Biological molecules — Paper 2 · IGCSE Sciences - Co-ordinated (Double) 0654

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 0654/21 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 0654/22 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 0654/23 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 0654/21 Oct/Nov 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 0654/22 Oct/Nov 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 0654/23 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 0654/21 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 0654/22 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 0654/23 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 0654/21 Oct/Nov 2020

3 Which type of biological molecule contains carbon, hydrogen, oxygen and nitrogen? A fat B protein C reducing sugar D starch

1 marks

Answer: B

This question in 0654/22 Oct/Nov 2020

3 What 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 0654/23 Oct/Nov 2020

3 What are the molecules that make up fats and oils? A amino acids and glycerol B fatty acids and glycerol C glucose and amino acids D glucose and fatty acids

1 marks

Answer: B

This question in 0654/22 Feb/March 2021

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 0654/21 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 0654/22 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 0654/22 May/June 2021

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

1 marks

Answer: B

This question in 0654/21 Oct/Nov 2021

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

1 marks

Answer: B

This question in 0654/22 Oct/Nov 2021

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

1 marks

Answer: B

This question in 0654/23 Oct/Nov 2021

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

1 marks

Answer: D

This question in 0654/22 Feb/March 2022

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 0654/21 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 0654/22 May/June 2022

3 Large biological molecules are made from smaller molecules joined together. Which large molecule is correctly matched with its smaller molecule? large molecule smaller molecule A fat amino acid B glycogen glucose C starch fatty acid D protein glycerol

1 marks

Answer: B

This question in 0654/23 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 0654/21 Oct/Nov 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 0654/22 Oct/Nov 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 0654/23 Oct/Nov 2022

3 Tests are carried out on a colourless liquid. The results are shown. test resultant colour biuret purple ethanol emulsion white iodine brown Which food groups does the liquid contain? A protein and fat B protein and starch C reducing sugar and fat D starch and fat

1 marks

Answer: A

This question in 0654/22 Feb/March 2023

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 0654/21 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 0654/22 May/June 2023

3 Eggs contain fat, protein and water. Which results are obtained from doing food tests on an egg? ethanol Benedict’s test biuret test iodine test emulsion test A blue purple white emulsion yellow B orange purple white emulsion blue-black C orange blue colourless yellow D blue blue colourless blue-black

1 marks

Answer: A

This question in 0654/23 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 0654/21 Oct/Nov 2023

3 A colourless liquid gives the test results shown. test colour obtained Benedict’s blue biuret purple iodine blue / black Which nutrients are in the colourless liquid? A protein, reducing sugar and starch B protein and reducing sugar only C protein and starch only D protein only

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2023

3 Which row identifies the elements that are found in a protein molecule? carbon hydrogen nitrogen oxygen 00 WwW > x NON SN 48 \ \ x SN 48

1 marks

Answer: C

This question in 0654/22 Feb/March 2024

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 0654/21 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 0654/22 May/June 2024

3 A student tests a sample of food to identify its composition. The results are shown. test final colour of test Benedict’s test brick-red precipitate biuret test blue iodine solution blue-black Which substances are shown to be present in the food sample? A protein, reducing sugar and starch B protein and starch only C reducing sugar and starch only D reducing sugar and protein only

1 marks

Answer: C

This question in 0654/23 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 0654/21 Oct/Nov 2024

3 Which large molecule is made from many smaller glucose molecules? A amino acid B glycerol C glycogen D protein

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2024

3 Four different foods labelled A, B, C and D are tested to find out which nutrients they contain. Which food contains both starch and protein but no reducing sugar? final colour with final colour with final colour with Benedict’s solution biuret solution iodine solution A blue blue orange B blue purple blue-black C red blue orange D red purple blue-black

1 marks

Answer: B

This question in 0654/23 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 0654/21 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 0654/22 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 0654/21 Oct/Nov 2025

3 Which molecule is a component of proteins? A C2H5NO2 B C3H8O3 C C6H12O6 D C10H20O2

1 marks

Answer: A

This question in 0654/22 Oct/Nov 2025