Biological molecules — Paper 1 · IGCSE Biology (9-1) 0970

9 The table shows the results of food tests carried out on a fruit. test Benedict’s biuret ethanol iodine result positive positive negative negative What did the fruit contain? A fat and reducing sugar B fat and starch C protein and reducing sugar D protein and starch

1 marks

Answer: C

This question in 0970/11 May/June 2018

9 The data show the concentrations of sugar and starch in an onion. total sugar including starch reducing sugar / g per 100g / g per 100g 3.7 0.0 The onion is tested with Benedict’s solution and iodine solution. Which set of results is correct? Benedict’s iodine solution solution A blue blue-black B blue brown C brick red blue-black D brick red brown

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2018

8 Four solutions were tested to see whether they contained protein, starch or glucose. The colours of the solutions after the tests are recorded in the table. Which solution contained protein and glucose but not starch? biuret test iodine test Benedict’s test A blue brown orange B blue blue-black blue C purple brown orange D purple blue-black blue

1 marks

Answer: C

This question in 0970/11 May/June 2019

9 Small molecules are used as the basic units in the synthesis of large food molecules. Which statement is correct? A Amino acids are basic units of carbohydrates. B Fatty acids are basic units of glycogen. C Glycerol is a basic unit of oils. D Simple sugar is a basic unit of protein.

1 marks

Answer: C

This question in 0970/11 May/June 2019

8 Which identifies the chemical elements found in proteins? carbon hydrogen oxygen nitrogen v v v v key J/ = present 0 0O WwW > J WA J x Jv x Jv x X = absent x Jv x WA

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2019

9 A student carries out a test to see whether the solution in a test-tube contains protein. Which row shows the correct food test and a positive result? colour seen with a name of test positive result A Benedict’s test blue-black B Benedict’s test purple C biuret test blue-black D biuret test purple

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2019

12 The pie charts show the composition of 100 g of four different foods. Which food provides the most energy? A B C D key carbohydrate fats and oils protein water

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2019

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

1 marks

Answer: B

This question in 0970/11 May/June 2020

9 What is the definition of an enzyme? A a carbohydrate that acts as a catalyst B a DNA molecule that acts as a catalyst C a fat that acts as a catalyst D a protein that acts as a catalyst

1 marks

Answer: D

This question in 0970/11 May/June 2020

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

1 marks

Answer: B

This question in 0970/12 May/June 2020

9 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 and oils

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2020

11 What kind of molecule is an enzyme? A fat B glucose C protein D starch

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2020

13 The graph shows how the percentage of protein found in potatoes was affected by the concentration of nitrate fertiliser added to the crop when it was growing. percentage of protein in potatoes concentration of nitrate fertiliser added These results suggest that greater concentrations of nitrate fertiliser allow the potatoes to make more A amino acids. B cellulose. C lipid. D starch.

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2020

9 Which element is found in proteins but not carbohydrates? A carbon B hydrogen C nitrogen D oxygen

1 marks

Answer: C

This question in 0970/11 May/June 2021

15 What are the products when proteins are broken down? A amino acids B fatty acids C glycerol D simple sugars

1 marks

Answer: A

This question in 0970/11 May/June 2021

14 What is the dietary importance of carbohydrates? A to promote healthy bones and teeth B to make fats C to provide energy for the body D to make proteins

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2021

9 What are the smaller basic units of starch and glycogen molecules? starch glycogen A amino acids fatty acids and glycerol B amino acids glucose C glucose fatty acids and glycerol D glucose glucose

1 marks

Answer: D

This question in 0970/11 May/June 2022

10 Some terms used to describe enzyme-controlled reactions are listed. 1 catalyst 2 product 3 protein 4 substrate Which terms describe an enzyme? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

1 marks

Answer: A

This question in 0970/11 May/June 2022

11 The diagram shows two food tests being carried out on solution X. test 1 test 2 biuret Benedict’s solution solution red colour heat solution X purple solution X colour Which nutrients are present in solution X? A protein and starch B protein and sugar C starch and fat D starch and sugar

1 marks

Answer: B

This question in 0970/11 May/June 2022

9 What are the smaller basic units of starch and glycogen molecules? starch glycogen A amino acids fatty acids and glycerol B amino acids glucose C glucose fatty acids and glycerol D glucose glucose

1 marks

Answer: D

This question in 0970/12 May/June 2022

10 Which type of molecule are enzymes made of? A carbohydrates B fats C proteins D vitamins

1 marks

Answer: C

This question in 0970/12 May/June 2022

11 The diagram shows two food tests being carried out on solution X. test 1 test 2 biuret Benedict’s solution solution red colour heat solution X purple solution X colour Which nutrients are present in solution X? A protein and starch B protein and sugar C starch and fat D starch and sugar

1 marks

Answer: B

This question in 0970/12 May/June 2022

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

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2022

9 The diagram shows part of a protein molecule. X What does X represent? A amino acid B fatty acid C glycerol D sugar

1 marks

Answer: A

This question in 0970/11 May/June 2023

7 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.

1 marks

Answer: B

This question in 0970/12 May/June 2023

9 The diagram represents a protein molecule. What do the small circles represent? A amino acids B fatty acids C glycerol D simple sugars

1 marks

Answer: A

This question in 0970/12 May/June 2023

8 Which row identifies the chemical elements in proteins? carbon hydrogen oxygen nitrogen A v J J J key B Jv x Jv x / = present Cc x v v v X = absent D J J x x

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2023

9 The table shows some large biological molecules and some small biological molecules. large biological small biological molecules molecules 1 cellulose glucose 2 oil amino acids 3 glycogen glucose 4 protein ethanol Which rows correctly pair large molecules with the smaller molecules used to make them? A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2023

9 Large biological molecules are made of smaller molecules. Which row correctly matches the large molecule with the smaller molecules? large molecule smaller molecules A cellulose fatty acids B fat amino acids C protein amino acids D starch fatty acids

1 marks

Answer: C

This question in 0970/11 May/June 2024

10 A student tests a solution for protein. Which row shows the correct food test and a positive result? colour seen with a name of test positive result A Benedict’s test blue-black B Benedict’s test purple C biuret test blue-black D biuret test purple

1 marks

Answer: D

This question in 0970/11 May/June 2024

10 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

1 marks

Answer: A

This question in 0970/12 May/June 2024

12 Which of these statements about enzymes are correct? 1 enzymes are proteins 2 enzymes are used up during chemical reactions 3 enzymes speed up metabolic reactions A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 0970/12 May/June 2024

10 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

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2024

11 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

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2024

12 Which statements about enzymes are correct? 1 Enzymes are biological catalysts. 2 Enzymes are carbohydrates. 3 Enzymes have an active site. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2024

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

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2024

19 What are the products of protein digestion in the stomach? A amino acids B fatty acids C glycerol D proteases

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2024

36 What do genes code for? A fats B proteins C starch D sugars

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2024

9 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, nitrogen glucose fat B carbon, hydrogen, oxygen, nitrogen glycerol fat C carbon, hydrogen, oxygen glucose starch D carbon, hydrogen, oxygen glycerol starch

1 marks

Answer: C

This question in 0970/11 May/June 2025

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

1 marks

Answer: D

This question in 0970/11 May/June 2025

7 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 glycogen. C Glycerol is a basic unit of oils. D Simple sugar is the basic unit of protein.

1 marks

Answer: C

This question in 0970/12 May/June 2025

8 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 red D purple

1 marks

Answer: D

This question in 0970/12 May/June 2025

7 Enzymes are large molecules. Which small molecules are they made from? A amino acids B carbon dioxide and water C fatty acids D sugars

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2025