Digestion — Paper 3 · IGCSE Sciences - Co-ordinated (Double) 0654

1 (a) Fig. 1.1 is a drawing of the alimentary canal and associated organs. A I H B C G D E F Fig. 1.1 (i) Name the parts labelled B and G. B … G … [2] (ii) Using Fig. 1.1, identify the letter where food is absorbed, … egestion occurs. … [2] (b) Define the term ingestion. … … … [2] (c) Draw lines between the boxes to match the digestive enzyme with its substrate and product. digestive enzyme substrate products fatty acids and protease fats glycerol lipase proteins glucose amylase starch amino acids [3]

9 marks

Mark scheme: 1(a)(i) B – stomach ; G – large intestine ; 2 1(a)(ii) D ; F ; 2 1(b) taking substances into the body ; through the mouth ; 2 1(c) protease fats fatty acids and glycerol lipase proteins glucose amylase starch amino acids ;;; 3

This question in 0654/32 May/June 2017

1 Fig. 1.1 shows the different types of human teeth in the lower jaw. X Fig. 1.1 (a) Identify the type of tooth labelled X in Fig. 1.1. … [1] (b) Describe the function of each of the following types of teeth. canine teeth … … molar teeth … … [2] (c) Explain how the action of teeth aids digestion. … … … [2] (d) Consuming too many sugary foods increases the risk of tooth decay. Describe how eating sugary foods contributes to tooth decay. … … … … [3] (e) Avoiding sugary foods is one way to decrease the risk of tooth decay. Describe one other way to reduce tooth decay. … … [1]

9 marks

Mark scheme: 1(a) incisor(s) ; 1 1(b) canine cut / tear / rip food (into smaller pieces) ; molar grind / crush food (into smaller pieces) ; 2 1(c) break food into smaller pieces ; increasing the surface area ; for enzymes to act ; max 2 1(d) bacteria feed on sugar ; ref to respiration ; producing acid ; acid causes the teeth to decay / corrode / wear away ; max 3 1(e) (regular) brushing / antibacterial mouth wash / flossing / regular visits to dentist ; 1

This question in 0654/31 Oct/Nov 2018

13 (a) In the human body digestion is required to break down large, insoluble food molecules into small, water‑soluble molecules that can be absorbed. (i) Complete Table 13.1 to describe the two types of digestion process that take place in the human body. Table 13.1 digestion process example of this process in the human body … enzymes in the stomach breaking food down mechanical digestion … [2] (ii) Describe the movement of the digested food molecules during absorption. … … [2] (b) (i) The boxes on the left show some nutrients. The boxes on the right contain the smaller units from which they are made. Draw a line from each nutrient to their correct smaller units. nutrient smaller units fats and oils amino acids proteins glucose starch glycerol and fatty acids [2] (ii) Draw a circle around all the elements that are present in fats. calcium carbon hydrogen magnesium oxygen sulfur [1] (c) Define the term balanced diet. … … … … [2]

9 marks

Mark scheme: 13(a)(i) digestion process example of this process in the human body chemical digestion enzymes in the stomach breaking food down mechanical digestion food chewed / ground by teeth owtte 2 13(a)(ii) (across wall of) small intestine; into the blood; 2 13(b)(i) nutrient smaller units fats and oils amino acids proteins glucose starch glycerol and fatty acids 1 or 2 correct; 3 correct; 2 13(b)(ii) carbon, hydrogen and oxygen circled; 1 13(c) (diet contains) all required nutrients; in sufficient / correct proportions; 2

This question in 0654/32 Oct/Nov 2018

4 (a) Table 4.1 shows the types and number of teeth in an adult human. Table 4.1 type of tooth number of tooth type in adults canine 4 incisor 8 molar 12 pre-molar 8 (i) Calculate the total number of teeth in this adult human. … [1] (ii) Use your answer in (a)(i) to calculate the percentage of human teeth which are incisors. Show your working. … % [1] (iii) Suggest why herbivores such as sheep have a larger percentage of molars than humans. Explain your answer. … … … [2] (b) There are two types of digestion. State the type of digestion that involves teeth. … [1] (c) Describe two ways to take proper care of teeth. 1 … … 2 … … [2] [Total: 7]

7 marks

Mark scheme: 4(a)(i) 32 ; 1 4(a)(ii) (8 / 32) × 100 = 25 (%) ; 1 4(a)(iii) sheep / herbivores only eat plant material (grass) ; (molars) grind / chew food ; 2 4(b) mechanical ; 1 4(c) consume less sugar ; brush teeth ; 2

