Edexcel A Level Biology B Paper 1: Advanced Biochemistry, Microbiology and Genetics June 2024 question paper 9BI0/01

Blood is pumped around the body in blood vessels to supply cells with nutrients and oxygen.

Which box in each row of the table shows where endothelial cells and valves are found?

Nutrients and oxygen pass into cells from tissue fluid.

Explain how tissue fluid is formed.

Glucose is a monosaccharide that is found in sucrose, amylose and amylopectin.

Sucrose is made from glucose and one other molecule.

Which row of the table gives the name of this molecule and the type of reaction that joins the two molecules together?

Compare and contrast the structure of amylose and amylopectin.

Viruses can replicate using the lytic cycle.

Viruses can be grown in a laboratory by culturing them with appropriate cells.

Explain why viruses have to be cultured with ‘appropriate cells’.

The graph shows the changes in the number of viruses after they had been added to the cells.

Time after adding viruses to the cells / min

Explain why the number of viruses did not start to increase until after 20 minutes.

Calculate how many more viruses are present at 70 minutes than at 50 minutes.

Give your answer to three significant figures.

Photosynthesis results in the production of GALP. This molecule is used by plants to produce glucose and other organic molecules.

Glucose consists of the elements of carbon, hydrogen and oxygen.

Name the inorganic molecules that supply these elements for photosynthesis.

Light is essential for photosynthesis. It is needed for photolysis and for the excitation of electrons in the photosystems.

Which row in the table shows where photolysis and the excitation of electrons occurs?

Scientists have developed an experimental technique that uses artificial photosynthesis.

Electricity generated from solar panels was used to convert carbon dioxide and water into the organic compound acetate.

Plants were then able to grow in the dark using the acetate.

Explain why these plants were able to grow in the dark.

The scientists hope that this technique will be able to produce plant‑based food.

State one advantage of using this method.

Give a reason for your answer.

Septicaemia is a life‑threatening condition that can arise from bacterial infection.

In one year, 245 000 people were diagnosed with septicaemia and 49 735 of these people died as a result.

Which percentage of people survived septicaemia in this year?

Two types of bacteria that cause septicaemia are Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).

E. coli is Gram negative and S. aureus is Gram positive.

Which of the following statements about the cell walls of these bacteria are correct?

1. Both bacteria have peptidoglycan (murein) in their cell walls.

2. S. aureus has an outer membrane (lipopolysaccharide layer).

3. The cell wall of E. coli is thinner than that of S. aureus.

Both E. coli and S. aureus produce toxins.

E. coli produces the same type of toxin as Salmonella bacteria.

Which of the following statements about the toxins produced by these bacteria are correct?

1. E. coli produces endotoxins.

2. The toxins produced by S. aureus are released only once the bacteria die.

3. The toxins produced by S. aureus are components of their cell wall.

Vaccines against bacteria are not always effective. The antigens they contain stimulate only a weak immune response.

Which of the following types of immune response is stimulated by a vaccine?

There are currently no vaccines for either E. coli or S. aureus.

Scientists are developing vaccines against E. coli and S. aureus which can be implanted under the skin.

The bacterial antigens are held in a mesh that contains chemicals to attract tissue macrophages.

The effect of implantation of these vaccines on the immune response in mice was investigated.

The graph shows the number of T helper cells in the lymph nodes that drain the part of the body where the vaccine was implanted.

Time after implantation of vaccine / days

Explain the results shown in the graph.

In part of this investigation, mice had the vaccine implanted 35 days before being infected with E. coli.

A control group that had not received the vaccine was also infected with E. coli.

The levels of antibody in the blood of both groups of mice were determined.

The graph shows these results.

Explain the results shown in the graph.

In a cell, DNA is found in both the nucleus and the mitochondria.

Where is DNA found in mitochondria?

Which row of the table describes DNA found in the mitochondria?

Name this type of mutation.

Explain how this mutation could affect the structure of the tRNA^Lys molecule shown in the diagram.

