Biological molecules — Paper 1 · IGCSE Science - Combined 0653

2 A test-tube contains a solution of the enzyme catalase. Which colour is obtained when this solution is tested with biuret solution? A blue B blue-black C orange D violet-mauve

1 marks

Answer: D

This question in 0653/11 May/June 2006

3 In what form is carbohydrate stored in a leaf? A fat B protein C starch D Vitamin C

1 marks

Answer: C

This question in 0653/11 May/June 2006

2 Which type of chemical is the enzyme catalase? A fat B protein C starch D sugar

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2006

4 Four foods are each tested separately with Benedict’s, biuret and iodine solutions. Which food contains starch and reducing sugar? food | Benedict’s test biuret test iodine test A v v x B v x v Cc x x v D x v x key v¥ = positive result X = negative result

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2006

3 The flow diagram shows the stages in testing a green leaf for starch. 1, 2, 3 and 4 are all liquids. 4 iodine solution white tile hot water 1 2 3 boiling water boiling alcohol warm water What are the colours of liquids 1, 2, 3 and 4 at the end of each stage for a leaf that contains starch? 1 2 3 4 A colourless green colourless blue / black B colourless colourless green brown C green colourless colourless blue / black D green green colourless brown

1 marks

Answer: A

This question in 0653/11 May/June 2007

1 Which part of a plant cell is formed from cellulose? A cell surface membrane B cell wall C chloroplasts D cytoplasm

1 marks

Answer: B

This question in 0653/11 May/June 2008

7 The flow chart shows a green leaf being tested for the presence of starch. 1 2 3 4 boil hot boil warm 0.5 min 2 min 1 min What are substances 1, 2, 3 and 4? 1 2 3 4 A alcohol water iodine water B water alcohol water iodine C water water alcohol iodine D water water alcohol water

1 marks

Answer: D

This question in 0653/11 May/June 2008

5 A series of tests on a white liquid gave the following results. test result of test Benedict’s an orange-red colour biuret a pale blue colour iodine a blue-black colour What did the white liquid contain? A protein and starch only B protein and reducing sugar only C protein, reducing sugar and starch D reducing sugar and starch only

1 marks

Answer: D

This question in 0653/11 Oct/Nov 2008

6 The results of tests carried out on four food samples are shown. key ¥ = positive test X = negative test sample Benedict's iodine biuret test test test 1 v v x 2 v x v 3 x v x 4 x x v Which two samples contain protein? B 1and3 C 2and4 A 1 and 2 D 3and4

1 marks

Answer: C

This question in 0653/11 May/June 2009

3 Which part of a plant cell contains starch grains? A cell wall B chloroplasts C nucleus D vacuole

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2010

3 A test-tube contains a solution of an enzyme. Which colour is obtained when the biuret test is carried out on this solution? A blue B blue-black C orange D purple

1 marks

Answer: D

This question in 0653/12 May/June 2013

12 Which chemical is a building block for making proteins? A amino acid B fatty acid C glucose D glycerol

1 marks

Answer: A

This question in 0653/12 May/June 2013

4 A test-tube contains a solution of an enzyme. Which colour is obtained when the biuret test is carried out on this solution? A blue B blue-black C orange D purple

1 marks

Answer: D

This question in 0653/13 May/June 2013

3 Enzymes are made from A fat. B hormones. C proteins. D starch.

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2013

4 The diagram shows a leaf from a plant kept in the dark for 48 hours. green area white area Which colours will be obtained if the leaf is then tested for starch with iodine solution? green area white area A blue-black blue-black B blue-black brown C brown blue-black D brown brown

1 marks

Answer: D

This question in 0653/11 May/June 2014

3 What are enzymes made of? A carbohydrate B fat C fibre D protein

1 marks

Answer: D

This question in 0653/12 May/June 2014

10 When a food is heated with Benedict’s solution, an orange colour appears. Which nutrient must be present in the food? A fat B protein C reducing sugar D starch

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2014

9 When a food is heated with Benedict’s solution, an orange colour appears. Which nutrient must be present in the food? A fat B protein C reducing sugar D starch

