Master GCSE Biology

Questions:

Q1 (2 marks)

Define the term "aseptic technique" used in microbiology, and explain how it is used to reduce contamination.

Q2 (3 marks)

Describe how to use a light microscope to examine a sample of pond water. Include the correct use of a stage micrometer to calculate the magnification.

Q3 (3 marks)

Investigate the effect of light intensity on the growth of cress seedlings. Explain your choice of control variables for this experiment.

Q4 (2 marks)

Describe the technique used to test for the presence of reducing sugars in a solution. State the purpose of using a water bath in this test.

Q5 (2 marks)

Explain why it is important to repeat experiments in scientific investigations.

Q6 (3 marks)

Use the provided data to calculate the mean and standard deviation. Discuss the reliability of the results.

Data:

Length of seedlings (mm): 20, 22, 25, 26, 23, 24, 21, 23, 25

Q7 (4 marks)

Describe the method used to separate a mixture of sand, salt, and iron filings. Explain the role of a magnet in this process.

Q8 (2 marks)

Define the term "accuracy" in the context of scientific measurements.

Q9 (3 marks)

Investigate the effect of temperature on the rate of diffusion of a dye across a membrane. Explain how you would ensure the validity of your results.

Q10 (4 marks)

Design an experiment to investigate the effect of fertilizer concentration on the growth of tomato plants. Discuss how you would control for other variables that could affect plant growth.

Mark Schemes: