Biological molecules — Paper 2 · IGCSE Sciences - Co-ordinated (9-1) 0973

3 Which chemical element is found in proteins, but not in carbohydrates or fats? A carbon B hydrogen C oxygen D nitrogen

1 marks

Answer: D

This question in 0973/21 May/June 2019

3 Which chemical element is found in proteins, but not in carbohydrates or fats? A carbon B hydrogen C oxygen D nitrogen

1 marks

Answer: D

This question in 0973/22 May/June 2019

3 Which result with the biuret test shows that protein is present? A blue B green C orange D purple

1 marks

Answer: D

This question in 0973/21 Oct/Nov 2019

3 A food contains reducing sugar, but no starch. What colours will be obtained if samples of the food are tested with Benedict’s solution and with iodine solution? Benedict’s test iodine test A blue blue-black B blue brown C red-orange blue-black D red-orange brown

1 marks

Answer: D

This question in 0973/21 May/June 2020

3 A food contains reducing sugar, but no starch. What colours will be obtained if samples of the food are tested with Benedict’s solution and with iodine solution? Benedict’s test iodine test A blue blue-black B blue brown C red-orange blue-black D red-orange brown

1 marks

Answer: D

This question in 0973/22 May/June 2020

3 Nutrient molecules are made up from smaller molecules. Nutrients can be identified by food tests. Which row is true for a protein? smaller molecules test which gives a positive result A amino acids Benedict’s test B amino acids biuret test C sugars Benedict’s test D sugars biuret test

1 marks

Answer: B

This question in 0973/21 Oct/Nov 2020

3 Three food tests are carried out on a sample of food. The results are shown in the table. food test final colour Benedict’s blue biuret blue iodine blue-black From these results, which nutrient is in the food? A reducing sugar B protein C starch D vitamin C

1 marks

Answer: C

This question in 0973/21 May/June 2021

4 What is an enzyme? A a carbohydrate that speeds up the rate of a reaction B a carbohydrate that alters the activity of a target organ C a protein that alters the activity of a target organ D a protein that speeds up the rate of a reaction

1 marks

Answer: D

This question in 0973/21 May/June 2021

3. Which row matches the nutrient to the chemical elements that it contains? nutrient fat protein starch sugar carbon hydrogen oxygen nitrogen / = contains element X = does not contain element

1 marks

Answer: B

This question in 0973/22 May/June 2021

4 Which type of molecule are enzymes? A fat B carbohydrate C protein D DNA

1 marks

Answer: C

This question in 0973/22 May/June 2021

3 Which molecule contains carbon? A ammonia B fat C sulfuric acid D water

1 marks

Answer: B

This question in 0973/21 Oct/Nov 2021

3 Which small molecules are joined together to make a starch molecule? A amino acids B fatty acids C glucose D glycerol

1 marks

Answer: C

This question in 0973/21 May/June 2022

3 Which reagent is used to test for the presence of protein in a food sample? A Benedict’s solution B biuret C ethanol D iodine

1 marks

Answer: B

This question in 0973/22 May/June 2022

3 Glycerol is a component of which large molecules? A fats B glycogen C proteins D starch

1 marks

Answer: A

This question in 0973/21 Oct/Nov 2022

3 Linoleic acid is a fatty acid. Which larger molecule may contain linoleic acid? A glycogen B oil C protein D starch

1 marks

Answer: B

This question in 0973/21 May/June 2023

3 Which row shows the elements and the small molecules that are used to make the larger molecules? small larger elements molecule molecule A carbon, hydrogen and oxygen glucose fats B carbon, hydrogen, oxygen and nitrogen amino acids fats C carbon, hydrogen and oxygen glucose proteins D carbon, hydrogen, oxygen and nitrogen amino acids proteins

1 marks

Answer: D

This question in 0973/22 May/June 2023

3 Which colour does Benedict’s solution change to when heated with a reducing sugar? A blue B blue-black C orange D purple

1 marks

Answer: C

This question in 0973/21 Oct/Nov 2023

3 A sample of food is tested for reducing sugars by adding Benedict’s solution and heating. What indicates that reducing sugars are present? A a blue-black colour B a brick-red precipitate C a purple colour D a white emulsion

1 marks

Answer: B

This question in 0973/21 May/June 2024

3 Analysis of a large food molecule shows that it contains the elements carbon, hydrogen and oxygen only. Which food groups could this molecule be from? A carbohydrates and fats only B carbohydrates and proteins only C fats and proteins only D carbohydrates, fats and proteins

1 marks

Answer: A

This question in 0973/22 May/June 2024

3 Which biological molecule contains the elements carbon, hydrogen, nitrogen and oxygen? A carbohydrate B fat C oil D protein

1 marks

Answer: D

This question in 0973/21 Oct/Nov 2024

1 Which result with the biuret test shows that protein is present? A blue B green C orange D purple

1 marks

Answer: D

This question in 0973/21 May/June 2025

3 Which type of molecule are enzymes? A carbohydrate B DNA C fat D protein

1 marks

Answer: D

This question in 0973/21 May/June 2025

4 Which row shows a large molecule and the small molecule it is made from? large molecule small molecule A glycogen glucose B glycogen amino acid C oil amino acid D oil glucose

1 marks

Answer: A

This question in 0973/22 May/June 2025

4 A student tests a sample of food for the presence of different biological molecules. The results of the tests are shown. test results of test add iodine solution orange-brown colour heat with Benedict’s solution red precipitate formed add biuret reagent lilac colour ethanol emulsion test clear solution Which biological molecules are present in the food? A fat and starch B reducing sugars and protein C reducing sugars and starch D starch and protein

1 marks

Answer: B

This question in 0973/21 Oct/Nov 2025