1 marks

Answer: C

This question in 0653/12 Oct/Nov 2014

4 Asample of food is tested with Benedict’s solution, biuret solution and iodine solution. The results are shown in the table. test final colour after test Benedict's solution blue biuret solution purple /lilac iodine solution blue/ black Which substances are present in the food sample tested? protein reducing sugar starch v v v 0 Oo WwW > v v x v x v x v v

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2015

5 Which chemical is produced from digestion of a fat? A amino acid B glycerol C glycogen D sugar

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2015

4 What is the main use in the human body of carbohydrate? A insulating against cold B making growth possible C providing energy D rebuilding damaged tissues

1 marks

Answer: C

This question in 0653/12 Oct/Nov 2015

4 To which class of compound do enzymes belong? A carbohydrates B fats C proteins D vitamins

1 marks

Answer: C

This question in 0653/12 May/June 2016

5 The table shows the results of tests carried out on a food. name of test colour obtained iodine Benedict’s biuret brown orange blue Which nutrients does the food contain? reducing sugar starch 0 OD > x « & x { x protein <x

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2016

4 A student wants to find out if a solution contains an enzyme. Which chemical should the student use? A Benedict’s solution B biuret solution C ethanol D iodine solution

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2016

6 A student is given a clear liquid. She tests the liquid with Benedict’s solution and iodine solution. The results are shown in the table. test Benedict’s solution iodine solution result orange-red colour orange-brown colour Which nutrients are present in the liquid? reducing sugar starch 0 OD > ~ OK ~*~ KOK OX

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2016

4 Which statements about enzymes are correct? 1 act as catalysts 2 can be denatured by heat 3 composed of complex carbohydrates 4 produced by cells A 1, 2 and 4 B 1 and 4 only C 2, 3 and 4 D 3 and 4 only

1 marks

Answer: A

This question in 0653/13 Oct/Nov 2016

4 The table shows the results when four foods are tested with Benedict’s solution and biuret reagent. Which food contains protein but not reducing sugar? colour obtained with colour obtained with Benedict’s solution biuret reagent A blue green B blue violet C red green D red violet

1 marks

Answer: B

This question in 0653/11 May/June 2017

4 An unknown liquid is divided into three test-tubes and tested as shown in the table. test-tube test solution added final colour in number to mixture test-tube 1 Benedict’s solution blue 2 biuret violet 3 iodine solution yellow Which conclusion about the unknown liquid is correct? A It contains reducing sugar and starch. B It contains protein and a reducing sugar. C It only contains protein. D It only contains starch.

1 marks

Answer: C

This question in 0653/12 May/June 2017

3 Which statement about enzymes is correct? A They are killed by high temperatures. B They are made from amino acids. C They are unaffected by pH. D They are used up in biological reactions.

1 marks

Answer: B

This question in 0653/13 May/June 2017

4 An unknown liquid is divided into three test-tubes and tested as shown in the table. test-tube test solution added final colour in number to mixture test-tube 1 Benedict’s solution blue 2 biuret violet 3 iodine solution yellow Which conclusion about the unknown liquid is correct? A It contains reducing sugar and starch. B It contains protein and a reducing sugar. C It only contains protein. D It only contains starch.

1 marks

Answer: C

This question in 0653/13 May/June 2017

3 What are enzymes made from? A fat B hormones C protein D starch

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2017

4 Which chemical is used to test for a food substance that contains the elements carbon, hydrogen, nitrogen and oxygen? A Benedict’s solution B biuret solution C ethanol D iodine solution

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2017

3 What are enzymes made from? A fat B hormones C protein D starch

1 marks

Answer: C

This question in 0653/12 Oct/Nov 2017

3 What are enzymes made from? A fat B hormones C protein D starch

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2017

4 Tests were performed on four samples of food. The results are shown in the table. Which food contains protein only? results of food tests Benedict’s test biuret test iodine test A blue blue blue/black B blue purple brown C red blue blue/black D red purple brown

1 marks

Answer: B

This question in 0653/12 Feb/March 2018

3 Food chewed in the mouth is mixed with enzymes which begin the process of chemical digestion. What type of molecule is an enzyme? A carbohydrate B fat C protein D vitamin