This question in 0654/32 May/June 2019

4 (a) Table 4.1 shows the types and number of teeth in an adult human. Table 4.1 type of tooth number of tooth type in adults canine 4 incisor 8 molar 12 pre-molar 8 (i) Calculate the total number of teeth in this adult human. … [1] (ii) Use your answer in (a)(i) to calculate the percentage of human teeth which are incisors. Show your working. … % [1] (iii) Suggest why herbivores such as sheep have a larger percentage of molars than humans. Explain your answer. … … … [2] (b) There are two types of digestion. State the type of digestion that involves teeth. … [1] (c) Describe two ways to take proper care of teeth. 1 … … 2 … … [2] [Total: 7]

7 marks

Mark scheme: 4(a)(i) 32 ; 1 4(a)(ii) (8 / 32) × 100 = 25 (%) ; 1 4(a)(iii) sheep / herbivores only eat plant material (grass) ; (molars) grind / chew food ; 2 4(b) mechanical ; 1 4(c) consume less sugar ; brush teeth ; 2

This question in 0654/33 May/June 2019

1 (a) Fig. 1.1 is a diagram of the alimentary canal and associated organs. B A C D J E H F G Fig. 1.1 (i) State the letters in Fig. 1.1 that identify where: • egestion occurs … • ingestion occurs … • saliva is produced … • water is absorbed. … [4] (ii) Name the organ labelled J in Fig. 1.1. (iii) Name the organ labelled E in Fig. 1.1. (b) A student has written an incorrect definition for digestion in a human. The definition the student has written is shown in Fig. 1.2. Digestion is the breakdown of large, insoluble food molecules into small, oil‑soluble molecules using mechanical and industrial processes. Fig. 1.2 Circle the two incorrect terms in the definition shown in Fig. 1.2. [2] (c) Table 1.1 shows some food molecules and the smaller molecules they are made from. Complete Table 1.1. Table 1.1 food molecules smaller molecules fatty acids and glycerol amino acids starch [3] [Total: 11]

11 marks

Mark scheme: 1(a)(i) G ; A ; B ; F / H ; 4 1(a)(ii) liver ; 1 1(a)(iii) pancreas ; 1 1(b) oil (-soluble) circled ; industrial circled ; 2 1(c) food molecule smaller molecules fats / oils fatty acids and glycerol protein ; amino acids starch glucose ; 3

This question in 0654/31 Oct/Nov 2020

4 (a) In Fig. 4.1, the boxes on the left show some of the components of a balanced diet for an adult. The boxes on the right show some principal sources of these components. Draw four lines to link each component with its principal source. component principal source carbohydrate fish fat grapefruit protein noodles vitamin C olive oil [3] Fig. 4.1 (b) A person has to choose between two different menus, A and B. Fig. 4.2 shows each menu. Menu A Menu B meat burger and chicken, rice and potato chips mixed salad chocolate cake fruit and yoghurt Fig. 4.2 (i) A doctor advises a patient to eat menu B rather than menu A. Suggest two reasons why. 1 … … 2 … … [2] (ii) Both meals contain water. Table 4.1 lists some statements. Place a tick (3) to show the statement that describes why water is needed by the body. Table 4.1 as a reactant for respiration as a solvent to carry genetic information to carry oxygen in the blood to provide insulation for the body [1] (c) The food we ingest is absorbed and assimilated inside the body. (i) State where ingestion occurs. … [1] (ii) Describe one similarity and one difference between absorption and assimilation. similarity … … difference … … [2] (d) Nutrition is one of the characteristics of living things. Name two other characteristics. 1 … 2 … [2] [Total: 11]

11 marks

Mark scheme: 4(a) carbohydrate fish fats grapefruit protein noodles vitamin C olive oil ;;; 3 4(b)(i) any two from it has a greater variety of nutrients / food types ; also contains (more) fruit / vegetables ; contains less fats ; contains less sugar ; it contains more vitamins / minerals ; max 2 2 4(b)(ii) as a solvent ticked ; 1 4(c)(i) mouth ; 1 4(c)(ii) similarity – both involve movement of (digested) food; difference – absorption is into the blood / assimilation is into the cells ; 2 4(d) any two from movement ; respiration ; sensitivity ; growth ; excretion ; reproduction ; max 2 2

