Biological molecules — IGCSE Biology (0610) questions by topic

Biological molecules questions identify the smaller molecules that build glycogen, state the element found in all proteins but absent from carbohydrates and fats, match elements and small molecules to a named large molecule, and identify which row correctly shows carbon, hydrogen, oxygen and nitrogen in proteins.

Identify, state, complete and draw carry 1 to 18 marks across 36 real questions from 2023 to 2025 papers, this topic's only syllabus point without explain among its top command words. Because these questions reward exact recall of which elements or building blocks belong to which molecule, submitting each answer for instant marking flags a swapped element or monomer before it repeats across a related set.

May–June 2025, Paper 11

Question 9 · 1 mark

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,…

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Question 10 · 1 mark

Which substance is the DCPIP test used for? A fat B protein C starch D vitamin C

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May–June 2025, Paper 12

Question 7 · 1 mark

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…

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Question 8 · 1 mark

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…

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May–June 2025, Paper 13

Question 8 · 1 mark

Which chemical tests should a student use to test lemon juice for reducing sugars and vitamin C? reducing sugars vitamin C --- --- --- A Benedict's solution test DCPIP solution…

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Question 11 · 1 mark

Which carbohydrate is used to build plant cell walls? A cellulose B glycogen C starch D sucrose

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May–June 2025, Paper 21

Question 6 · 1 mark

What is the test for protein? The table gives, for each row, the name of the test, whether heat is required, and the colour change. name of the test heat colour change --- --- ---…

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May–June 2024, Paper 33

Question 1 · 8 marks

Water is an important biological molecule. The box on the left contains the word 'Water'. The boxes on the right contain some sentence endings. Draw a line from the box on the…

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Question 2 · 18 marks

Biological molecules are made of chemical elements. Complete Table 2.1 by placing ticks (✓) in the boxes to show which chemical elements each biological molecule is made from.…

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October–November 2024, Paper 11

Question 9 · 1 mark

Which substances are made by linking together glucose molecules only? A cellulose, glycogen and starch B fats, cellulose and proteins C proteins, oils and glycogen D starch, fats…

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Question 10 · 1 mark

Four solutions were tested to see if they contained protein, starch or glucose. The colours of the solutions after the tests are recorded in the table. Which solution contained…

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October–November 2024, Paper 12

Question 10 · 1 mark

A sample of food was tested with biuret reagent. Which colour would be seen if the food sample contained protein? A blue-black B brick red C yellow-brown D purple

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Question 11 · 1 mark

Which elements are found in fats? A carbon, hydrogen and iron B carbon, hydrogen and oxygen C carbon, hydrogen and nitrogen D carbon, oxygen and nitrogen

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Question 14 · 1 mark

Which carbohydrate is used to make cell walls? A cellulose B glycogen C starch D sucrose

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October–November 2024, Paper 13

Question 10 · 1 mark

A sample of food is tested with different chemical substances. The table shows the results: iodine solution - yellow-brown; biuret - purple; DCPIP - colourless. Which nutrients…

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October–November 2024, Paper 21

Question 8 · 1 mark

Which statement about biological molecules is correct? A DNA molecules contain pairs of bases: A pairs with G and C pairs with T. B Fatty acids and glycerol molecules can be…

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October–November 2024, Paper 23

Question 6 · 1 mark

Which food-testing reagent shows a positive result when it turns from blue to purple? A Benedict's solution B biuret C ethanol D iodine solution

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Question 9 · 1 mark

Which molecules contain nitrogen? A amino acids B fats C glucose D starch

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May–June 2023, Paper 11

Question 9 · 1 mark

The diagram shows part of a protein molecule, with one of the repeating sub-units labelled X. What does X represent? A amino acid B fatty acid C glycerol D sugar

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May–June 2023, Paper 12

Question 7 · 1 mark

What is a role of water in digestion? A It is an enzyme. B It is a solvent. C It is soluble. D It is a mineral.

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Question 9 · 1 mark

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

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Question 13 · 1 mark

Which row shows the uses of some carbohydrates in plants? Columns: glucose; starch; sucrose. A cell walls; transport; energy storage B energy storage; cell walls; respiration C…

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May–June 2023, Paper 13

Question 9 · 1 mark

Four different foods were tested to find out what they contained. The results are shown in the table (columns: Benedict's solution test, iodine solution test, biuret test). Which…

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May–June 2023, Paper 21

Question 7 · 1 mark

The diagram shows part of a protein molecule with one repeating sub-unit labelled X. What does X represent? A amino acid B fatty acid C glycerol D sugar

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May–June 2023, Paper 23

Question 7 · 1 mark

The table shows the results of food tests carried out on a fruit. Columns: Benedict's solution = positive; biuret = positive; ethanol emulsion = negative; iodine solution =…

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May–June 2023, Paper 43

Question 7 · 7 marks

State the name of a chemical element that is found in all proteins but not in carbohydrates or fats.

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October–November 2023, Paper 11

Question 8 · 1 mark

What is the colour change shown by Benedict's solution when heated with a reducing sugar? A blue to purple B blue to red C brown to blue-black D red to yellow

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October–November 2023, Paper 12

Question 8 · 1 mark

Which row identifies the chemical elements in proteins? Columns: carbon; hydrogen; oxygen; nitrogen (key: ✓ = present, blank = absent). Which row A–D is correct? A B C D

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Question 9 · 1 mark

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…

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October–November 2023, Paper 13

Question 8 · 1 mark

Which row shows the chemical elements contained in fats? Columns: carbon; hydrogen; nitrogen; oxygen (key: ✓ = present, blank = absent). Which row A–D is correct? A B C D

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Question 9 · 1 mark

Glycogen is a large molecule made from smaller molecules. Which smaller molecules is glycogen made from? A amino acids B fatty acids C glucose D glycerol

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October–November 2023, Paper 21

Question 8 · 1 mark

What is the colour change shown by Benedict's solution when heated with a reducing sugar? A blue to purple B blue to red C brown to blue-black D red to yellow

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October–November 2023, Paper 22

Question 8 · 1 mark

Which row identifies the chemical elements in proteins? Columns: carbon; hydrogen; oxygen; nitrogen (key: ✓ = present, blank = absent). Which row A–D is correct? A B C D

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Question 9 · 1 mark

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…

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October–November 2023, Paper 23

Question 8 · 1 mark

Which row shows the chemical elements contained in fats? Columns: carbon; hydrogen; nitrogen; oxygen (key: ✓ = present, blank = absent). Which row A–D is correct? A B C D

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Question 9 · 1 mark

Glycogen is a large molecule made from smaller molecules. Which smaller molecules is glycogen made from? A amino acids B fatty acids C glucose D glycerol

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