Explain how this mutation could affect the role of the tRNA^Lys molecule.

Coal tits, blue tits and great tits are three species of bird found in the UK all year round.

The photograph shows a blue tit.

These birds all have mitochondria in their red blood cells.

More than 90% of ATP is produced by mitochondrial respiration.

Describe how the remaining ATP is produced.

In the mitochondria, ATP is synthesised on the inner mitochondrial membrane.

Leakage of protons (H⁺) across the inner mitochondrial membrane reduces ATP synthesis and generates more heat. This is called leaked respiration.

Explain why leakage of protons reduces ATP synthesis.

The table shows some information about adult coal tits, blue tits and great tits.

Calculate the magnification of the photograph of the blue tit.

Measure from the top of the head to the tip of the tail.

Calculate the length from head to tail: mass ratio for the great tit.

Give your answer to one decimal place.

The generation of heat by red blood cell mitochondria in these birds in autumn and winter was investigated.

The mean air temperature in autumn was 10.7 °C and in winter 7.2 °C.

The flowchart shows some of the stages in this investigation.

Bird feeders containing nuts were set up and refilled each day

Birds were caught daily in a two-week period in both autumn and winter. They were ringed, measured and a blood sample taken before they were released

Samples of intact red blood cells and red blood cell mitochondria were separated from the blood

Leaked respiration and the volume of mitochondria were measured

Explain why well‑stocked bird feeders containing nuts were available throughout this investigation.

Changes must occur to mammalian sperm cells as they pass through the female reproductive tract, if successful fertilisation is to take place.

Capacitation results in changes to the sperm cell membrane and increased motility.

The acrosome reaction (AR) must follow capacitation but not too soon nor too late.

Explain why the timing of the AR is important for successful fertilisation.

A protein is involved in the timings of capacitation and the AR.

This protein exists in two forms: protein G and protein G‑P.

Protein G‑P results in the stimulation of capacitation and protein G results in the inhibition of the AR.

Protein G‑P is located in the midpiece (neck) and flagellum of the sperm.

Protein G is located in the head region of the sperm.

The levels of these two forms of protein change just before capacitation, during capacitation and just before the AR.

Complete the table to show which form of protein is present and which is absent.

If the protein is present put a tick () in the box and if the protein is absent put a cross (✗) in the box.

In some infertile males, the gene coding for protein G is methylated.

Explain why DNA‑methylation of this gene could result in infertility.

Scientists have used ‘knockout’ mice to investigate the effect of protein G on fertility.

State the meaning of the term ‘knockout’ mice, as used in this context.

In an investigation, female mice and ‘knockout’ mice were housed together.

Describe how this investigation should be designed to confirm that protein G affects fertility.

The structure of haemoglobin changes as the embryo develops into a fetus and after the child is born.

The graph shows the changes in the synthesis of four globin subunits (beta, gamma, delta, epsilon) during these stages of development.

Explain why there is no synthesis of globin subunits in the first few days after fertilisation.

Analyse the data to describe conclusions that can be made about globin subunit synthesis during the 14 months following fertilisation.

Calculate the rate of decrease in percentage of gamma globin subunit synthesis from 7.6 to 10 months after fertilisation.

Give your answer to two decimal places with appropriate units.

Sickle cell disease (SCD) is an inherited disorder.

A new treatment for SCD is being developed that involves genetic modification.

The flowchart shows some of the stages in this process.

Bone marrow stem cells removed from patient

Stem cells genetically modified by turning the BCL11A gene off

Genetically modified stem cells injected back into the same patient

There are approximately 67 million people in the UK, 15 000 of these people are affected by SCD.

Calculate the ratio of the number of people without SCD to the number of people with SCD in the UK.

Express your answer in whole numbers.

*(ii) The product of the BCL11A gene regulates the switch from the synthesis of fetal to adult globin subunits.

Analyse all the information in this question to discuss how this approach could provide a cure for SCD and the ethical issues surrounding this treatment.

Use your own knowledge to support your answer.