This question in 0654/32 Oct/Nov 2020

1 (a) Fig. 1.1 is a diagram of the alimentary canal and associated organs. B A C D J E H F G Fig. 1.1 (i) State the letters in Fig. 1.1 that identify where: • egestion occurs … • ingestion occurs … • saliva is produced … • water is absorbed. … [4] (ii) Name the organ labelled J in Fig. 1.1. … [1] (iii) Name the organ labelled E in Fig. 1.1. … [1] (b) A student has written an incorrect definition for digestion in a human. The definition the student has written is shown in Fig. 1.2. Digestion is the breakdown of large, insoluble food molecules into small, oil‑soluble molecules using mechanical and industrial processes. Fig. 1.2 Circle the two incorrect terms in the definition shown in Fig. 1.2. [2] (c) Table 1.1 shows some food molecules and the smaller molecules they are made from. Complete Table 1.1. Table 1.1 food molecules smaller molecules … fatty acids and glycerol amino acids … starch … [3] [Total: 11]

11 marks

Mark scheme: 1(a)(i) G ; A ; B ; F / H ; 4 1(a)(ii) liver ; 1 1(a)(iii) pancreas ; 1 1(b) oil (-soluble) circled ; industrial circled ; 2 1(c) food molecule smaller molecules fats / oils fatty acids and glycerol protein ; amino acids starch glucose ; 3

This question in 0654/33 Oct/Nov 2020

1 (a) It is recommended that people eat a balanced diet. Place a tick (3) next to the sentence that best describes a balanced diet. A balanced diet contains all the required nutrients in the correct amounts. A balanced diet contains the correct amounts of carbohydrates. A balanced diet contains lots of fruit and vegetables. A balanced diet contains no fats or salt. [1] (b) The boxes on the left show some nutrients. The boxes on the right show why the nutrients are needed by the body. Draw lines to link each nutrient with why it is needed by the body. nutrient why it is needed carbohydrate for bones and teeth fats insulation protein main source of energy vitamin D used for growth and repair [3] (c) List the three chemical elements that make up carbohydrates. … [1] (d) Benedict’s solution can be used to test for the presence of one type of carbohydrate. Name the carbohydrate that Benedict’s solution is used to test for. … [1] (e) Name the component of the diet that prevents constipation. … [1] (f) Eating less sugar can help prevent tooth decay. Describe one other way of taking care of teeth. … … [1] (g) Circle the two processes that occur in the mouth. ingestion digestion egestion fertilisation photosynthesis pollination transpiration [2] [Total: 10]

10 marks

Mark scheme: 1(a) A diet containing all the required nutrients in the correct amounts ticked ; 1 1(b) carbohydrate for bones and teeth fats insulation protein main source of energy vitamin D used for growth and repair ;;; 3 1(c) carbon, hydrogen and oxygen ; 1 1(d) (reducing) sugar ; 1 1(e) fibre ; 1 1(f) regular brushing / AVP ; 1 1(g) ingestion circled ; digestion circled ; 2

This question in 0654/32 Feb/March 2021

10 (a) A student writes a definition of an enzyme. The definition is not correct. ‘Enzymes are fats that function as chemical catalysts.’ Circle the two words in the student’s definition that are not correct. [2] (b) Enzymes are used to break down large molecules into smaller molecules. Table 10.1 shows some large molecules and the smaller molecules they are made from. Complete Table 10.1. Table 10.1 large molecules smaller molecules 1. starch glucose 2. … amino acids … fats 1. fatty acids 2. … [3] (c) List the three chemical elements that make up fats. 1 … 2 … 3 … [1] (d) Fig. 10.1 is a graph showing the enzyme activity at different temperatures of four different enzymes, A, B, C and D. C D B enzyme A activity –10 0 10 20 30 40 50 60 70 80 90 100 110 temperature / °C Fig. 10.1 Table 10.2 shows average temperatures in different environments. Table 10.2 type of environment average temperature / °C hot springs 50 arctic sea –2 hydrothermal vent region 95 deep sea 2 volcano sediment 75 (i) Describe the effect of temperature on the enzyme activity of enzyme B. Use data to support your answer. … … … … [2] (ii) Use Fig. 10.1 and Table 10.2 to identify the enzyme, A, B, C or D, found in bacteria that can survive in: hydrothermal vent regions … arctic seas … the same environment as enzyme C … [3] [Total: 11]

11 marks

Mark scheme: 10(a) fats ; chemical ; 2 10(b) glycogen ; protein ; glycerol ; 3 10(c) carbon hydrogen and oxygen ; 1 10(d)(i) as temperature increases enzyme activity increases then decreases ; peak / optimum at 33 °C ; 2 10(d)(ii) D ; A ; D ; 3

