Enzymes — IGCSE Sciences - Co-Ordinated (0973) questions by topic
Enzymes questions identify the type of molecule enzymes are, which molecules speed up chemical digestion, what denaturation means at pH away from the optimum, and which graph shows enzyme activity rising then falling with temperature, worth from 1 to 11 marks in this IGCSE Co-ordinated Sciences set.
Identify, state, complete and draw are the top command words: draw or select a curve that peaks at an optimum before falling sharply, not a gradual decline. 15 real questions from 2023 to 2025 papers make up this page. Submit each attempt for instant marking so a denaturation definition confused with a simple activity decrease is caught immediately.
May–June 2025, Paper 11
Which type of molecules are enzymes? A carbohydrates B fats C hormones D proteins
Answer this question and get it marked →May–June 2025, Paper 12
Which statements about enzymes are correct? 1 Enzymes are biological catalysts. 2 Enzymes are made of fat. 3 Enzymes are made of protein. A 1 and 2 B 1 and 3 C 1 only D 3 only
Answer this question and get it marked →May–June 2025, Paper 21
Which type of molecule are enzymes? A carbohydrate B DNA C fat D protein
Answer this question and get it marked →May–June 2025, Paper 22
Six test-tubes contain amylase and starch solution. The temperatures of the test-tube contents are different. All other conditions are the same. The table shows the time taken for…
Answer this question and get it marked →May–June 2024, Paper 11
Which type of molecules are enzymes? A carbohydrates B fats C oils D proteins
Answer this question and get it marked →May–June 2024, Paper 21
Which statement about denaturation is correct? A Denaturation is the change in shape of the active site of the enzyme at a pH above the optimum pH. B Denaturation is the change in…
Answer this question and get it marked →May–June 2024, Paper 22
The graph shows the mass of product produced by an enzyme-controlled reaction over time at 37 C and at 60 C (substrate and enzyme concentrations constant). The 60 C curve is…
Answer this question and get it marked →May–June 2024, Paper 31
Fig. 10.1 shows the activity of some bacterial enzymes (A-E) at different temperatures (each peaking at a different optimum). Complete the sentences to describe the results in…
Answer this question and get it marked →May–June 2023, Paper 11
Which type of molecule are enzymes? A amino acids B carbohydrates C fats D proteins
Answer this question and get it marked →May–June 2023, Paper 12
Which type of molecules speed up chemical digestion? A carbohydrates B enzymes C hormones D fatty acids
Answer this question and get it marked →May–June 2023, Paper 21
Which row about enzymes is correct? [Table: rows A-D each marked true/false against statements: 'each enzyme catalyses many different reactions', 'the active site is the part of…
Answer this question and get it marked →May–June 2023, Paper 22
Which type of molecules speed up chemical digestion? A carbohydrates B enzymes C hormones D fatty acids
Answer this question and get it marked →October–November 2023, Paper 11
Which graph shows the effect of temperature on enzyme activity? [Graphs A-D: enzyme activity vs temperature; D rises to an optimum then falls sharply.] A graph A B graph B C graph…
Answer this question and get it marked →October–November 2023, Paper 21
The graph shows the effect of increasing temperature on the time taken for amylase to fully digest a sample of starch (the time falls to a minimum then rises again). [Graph: time…
Answer this question and get it marked →October–November 2023, Paper 41
A scientist measures the activity of the enzyme amylase at different temperatures. Fig. 7.1 shows a graph of enzyme activity / arbitrary units against temperature / C (rising to…
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