Biological molecules — IGCSE Biology (0970) questions by topic
Biological molecules questions use DCPIP to estimate vitamin C loss during cooking, match elements and small molecules to a named large molecule, identify which elements appear in proteins, and interpret a chain-of-circles diagram representing amino acids in a protein.
Choose, identify, state, explain and calculate lead 19 real questions worth 1 to 9 marks from 2023 to 2025 papers. Because these questions often hinge on matching an element list to the right molecule category, submitting each attempt for instant marking catches a mismatched row, such as proteins missing nitrogen, before it repeats across a whole set of similar questions.
May–June 2025, Paper 11
Which row correctly shows the elements and small molecules that are found in a large molecule? elements small molecules large molecule --- --- --- --- A carbon, hydrogen, oxygen,…
Answer this question and get it marked →May–June 2025, Paper 12
Small molecules are used to synthesise large food molecules. Which statement is correct? A Amino acids are the basic units of carbohydrates. B Fatty acids are the basic units of…
Answer this question and get it marked →A student used biuret reagent to test milk for the presence of protein. The milk tested positive for protein. Which colour did the sample change to? A blue B blue-black C brick…
Answer this question and get it marked →May–June 2025, Paper 21
A DNA molecule contains pairs of bases. What is a correct combination of a pair of bases? A A and G B C and A C G and T D T and A
Answer this question and get it marked →What is the test for protein? name of the test heat colour change --- --- --- --- A Benedict's yes blue to purple B biuret yes blue to red C biuret no blue to purple D Benedict's…
Answer this question and get it marked →May–June 2025, Paper 22
What is the chemical formula of glucose? A C6H6O6 B C6HO6 C C6H12O6 D C12H12O6
Answer this question and get it marked →May–June 2024, Paper 11
Large biological molecules are made of smaller molecules. Which row correctly matches the large molecule with the smaller molecules? Columns: large molecule; smaller molecules. A…
Answer this question and get it marked →A student tests a solution for protein. Which row shows the correct food test and a positive result? Columns: name of test; colour seen with a positive result. A Benedict's test;…
Answer this question and get it marked →May–June 2024, Paper 12
Iodine solution is added to a food sample that contains starch. What is the colour of the sample after the iodine solution has been added? A blue-black B purple C red D yellow
Answer this question and get it marked →May–June 2024, Paper 21
A test was performed on a food substance. A positive result was shown by a colour change to blue-black. What solution was used for the test? A biuret solution B DCPIP solution C…
Answer this question and get it marked →May–June 2024, Paper 51
Cooking fruit and vegetables in water reduces their vitamin C content. The vitamin C is transferred from the fruit and vegetables to the water by diffusion. DCPIP can be used to…
Answer this question and get it marked →May–June 2024, Paper 61
Cooking fruit and vegetables in water reduces their vitamin C content. The vitamin C is transferred from the fruit and vegetables to the water by diffusion. DCPIP can be used to…
Answer this question and get it marked →May–June 2023, Paper 11
The diagram shows part of a protein molecule with one repeating unit labelled X. What does X represent? A amino acid B fatty acid C glycerol D sugar
Answer this question and get it marked →May–June 2023, Paper 12
The diagram represents a protein molecule made of a chain of small circles. What do the small circles represent? A amino acids B fatty acids C glycerol D simple sugars
Answer this question and get it marked →May–June 2023, Paper 21
The diagram shows part of a protein molecule with one repeating unit labelled X. What does X represent? A amino acid B fatty acid C glycerol D sugar
Answer this question and get it marked →October–November 2023, Paper 12
Which row identifies the chemical elements in proteins? The table considers carbon, hydrogen, oxygen and nitrogen (key: shaded = present, blank = absent). A B C D
Answer this question and get it marked →The table shows some large biological molecules and some small biological molecules: 1 cellulose / glucose 2 oil / amino acids 3 glycogen / glucose 4 protein / ethanol Which rows…
Answer this question and get it marked →October–November 2023, Paper 22
Which row identifies the chemical elements in proteins? The table considers carbon, hydrogen, oxygen and nitrogen (key: shaded = present, blank = absent). A B C D
Answer this question and get it marked →The table shows some large biological molecules and some small biological molecules: 1 cellulose / glucose 2 oil / amino acids 3 glycogen / glucose 4 protein / ethanol Which rows…
Answer this question and get it marked →Other IGCSE Biology topics
- Human nutrition (75)
- Organisms and their environment (64)
- Coordination and response (62)
- Reproduction (53)
- Organisation of the organism (cells) (50)
- Plant nutrition (42)
- Characteristics and classification of living organisms (40)
- Variation and selection (40)
- Transport in animals (39)
- Inheritance (39)
- Movement into and out of cells (38)
- Transport in plants (38)