This question in 0654/32 Oct/Nov 2021

7 (a) Table 7.1 shows the number of different types of teeth in sheep and humans. Table 7.1 number of each type of teeth organism incisor canine pre-molar molar total human 8 4 8 12 32 sheep 8 0 6 6 (i) Calculate the total number of teeth for sheep. … [1] (ii) Place ticks (✓) in two boxes to show which statements are correct for the data in Table 7.1. Sheep have canine teeth. Sheep have the same number of pre-molar and molar teeth. A human has more incisor teeth than a sheep. A human has twice the number of molar teeth as a sheep. Humans have more incisor teeth than pre-molar teeth. [2] (b) The boxes on the left contain the different types of teeth. The boxes on the right contain the different functions of the types of teeth. Draw one line from each type of tooth to its correct function. Two types of teeth have the same function. type of tooth function incisor cut food canine grind food pre-molar pierce and tear food molar [3] (c) State the names of the two outermost layers of a tooth. 1 … 2 … [2] (d) Teeth are used for one type of digestion. State the name of this type of digestion. … [1] [Total: 9]

9 marks

Mark scheme: 7(a)(i) 20 ; 1 7(a)(ii) sheep have the same number of pre-molar and molar teeth ticked ; 2 humans have twice the number of molar teeth than sheep ticked ; 7(b) 3 incisor cut food canine grind food pre-molar pierce and tear food molar 1 or 2 teeth linked correctly ; 3 teeth linked correctly ; 4 teeth linked correctly ; 7(c) dentine ; 2 enamel ; 7(d) mechanical ; 1

This question in 0654/32 Oct/Nov 2022

10 (a) Fig. 10.1 is a diagram of the alimentary canal and associated organs in a human. A K B C J D H G E F Fig. 10.1 (i) Identify the letter in Fig. 10.1 that represents the part where: ingestion occurs … egestion occurs … mechanical digestion occurs … saliva is produced. … [4] (ii) State the name of the parts labelled D and H in Fig. 10.1. D … H … [2] (b) Table 10.1 shows some features of absorption and assimilation. Place ticks (3) in the boxes to show the features of each process. Table 10.1 feature process movement of digested movement into blood movement into cells food molecules absorption assimilation [3] (c) Draw a line to link each component to its dietary importance. One has been done for you. component dietary importance for growth and repair of tissues carbohydrates main source of energy fibre needed for bone growth iron needed for haemoglobin protein needed for insulation vitamin D prevents constipation [4] [Total: 13]

13 marks

Mark scheme: 10(a)(i) K ; 4 F ; K / C ; A ; 10(a)(ii) D – pancreas ; 2 H – gall bladder ; 10(b) 3 feature process movement of movement into movement into digested food blood cells molecules absorption   assimilation   ;;; 1 mark for each column 10(c) 4 for growth and repair of tissues carbohydrates main source of energy fibre needed for bone growth iron needed for haemoglobin protein needed for insulation vitamin D prevents constipation ;;;; 1 mark for each correct link

This question in 0654/33 Oct/Nov 2022

7 (a) Horses are herbivores. Define the term herbivore. … … … [2] (b) Fig. 7.1 is a photograph of the lower jaw of a horse. X Y Fig. 7.1 (i) The dental pattern of a horse is similar to that of humans. Identify the type of teeth labelled X and Y in Fig. 7.1. X … Y … [2] (ii) Identify the type of teeth found in a human jaw but not present in the jaw shown in Fig. 7.1. … [1] (iii) State the name of the type of digestion that takes place using teeth. … [1] (c) The statements describe some processes that occur in the alimentary canal. Place ticks (✓) to show all the statements that describe the process of absorption. food molecules are broken down so they become soluble food molecules become part of cells food molecules cross the wall of the small intestine food molecules enter the blood food molecules are taken in through the mouth [2] (d) Complete these sentences about biological molecules. Choose words or phrases from the list. Each word or phrase may be used once, more than once or not at all. amino acids fatty acids glycerol glycogen starch Proteins are made from smaller molecules called … . Glucose is used to make two larger molecules called … and … . Iodine solution is used to test for the presence of … . [4] [Total: 12]

12 marks

Mark scheme: 7(a) animal that gets its energy ; 2 from eating plants / AW ; 7(b)(i) X – premolars ; 2 Y – incisors ; 7(b)(ii) canines ; 1 7(b)(iii) mechanical ; 1 7(c) 2 food molecules cross the wall of the small intestine  food molecules enter the blood  ;; 2 ticks and 2 correct = 2 marks 3 ticks and 2 correct = 1 mark otherwise 0 marks 7(d) amino acids ; 4 glycogen ; starch ; starch ;

