AQA Biology A level Required Practical

Which of the following variables could be investigated to determine its effect on enzyme activity?

• pH

• Temperature

• Substrate concentration

• All of the above

What is a common limitation when measuring the rate of an enzyme-controlled reaction?

• Difficulty in maintaining constant temperature

• Inaccurate measurement of enzyme concentration

• pH fluctuations during the reaction

• All of the above

When plotting a graph of enzyme activity against temperature, which of the following is typically observed?

• A linear increase

• A bell-shaped curve

• A constant rate

• A rapid decline

If an enzyme shows maximum activity at pH 7, what conclusion can be drawn about its optimal environment?

• It functions best in acidic conditions

• It functions best in neutral conditions

• It functions best in alkaline conditions

• pH has no effect on its activity

Which stain is used to observe the stages of mitosis in root tips?

• Iodine

• Methylene blue

• Acetic orcein

• Safranin

A limitation of Required Practical 2: Preparation of stained squashes of cells from plant root tips; set up and use of an optical microscope to identify the stages of mitosis in these stained squashes is:

• Difficulty in distinguishing between different stages of mitosis

• Inability to stain the chromosomes

• Lack of availability of root tips

• Excessive time required for staining

When drawing a graph of the number of cells in each stage of mitosis, which type of graph is most appropriate?

• Line graph

• Bar chart

• Pie chart

• Scatter plot

If a high percentage of cells are observed in interphase, what does this indicate about the cell population?

• Rapid cell division

• High metabolic activity

• Low mitotic index

• High mutation rate

What is the primary purpose of creating a dilution series in the osmosis practical?

• To measure enzyme activity

• To determine the solubility of a solute

• To establish a range of known concentrations

A limitation of using potato tuber cells for determining water potential is:

• Variability in potato cell solute concentration

• Difficulty in cutting uniform potato pieces

• Inaccurate measurement of solution volumes

• All of the above