OCR GCSE Biology B (21st Century) Breadth in Biology Higher November 2021 question paper J257/03

Plants and animals use small organic molecules to make larger organic molecules.

Draw lines to connect the small organic molecules with the large organic molecules that they are used to make.

Small organic molecules
Large organic molecules

Plants obtain important substances from their environment.

Which list of elements must plants obtain from the environment?

Tick (✓) one box.

Tay-Sachs disease is an inherited disease caused by a recessive allele.

The symptoms of the disease start when a child is 3–6 months old. The disease is usually fatal.

Charlie and Eve decide they want to have a child. They do not have the disease, but they are concerned that they may be carriers of this disease and will pass it on to their child.

Describe how Charlie and Eve could find out if they are carriers.

Charlie and Eve find out they both have the genotype Tt.

What word is used to describe this genotype?

Charlie and Eve still want to have a child.

Complete the Punnett square to find out the probability of their child having Tay-Sachs

Charlie and Eve decide that they do not want to risk their child inheriting Tay-Sachs disease.

Suggest two ways in which they can have a child that does not have the disease.

The diagram shows a pyramid of biomass for the following food chain.

Food chain

Pyramid of biomass Dry weight (g / m²)

Which organism in the food chain would you place in bar A of the pyramid of biomass?

Describe the general change in biomass that occurs between the trophic levels shown in the pyramid and give two reasons for this change.

The percentage efficiency of the biomass transfer between trophic levels can be calculated using the efficiency equation:

Calculate the percentage efficiency of the biomass transfer between trophic levels 2 and 3.

Give your answer to 1 significant figure.

This question is about hormones in plants and animals.

Select the correct word from the list to match each statement.

You can use each word once, more than once, or not at all.

ADH adrenalin auxin ethene FSH gibberellin

LH oestrogen progesterone thyroxine

A plant hormone responsible for the ripening of fruits........

A plant hormone responsible for gravitropism in roots........

A human hormone that is responsible for ovulation........

A human hormone that increases the permeability of the

kidney tubule........

A human hormone that regulates growth and chemical

reactions in cells........

A human hormone used in the contraceptive pill to

prevent ovulation........

DNA is found in both eukaryotic cells and prokaryotic cells.

Explain the difference in how DNA is stored in these two types of cells.

Describe the structure of DNA.

A student talks about DNA with their friend.

The student tells their friend that all features in a person’s phenotype are controlled by single genes in their DNA.

Give one reason why the student is wrong.

Flystrike is a condition that affects sheep in the UK and New Zealand.

Blowflies are attracted to the smell of urine on the fleece (wool) around the sheep’s backside, as shown in the diagram. They lay their eggs and when the eggs hatch, maggots are released. The maggots bury deep into the sheep’s flesh and feed on it as a food source.

Sheep that are most at risk have long fleece.

Scientists in New Zealand selectively breed sheep to prevent this problem.

Table 6.1 gives information on different breeds of sheep and their features.

Select two breeds of sheep from Table 6.1 that the scientists could use in the selective breeding programme to prevent flystrike, and give one reason for your selection.

Breeds of sheep:

Describe how the scientists would use selective breeding to produce sheep that are less likely to get flystrike.

Sheep and other species produce milk. Milk contains protein, sugar and fat.

Table 6.2 shows the percentage of sugar found in the milk from some mammals.

Describe how Benedict’s reagent could be used to show that the amount of sugar in the milk of different species varies, and how the results would support the data in Table 6.2

Name the reagent that would test for the presence of protein.

The picture shows an animal called a Tasmanian devil. These animals are only found on an island off the coast of Australia.

The table shows data for the estimated population of Tasmanian devils from 1995 to 2008.

Plot a bar chart to represent the data shown in the table.

Calculate the percentage decrease in the estimated population of Tasmanian devils between 1995 and 2008.

Give your answer to 3 significant figures.

The decrease in population is because of a disease called Devil Facial Tumour disease.

Devil Facial Tumour is a form of cancer. It is spread from one Tasmanian devil to another when they bite each other.

How is the Devil Facial Tumour cancer different from cancers found in humans?

Scientists have discovered six disease-resistant Tasmanian devils in the population.

Initially scientists did not know if this resistance was hereditary.

Suggest how the scientists could investigate whether the resistance could be inherited.

The Colorado potato beetle feeds on potato crops.

Farmers can use different chemical compounds to kill the beetle. The beetle has developed resistance to these chemicals over time.

The graph shows the cumulative number of chemicals that Colorado potato beetles have become resistant to, from 1955 to 2003.

Explain why farmers are worried about the effect that Colorado potato beetles may have on potato crops in the future.

Use data from the graph to support your answer.

Using insecticides is one method of controlling insect pests.

Suggest one alternative method that could be used to control insect pests.

The evolution of new pests is one example of a biological threat to food security.

Identify two additional threats to food security.

Explain two ways in which white blood cells defend against disease.

Multiple sclerosis is a disease which causes the fatty sheath surrounding neurons to break down.

What is the role of the fatty sheath?

Information about the clinical trial is given in Fig. 9.2.

Multiple sclerosis (MS) clinical trial

• 24 patients were involved

• All patients had advanced MS

• Results showed that 70% of patients showed no sign of the disease after treatment

• One patient died during the study as a result of the treatment

Fig. 9.2

This was the first clinical trial of this treatment and it was not known what effects the treatment would have.

Suggest why the patients still chose to take part in the trial, even though there were risks.

The results of this study were published in a peer reviewed journal.

Why would this give other scientists confidence in the findings?

24 patients took part in this study. Only half of the patients were reassessed after 3 years.

Why is this a concern?

Reactions catalysed by enzymes are affected by temperature changes.

Describe how body temperature affects the rate of reactions catalysed by enzymes.

The graph shows the effect of temperature on the rate of reaction for the enzyme catalase.

The table shows the optimum temperature for catalase in three different organisms.

Which organism from the table was used to produce the data shown in the graph?

Explain your answer.

Gonorrhoea is a sexually transmitted disease.

The number of recorded cases in England from 2008 to 2015 is shown in the table.

Describe the trend shown by the data and suggest one possible reason for this trend.

A group of students discuss the treatments available for gonorrhoea.

Suggest why scientists are concerned about gonorrhoea.

Use information from the students’ discussion to support your answer.

The drugs currently in development are being tested in clinical trials. They are being tested on healthy people and on people with the disease.

Explain why the drugs are being tested on both groups of people.

Insulin and glucagon are two hormones involved in the control of blood sugar in humans.

The statements explain how insulin and glucagon work together to control blood sugar.

Complete the table by deciding if each statement explains the role of insulin, glucagon or both.

Tick (✓) one box for each statement.

A student is looking at some pancreas cells using a microscope. They draw one of the cells.

The actual size of this cell from points A to B is 80 µm.

Calculate the magnification used to produce this drawing.

Magnification = ×........

The magnification of a light microscope is 1.5 × 10³.

The magnification of an electron microscope is 5 × 10⁵.

Calculate the difference in magnification.

Give your answer in standard form.

This question is about photosynthesis.

Write the balanced symbol equation for photosynthesis.

A student investigates the effect of light intensity on the rate of photosynthesis.

They set up a test tube containing pond weed in water at different distances from a lamp.

Their results are shown in the table.

The student writes down the relationship between light intensity and the distance, d, of the pond weed from the lamp.

Explain why the rate of photosynthesis was lower at 20 cm than at 10 cm.

Use the inverse square law and data from the table to support your answer.

The graph shows how different factors affect the rate of photosynthesis.

Which factors are limiting the rate of photosynthesis at points A, B and C ?

Explain your answers.

Limiting factor at point A........

Limiting factor at point B........

Limiting factor at point C........

A........

B........

C........