Edexcel A Level Biology B Paper 1: Advanced Biochemistry, Microbiology and Genetics June 2023 question paper 9BI0/01

Plants take up inorganic ions from the soil.

These ions include calcium, phosphate and potassium.

Name the molecule that contains calcium ions in the cell walls of a plant.

How many of the following statements are correct?

• phosphate ions are used to make DNA and RNA

• phosphate ions are used in the structure of the cell membrane

• the element potassium is part of a peptide bond

Living organisms are divided into three domains: Archaea, Bacteria and Eukaryota.

The table shows some characteristics of organisms in the domain Archaea.

Explain why these organisms have not been classified in either of the other two domains.

Some Archaea have the enzyme adenylate kinase (AK).

This enzyme is similar to AK enzymes found in humans.

There are two types of this enzyme in humans, AK1 and AK3.

The table gives some information about these two enzymes.

The tertiary structures of AK1 and AK3 are very similar but not identical.

Analyse the information to deduce why there are two AK enzymes.

Some types of Archaea have only one type of AK enzyme.

This enzyme can catalyse both the reactions shown in the table.

The tertiary structure of this enzyme is different from AK1 and AK3.

Explain why Archaea have a different type of AK enzyme.

Xylem and phloem tissues transport molecules and ions through plants.

Give the meaning of the term tissue.

The table gives some information about the structures of xylem and phloem tissues.

whether these statements are true for both types of tissue, xylem tissue only, phloem tissue only or neither type of tissue.

Aphids are insects that can be used to study the transport of sugars in the phloem.

The diagram shows how this is done.

Which disaccharide is transported in the phloem?

In an experiment, the time between radioactivity appearing in aphid A and aphid D was 210 minutes.

The distance between these two aphids was 50 cm.

Calculate the rate of flow of phloem contents between these two aphids, in cm hour^–1.

Describe how sugars are transported through the phloem.

Influenza is an infectious disease caused by a virus.

The influenza virus is an RNA virus and has an envelope.

Which pair of viruses also have RNA and an envelope?

Which of the following is the predominant method of transmission of the influenza virus?

Symptoms of influenza appear some time after a person is infected with the virus.

Explain why there is a time delay between infection and the symptoms appearing.

In some countries, people take antibiotics without a prescription.

In a survey, 77% of people who had taken antibiotics had taken them without a prescription.

Some of the people who took antibiotics without a prescription had influenza.

Calculate the ratio of the number of people who took antibiotics without a prescription to the number of people who took antibiotics with a prescription.

Give your answer to two decimal places.

Explain why antibiotics should not be taken by people with viral infections.

Some forms of infertility are due to the female producing antibodies to sperm cells.

Contraceptives are being developed that use these antibodies.

Antibodies can be injected into a person to give immunity.

Which type of immunity develops from the injection of antibodies?

In the development of these contraceptives, an agglutination assay was performed.

Antibodies were mixed with sperm cells and the time taken for 100% of the sperm cells to agglutinate was recorded.

Different concentrations of antibody were tested.

The number of sperm cells that escaped from the sperm cell agglutinates, at each concentration of antibody, was also recorded.

Each test used 2 µ l of a sperm cell suspension at a concentration of 3.0×10⁶ cells per cm³.

1µl = 10^–6dm³

Calculate the number of sperm cells used in each test.

The graphs show the results of this assay.

Analyse the data to comment on these results.

Observation of the sperm cells agglutinated by these antibodies showed that some were joined head to head, some head to flagellum and some flagellum to flagellum.

Explain these observations.

In the development of these contraceptives, the effect of the concentration of sperm cells on the time taken to agglutinate was also investigated.

Explain why agglutination could take longer at low and at high concentrations of sperm cells.

Scientists have removed thylakoids from chloroplasts to make artificial chloroplasts.

The diagram shows part of a chloroplast.

Draw and label three other structures found in a chloroplast.

Chloroplasts can be 3 µ m in length.

Calculate the magnification of this diagram for a chloroplast that is 3 µ m in length.

Give your answer to two significant figures.

Explain the importance of the thylakoid membranes in the light‑dependent stage of photosynthesis.

The artificial chloroplasts made by the scientists consisted of thylakoids removed from spinach leaves, and enzymes involved in carbon fixation.

These components were put into water, forming a suspension.

This suspension was dropped into a medium containing oil.

The suspension formed cell‑sized droplets of water containing the thylakoids and the enzymes.

Name the enzyme that fixes carbon dioxide in the light‑independent stage of photosynthesis.

Explain why it is necessary to keep the thylakoids and enzymes together within droplets.

The Yap Trench is an area of very deep water in the Pacific Ocean.

In 2017, a new species of fish was caught in the Yap Trench. This was named the Yap hadal snailfish.

The photograph shows a different species of snailfish, the Mariana hadal snailfish.

(Source: © Adisha Pramod/Alamy Stock Photo)

The Yap hadal snailfish was caught in a deep sea trench, at a depth of 7 000 m below sea level.

Hydrostatic pressure increases 100 kPa with every 10 m of depth.

Calculate the hydrostatic pressure at 7 000 m.

Give your answer in standard form.

Analysis of the genome of the Yap hadal snailfish and the Mariana hadal snailfish showed that they were closely related.

The DNA from the Yap hadal snailfish contained 725 608 564 bases and 204 202 736 of these bases were adenines.

Calculate the number of guanine bases in the DNA of this fish.

The Venn diagram shows unique and shared gene families in the genomes of three species of snailfish and a zebrafish.

Calculate the percentage of gene families in the Yap hadal snailfish that are shared with the Mariana hadal snailfish.

Give your answer to one decimal place.

The diagram shows the evolutionary relationship between three species of snailfish and a zebrafish.

Analyse the diagram to describe the evolutionary relationship between these four species of fish.

*(iv) The Mariana hadal snailfish and the Yap hadal snailfish were caught in separate trenches hundreds of kilometres apart.

Explain how these fish evolved to become separate species.

Vaccines are being developed to stimulate the immune response to destroy cancer cells.

Some of these vaccines contain mRNA that codes for specific antigens found on cancer cells.

These vaccines deliver the mRNA into antigen presenting cells, such as macrophages.

Describe how the delivery of mRNA into macrophages results in antigen presentation by these cells.

Antigen presentation results in the stimulation of both the humoral immune response and the cell‑mediated immune response.

Compare and contrast the humoral immune response with the cell‑mediated immune response.

These vaccines stimulate both the humoral immune response and the cell‑mediated immune response.

Explain how the products of these responses result in the destruction of cancer cells.

The photograph shows a shortfin molly.

(Source: © WILDLIFE GmbH/Alamy Stock Photo)

This fish has adapted to survive in environments where levels of hydrogen sulfide (H₂S) are toxic to other organisms.

Hydrogen sulfide can interrupt mitochondrial respiration by inactivating cytochrome c oxidase, one of the proteins in the electron transport chain.

Where is the electron transport chain located in mitochondria?

Explain why inactivating cytochrome c oxidase could be fatal.

The adaptation of these fish to H₂S in their environment is thought to be due to epigenetic modification by DNA methylation.

State the meaning of the term epigenetic modification.

Which of the following is another type of epigenetic modification?