1 marks

Answer: C

This question in 0653/11 May/June 2018

3 When biuret solution is added to a food sample it turns purple. What must the food sample contain? A fat B glycerol C protein D vitamin

1 marks

Answer: C

This question in 0653/12 May/June 2018

3 When biuret solution is added to a food sample it turns purple. What must the food sample contain? A fat B glycerol C protein D vitamin

1 marks

Answer: C

This question in 0653/13 May/June 2018

4 A food substance was tested with various reagents. The results of the tests are shown. Benedict’s reagent biuret ethanol iodine solution solution turned stayed went went result orange pale blue milky blue / black Which element did the food substance not contain? A carbon B hydrogen C nitrogen D oxygen

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2018

3 Enzymes are used in digestion to break down larger molecules into smaller molecules. Which row matches the large molecules with the small molecules they are broken down into? large molecules small molecules A fat glycerol and fatty acids B glycogen glycerol and amino acids C protein simple sugars D starch amino acids

1 marks

Answer: A

This question in 0653/12 Oct/Nov 2018

4 The table shows the results of three food tests carried out on the same food sample. name of solution colour change observed Benedict’s blue to orange biuret remains blue iodine brown to black Which nutrients are present in the food sample? A protein, reducing sugar and starch B protein and reducing sugar only C reducing sugar and starch only D starch only

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2018

4 Vegetarians do not eat meat. Which nutrient in meat do vegetarians need to get from other kinds of food? A fibre B protein C starch D vitamin C

1 marks

Answer: B

This question in 0653/12 Feb/March 2019

3. Which row shows the elements contained in a fat molecule? carbon hydrogen nitrogen oxygen v v v v 0 Oo WwW > v x v x v v Xx v x v v v

1 marks

Answer: C

This question in 0653/12 May/June 2019

3 Nitrates in the soil are taken up by the roots of a plant. What are the nitrates used to make? A fat B glucose C protein D starch

1 marks

Answer: C

This question in 0653/12 Oct/Nov 2019

3 Nitrates in the soil are taken up by the roots of a plant. What are the nitrates used to make? A fat B glucose C protein D starch

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2019

4 Which smaller molecule is used to make proteins? A amino acid B fatty acid C glucose D glycerol

1 marks

Answer: A

This question in 0653/12 Feb/March 2020

4 Which row shows what starch molecules and protein molecules are made from? starch proteins A glucose amino acids B glucose fatty acids C glycerol amino acids D glycerol fatty acids

1 marks

Answer: A

This question in 0653/11 May/June 2020

3 Asample of food contains only fat, protein and water. Which food tests give a positive result when the sample is tested? Benedict's biuret ethanol iodine solution solution emulsion solution Jv Jv x x v x x Jv x Jv J x x Jv J Jv

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2020

4 A student has samples of food and wants to test them for starch. What should the student use to do this? A Benedict’s solution B iodine solution C limewater D water and ethanol

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2020

2 Which row is correct? elements contained in substance substance carbon hydrogen | nitrogen oxygen A carbohydrates v v v x B carbohydrates v v x x Cc proteins Jv Jv v v D proteins x Jv Jv Jv

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2020

3 What are the smaller molecules that make up fats, protein and starch? fats protein starch A glucose glycogen fatty acids and glycerol B glucose amino acids glycogen C fatty acids and glycerol amino acids glucose D fatty acids and glycerol glycogen amino acids

1 marks

Answer: C

This question in 0653/12 Feb/March 2021

4 What are enzymes made from? A carbohydrates B fats C proteins D sugars

1 marks

Answer: C

This question in 0653/12 Feb/March 2021

3 Which row shows the elements that occur in all proteins? carbon hydrogen nitrogen oxygen A yes yes yes no B yes yes no yes C yes no yes yes D yes yes yes yes

1 marks

Answer: D

This question in 0653/11 May/June 2021

3 A student tests an unknown substance with biuret reagent. It produces a violet colour. What is the unknown substance an example of? A fat B protein C reducing sugar D starch

