage to the cornea to restore vision.

Read the information in the box.

• Corneal cells are transparent to allow light to pass through.

• Corneal tissue does not have blood vessels in order to remain transparent.

• Corneal transplants from donor tissue are one way to restore vision after damage to the cornea.

• Corneal transplants are at risk of tissue rejection when blood vessels develop in the cornea.

• Scientists are able to genetically engineer donor corneal cells to prevent new blood vessel formation following transplantation.

• The genetically engineered cells produce a protein which prevents the formation of blood vessels.

Describe the main steps involved in genetically engineering donor corneal cells and identify any improvements and risks from this type of treatment.