Explain how a competitive inhibitor reduces the rate of an enzyme-controlled reaction.
A scientist investigated the effect of a competitive inhibitor, substance Q, on the rate of reaction of an amylase enzyme.
The results are shown in Figure 1.
Use Figure 1 to explain why the scientist concluded that inhibitor Q is a competitive inhibitor.
A student used a light microscope at a magnification of ×400 \times 400\,×400 to observe chloroplasts within plant mesophyll cells.
The maximum length of chloroplast X, when measured with a millimetre-interval ruler on a printout of the micrograph, is exactly 24 mm.
Calculate the actual maximum length of chloroplast X in micrometres (μm\mu\text{m}μm).
Using a ruler with millimetre intervals always includes an uncertainty in the measurement. Use the uncertainty in your measurement to determine the uncertainty of your calculated maximum length. You can assume there is no uncertainty in the magnification.
Practise AQA A Level Biology Proteins with exam-style questions for A Level Biology. 22 questions covering General properties of proteins and Many proteins are enzymes, matched to the AQA A Level Biology (7402) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