1 marks

Answer: B

This question in 0653/12 May/June 2021

2 The table shows the results of some food tests carried out on one sample of food. colour at start colour at end food test reagent of test of test Benedict’s solution blue blue biuret reagent blue purple iodine solution brown blue / black Which nutrients does the food sample contain? A protein and starch B protein and reducing sugar C starch only D starch and reducing sugar

1 marks

Answer: A

This question in 0653/13 May/June 2021

4 The flow diagram shows the stages in testing a green leaf for starch. 1, 2, 3 and 4 are all liquids. 4 iodine solution white tile hot water 1 2 3 boiling water boiling alcohol to warm water to kill the leaf remove the chlorophyll to wash the leaf What are the colours of liquids 2 and 4 for a leaf that contains starch? 2 4 A green blue / black B colourless brown C colourless blue / black D green brown

1 marks

Answer: A

This question in 0653/13 May/June 2021

3 Which row shows the correct reagents for food tests? reducing fats and oils proteins sugars A Benedict’s biuret ethanol B ethanol biuret Benedict’s C Benedict’s iodine ethanol D ethanol iodine Benedict’s

1 marks

Answer: B

This question in 0653/12 Feb/March 2022

3 The table shows the results of tests carried out on a food sample. test carried out final colour Benedict’s orange biuret blue ethanol emulsion milky white iodine brown What is present in the food sample? A oil and protein B oil and reducing sugar C protein and starch D reducing sugar and starch

1 marks

Answer: B

This question in 0653/11 May/June 2022

6 Which ingredient of a cake contains the most protein per gram? A egg B flour C oil D sugar

1 marks

Answer: A

This question in 0653/12 May/June 2022

4 Which large molecules are made from smaller molecules of glucose? A amino acids and fatty acids B glycogen and glycerol C glycerol and fatty acids D starch and glycogen

1 marks

Answer: D

This question in 0653/13 May/June 2022

4 A student tests samples of four different foods. Which row is the correct result for a sample containing only fat and starch? Benedict’s biuret ethanol iodine solution test emulsion solution A blue purple clear blue-black B blue blue cloudy blue-black C red purple clear brown D red blue cloudy brown

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2022

3. Food tests are carried out on a biscuit. The results of the food tests are shown. test for colour observed fat protein reducing sugar starch white emulsion blue-black Which biological molecules are present in the biscuit? fat protein sugar starch A v x x x B v x v v Cc x v v v D x v x x

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2022

3. Food tests are carried out on a biscuit. The results of the food tests are shown. test for colour observed fat white emulsion protein blue reducing sugar orange starch blue-black Which biological molecules are present in the biscuit? fat protein sugar starch A v x x x B v x v v Cc x v v v D x v x x

1 marks

Answer: B

This question in 0653/13 Oct/Nov 2022

3 The results of tests carried out on four food samples are shown. Which two samples contain protein? A 1 Jv Jv x 2 Jv x J 3 x Jv x 4 x x J key / = positive result X = negative result 1 and 2 B 1 and 3 C 2and4 D 3and4

1 marks

Answer: C

This question in 0653/12 Feb/March 2023

4 Which type of molecule is an enzyme? A carbohydrate B fat C protein D vitamin

1 marks

Answer: C

This question in 0653/12 Feb/March 2023

9 Which descriptions of food molecules before and after chemical digestion are correct? food molecules before food molecules after chemical digestion chemical digestion A large and insoluble small and soluble B large and soluble small and insoluble C small and insoluble large and soluble D small and soluble large and insoluble

1 marks

Answer: A

This question in 0653/12 Feb/March 2023

3 The table shows the results of tests carried out on a sample of food. test result Benedict’s orange iodine brown biuret purple Which nutrients are in the food? A protein, reducing sugar and starch B protein and reducing sugar only C protein and starch only D reducing sugar and starch only

1 marks

Answer: B

This question in 0653/11 May/June 2023

3 The table shows the results of tests carried out on a food. name of test colour obtained iodine Benedict’s biuret Which nutrients does the food contain? reducing sugar starch 00D D> x « & x \ x brown orange blue protein \ \ x

