AQA A-Level Biology Paper 2 Predicted Paper 2023 QUESTIONS AND ANSWERS

AQA

A-Level Biology 

Paper 2

Predicted Paper 2023

Name ……………………………………………………………………

Date …………………

2 hours allowed.

You may use a scientific calculator and a ruler with millimetre measurements.

Grade boundaries

These are VERY rough guesses! Getting a B on this paper does not guarantee you the same mark in the exam.

• A* 65%

• A 55%

• B 45%

• C 40%

• D 35%

• E 30%

01

The image below shows a transmission electron micrograph of a longitudinal section of skeletal muscle viewed at x40 000 magnification.

a) Name structures T, U and V.

[3 marks]

T:

U:

V:

b) What is the name of the structure between points V and W?

[1 mark]

c) Explain what causes the banding pattern seen.

[2 marks]

d) Glycogen granules can be seen labelled in the image.

In which type of muscle fibre would you expect to find high concentrations of glycogen granules?

Explain your answer.

[2 marks]

e) During a contraction, muscle fibres shorten on average by around 28%.

Estimate the distance between points V and W in µm if this muscle was contracted.

[3 marks]

f) Some toxins and venoms produced by predators prevent muscle contraction, paralysing their prey. The molecular structure of a kind of snake venom is very similar to the molecular structure of acetylcholine.

Explain how this venom could prevent muscle contraction.

[2 marks]

02

Farmers often use inorganic fertilisers on their fields to increase the amount of nutrients available to growing crops. These fertilisers contain a mixture of nitrates and phosphates.

a) Describe the molecular processes that require phosphates in a growing plant.

[4 marks]

b) Explain why it is important for a farmer to try and reduce the possibility of these fertilisers running off the fields.

[2 marks]

Arbuscular Mycorrhizal Fungi (AMF) grow on and into the roots of plants forming a natural association. They can support plants in low nutrient soils to obtain more inorganic ions including phosphate.

c) Suggest one way in which the AMF may benefit from the plants they grow on in this relationship.

[1 mark]

d) Some scientists wanted to investigate the benefits of AMF on increased biomass of plants in low nutrient soils.

They took samples of soil from low nutrient fields and soil from a fertilised (high nutrient) field. They filled pots with these soils and grew some lettuce with two different species of AMF. In each of the experiments they also added a control group soil.

Their results after leaving the plants to grow for 8 weeks can be seen in the graph below.

i. Suggest what the scientists would have done to create the control pots?

[1 mark]

ii. Explain why the shoots were dried before they were weighed.

[1 mark]

iii. Explain why shoot biomass increase can be used to demonstrate net primary productivity.

[2 marks]

iv. Using the graph, evaluate the effect of adding the AMF species on plant growth in the different soils.