Paper 3, Higher

Explain why muscle cells contain many mitochondria.

Convert 0.025 mm into micrometres and explain why micrometres are used for cells.

Explain why the stomach contains hydrochloric acid.

Explain why heart rate and breathing rate increase during exercise.

Explain why greenhouse growers increase carbon dioxide concentration and temperature.

Calculate the surface area to volume ratio of a cube of side 3 cm.

Explain why plant meristem tissue is useful for cloning plants.

Which blood component helps blood to clot?

Explain how temperature, humidity and wind affect the rate of transpiration.

Explain the cause of short-sightedness and how it is corrected.

Explain how thyroxine is controlled by negative feedback.

Explain why bacterial cells can divide very rapidly and calculate how many bacteria there will be after 2 hours if one cell divides every 20 minutes.

Explain the difference between magnification and resolution.

Explain why different enzymes are needed to digest starch and protein.

State two uses of anaerobic respiration in yeast by humans.

In which part of a leaf cell does photosynthesis happen?

Which process moves water across a partially permeable membrane?

Explain what is meant by cell differentiation.

Describe the structure of the heart and explain how it pumps blood around the body.

Describe the function of three tissues in a leaf.

Explain why the brain is difficult to study and treat.

Describe how IVF treatment is carried out.

Describe how to prepare an uncontaminated culture of bacteria on an agar plate.

A mitochondrion is 2 μm long. Write this in metres in standard form.

Describe a method to investigate the effect of sugar concentration on osmosis in potato tissue.

Explain how red blood cells are adapted to carry oxygen.

Explain why plants need nitrate and magnesium ions.

Which part of the eye controls the amount of light entering?

Explain the role of glucagon in controlling blood glucose.

A clear zone around an antibiotic disc has a diameter of 12 mm. Another antibiotic gives a clear zone of diameter 6 mm. Calculate the area of the larger clear zone and state which antibiotic is more effective.

Explain why single-celled organisms do not need a transport system but large multicellular organisms do.

Explain how faulty heart valves affect a person and one treatment.

What is the function of the cell wall in a plant cell?

Which structure is found in plant cells but not animal cells?