1 marks

Answer: B

This question in 0653/12 May/June 2023

3 A student tests a liquid with Benedict’s solution and iodine solution. The results are shown. test result Benedict’s solution orange-red colour iodine solution orange-brown colour Which nutrients are present in the liquid? reducing starch sugar A J Jv B Jv x Cc x v D x x

1 marks

Answer: B

This question in 0653/13 May/June 2023

3 What is glycogen made up from? A amino acids B fatty acids C glucose D glycerol

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2023

2 Which row shows the elements that make up proteins? carbon hydrogen nitrogen oxygen v v x v S44 v x x v

1 marks

Answer: D

This question in 0653/12 Oct/Nov 2023

2 Which row shows the elements that make up proteins? carbon hydrogen nitrogen oxygen v v x v S44 v x x v

1 marks

Answer: D

This question in 0653/13 Oct/Nov 2023

3 What are enzymes made from? A fat B protein C starch D oil

1 marks

Answer: B

This question in 0653/13 Oct/Nov 2023

3 What are the smaller molecules that make up fats, protein and starch? fats protein starch A glucose glycogen fatty acids and glycerol B glucose amino acids glycogen C fatty acids and glycerol amino acids glucose D fatty acids and glycerol glycogen amino acids

1 marks

Answer: C

This question in 0653/12 Feb/March 2024

3 Glycogen, protein and starch are large molecules. Which row correctly names the smaller molecules that combine to produce these large molecules? large molecules glycogen protein starch A glucose amino acids glucose B glucose amino acids glycerol C glycerol fatty acids glycerol D glycerol fatty acids glucose

1 marks

Answer: A

This question in 0653/11 May/June 2024

4 A student tests a biological molecule using biuret solution. The solution turns purple. Which elements make up the biological molecule? A carbon, hydrogen, oxygen and nitrogen B carbon and hydrogen only C carbon, hydrogen and oxygen only D carbon, hydrogen and nitrogen only

1 marks

Answer: A

This question in 0653/13 May/June 2024

2 Which row is correct? starch proteins fats A made from amino acids made from glucose made from glycerol B made from amino acids made from glucose made from fatty acids and glycerol C made from glucose made from amino acids made from fatty acids and glycerol D made from glucose made from glycerol made from amino acids

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2024

3 When a food sample is heated with Benedict’s solution, an orange colour appears. Which nutrient must be present in the food? A fat B protein C reducing sugar D starch

1 marks

Answer: C

This question in 0653/12 Oct/Nov 2024

3 When a food sample is heated with Benedict’s solution, an orange colour appears. Which nutrient must be present in the food? A fat B protein C reducing sugar D starch

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2024

3 Which statement about large molecules is correct? A Fats are made from fatty acids and glucose. B Glycogen forms part of a starch molecule. C Proteins are made from amino acids. D Starch contains glycerol.

1 marks

Answer: C

This question in 0653/12 Feb/March 2025

4 Which small molecules join together to form large oil molecules? A amino acids and glucose B amino acids and glycerol C fatty acids and glucose D fatty acids and glycerol

1 marks

Answer: D

This question in 0653/11 May/June 2025

5 What are the chemical elements in an enzyme? A carbon, oxygen, hydrogen and nitrogen B carbon, oxygen and hydrogen only C carbon and oxygen only D oxygen and nitrogen only

1 marks

Answer: A

This question in 0653/12 May/June 2025

3 The diagram shows a food test on some food in solution. heat in water-bath add an equal volume of Benedict’s solution 2 cm3 of brick-red food in solution precipitate Which biological molecule does the food test show that the food in solution contains? A fat B protein C reducing sugar D starch

1 marks

Answer: C

This question in 0653/13 May/June 2025

3 A sample of food turns Benedict’s solution brick-red. Which row shows the molecule the food contains and all the chemical elements in the molecule? molecule chemical elements A protein carbon, nitrogen and oxygen B glucose hydrogen, carbon and nitrogen C glucose hydrogen, carbon and oxygen D protein hydrogen, nitrogen and oxygen

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2025

4 Which biological molecule is made from amino acids? A fat B protein C starch D sugar

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2025

4 Which biological molecule is made from amino acids? A fat B protein C starch D sugar

1 marks

Answer: B

This question in 0653/13 Oct/Nov 2025