Extended Response (A Level Only) (AQA A Level Biology)

Exam Questions

3 hours10 questions
1a5 marks

Plants produce ATP in two ways: photosynthesis and respiration. Explain why it is necessary for plants to produce ATP during respiration as well as during photosynthesis.

1b6 marks

Describe the role of electron carrier proteins and the electron transport chain (ETC) in the light-dependent reactions of photosynthesis.

1c4 marks

Predict whether the increase in dry mass of a plant over 15 months will be greater or less than the mass of hexose sugars produced during the same time period. Justify your answer.

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2a6 marks

Describe and explain the role of the loop of Henle in osmoregulation, specifically the absorption of water from the glomerular filtrate.

2b5 marks

Describe and explain the role of ADH in urine production.

2c4 marks

Some diabetic individuals do not produce insulin. Explain how an inability to produce insulin would affect the reabsorption of glucose within the kidneys.

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3a6 marks

Describe the mechanism by which a heartbeat is initiated and coordinated.

3b4 marks

Exercise causes an elevated heart rate. Describe the role of nervous system and receptors in causing an increased heart rate.

3c5 marks

Explain how a one-way flow of blood from the left atrium to the aorta is maintained.

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4a5 marks

Describe the role of ATP and calcium ions during the mechanism of muscle contraction.

4b4 marks

Mucus produced by epithelial cells within the human gas exchange contains glycoproteins. One of the glycoproteins is a modified polypeptide that has the sugar lactose attached to it.

Describe how the sugar lactose is formed and location within the cell where the polypeptide is attached to lactose to form a glycoprotein.

4c6 marks

Describe the anatomy of the human gas exchange system and the mechanism of inhalation and exhalation.

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5a6 marks

Biologists were carrying out research on several small islands off the coast of Papua New Guinea. They discovered that there are over 20 species of frogs belonging to the same genus on the islands. They believe that these species evolved from two ancestral species found on mainland Papua New Guinea. Explain how the island frog species could have evolved.

5b5 marks

A lot of the frog species on the islands have a similar appearance. The biologists must see the frogs in close detail in order to identify what species they are. Describe how the mark-release-recapture method could be used to estimate the number of a particular frog species on one of these islands.

5c4 marks

The biologists were also studying the different plant species present on all the islands. One of the biologists stated that they thought succession had occurred on two of the Islands. Succession can occur naturally in ecosystems. Describe and explain how it occurs.

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6a5 marks

DNA replication must be very accurate to ensure normal growth and development of organisms. Describe and explain how the structure of DNA results in a high level of accuracy during replication.

6b6 marks

The process of meiosis begins with the chromosomes condensing. Describe what happens to the chromosomes next.

6c4 marks

Meiosis results in genetic variation in gametes. This leads to variation in the offspring formed by sexual reproduction. Explain why this variation is advantageous for a species.

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7a4 marks

When food passes to the small intestine, starch molecules are broken down to maltose by pancreatic amylase. This process takes place at normal body temperature.

Explain why amylase only breaks down starch and why amylase allows this reaction to take place at normal body temperature.

7b6 marks

Amylase is an enzyme that can break down starch into maltose. Biologists have investigated how competitive and non-competitive inhibitors affect amylase.

Describe competitive and non-competitive inhibition of enzymes.

7c5 marks

Once amylase has broken starch down into maltose, maltase can then break maltose down into glucose. 

Describe how glucose is then absorbed so it can be used by the body.

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8a6 marks

Some white blood cells are known as phagocytes. Describe how these cells destroy bacteria.

8b5 marks

Contrast active and passive immunity.

8c4 marks

Vaccines designed to protect people from Covid-19 are currently being developed by many different scientific research laboratories around the world.

Explain how vaccines can protect humans from disease-causing organisms

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9a6 marks

Starch and cellulose are both polysaccharides made up of many glucose molecules.However, they both have different structures and functions. Describe and explain how the structures of starch and cellulose molecules relate to their functions.

9b5 marks

Plants have to transport substances, such as water and sugars, along their stems. Describe how sugars are transported in plant stems.

9c4 marks

The cohesion-tension theory explains how water is transported in the xylem. Describe this theory.

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10a6 marks

Give similarities and differences (stating at least two of each) between the DNA in a eukaryotic cell and the DNA in a prokaryotic cell.

10b5 marks

Describe the production of mRNA in an animal cell.

10c4 marks

The mRNA in part (b) can now be used to form a polypeptide via a process known as translation. Describe how this occurs.

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