This question in 0654/31 Oct/Nov 2023

7 (a) Fig. 7.1 is a diagram of the alimentary canal and associated organs. A B C H G D E F Fig. 7.1 (i) Identify the letter in Fig. 7.1 that represents the part: where egestion occurs … where most absorption of food molecules occurs … that releases food into the small intestine … [3] (ii) State the names of parts A and C in Fig. 7.1. A … C … [2] (b) Circle the correct words in bold in the sentence to describe assimilation. Assimilation is the movement of digested / insoluble food molecules into the cells / genes of the body where they are used. [1] (c) (i) The boxes on the left show principal sources of some nutrients. The boxes on the right show the names of some nutrients. Draw lines to link each principal source with the main nutrient it supplies. carbohydrate butter fat rice protein tuna fish vitamin C [3] (ii) List the chemical elements that make up carbohydrates. … [1] (iii) Describe the importance of calcium in the diet. … … [1] [Total: 11]

11 marks

Mark scheme: 7(a)(i) F ; 3 D ; B ; 7(a)(ii) A – liver ; 2 C – pancreas ; 7(b) digested and cells ; 1 7(c)(i) 3 carbohydrate butter fat rice protein tuna fish vitamin C ;;; 7(c)(ii) carbon, hydrogen, oxygen ; 1 7(c)(iii) strengthen bones / teeth ; 1

This question in 0654/32 Oct/Nov 2023

7 (a) Enzymes are only active within a specific pH range. Table 7.1 shows the specific pH range for five different enzymes. Table 7.1 enzyme pH range enzyme is active A 1–5 B 5–9 C 7–12 D 2–3 E 10–12 Identify the enzyme(s) from Table 7.1 that are: only active in acidic conditions … active over the widest range of pH values … active at pH 8. … [3] (b) State one factor, other than pH, that affects enzyme activity. … [1] (c) Enzymes are proteins. Circle the elements that all enzymes contain. calcium carbon chlorine hydrogen magnesium nitrogen oxygen [1] (d) Table 7.2 lists some large nutrient molecules and the smaller molecules from which they are made. Complete Table 7.2. Table 7.2 large nutrient molecule smaller molecules that nutrients are made from fats and oils fatty acids and … proteins … 1. starch 2. … … [4] (e) Digested nutrients are absorbed by the body. Place ticks (3) in the boxes to show two correct statements about absorption. involves the breakdown of insoluble molecules to soluble molecules involves movement of digested food molecules into the blood involves movement of insoluble food molecules into cells occurs across the wall of the liver occurs across the wall of the intestine [2] [Total: 11]

11 marks

Mark scheme: 7(a) A and D ; 3 C ; B and C ; 7(b) temperature / AVP ; 1 7(c) carbon, hydrogen, oxygen, nitrogen circled ; 1 7(d) 4 large nutrient molecule smaller molecules that nutrients are made from fats and oils fatty acids and glycerol ; proteins amino acids ; 1. starch glucose ; 2. glycogen ; 7(e) 2 involves the breakdown of insoluble molecules to soluble molecules involves movement of digested food molecules into the blood  involves movement of insoluble food molecules into cells occurs across the wall of the liver occurs across the wall of the intestine  ;; 3 ticks and 2 correct = 1 mark 3 ticks and 1 correct = 0 marks 4 or more ticks = 0 marks

This question in 0654/33 Oct/Nov 2023

1 (a) Fig. 1.1 shows the parts of a human tooth. A B Fig. 1.1 (i) State the names of the parts labelled A and B in Fig. 1.1. A … B … [2] (ii) State the type of digestion that teeth are responsible for. … [1] (b) Cavities are holes in the teeth caused by poor care of teeth. A survey records the average number of cavities that 12‑year‑old school students have in one school. Every five years, the survey is repeated with another group of 12‑year‑olds in the same school. Fig. 1.2 shows a bar chart of the results. 5.0 4.5 4.0 3.5 3.0 average number of 2.5 cavities 2.0 1.5 1.0 0.5 0.0 1985 1990 1995 2000 2005 2010 2015 year Fig. 1.2 (i) Calculate the percentage decrease in the average number of cavities between 1985 and 2015 in Fig. 1.2. average number of cavities in 1985 … average number of cavities in 2015 … percentage decrease = … % [2] (ii) Suggest three reasons for the trend seen in Fig. 1.2. 1 … … 2 … … 3 … … [3] (c) The mouth has a good supply of blood. List two main components of blood. 1 … 2 … [2] [Total: 10]

10 marks

Mark scheme: 1(a)(i) A – enamel ; B – pulp (cavity) ; 2 1(a)(ii) mechanical ; 1 1(b)(i) 4.6 and 0.8 ; ((3.8 / 4.6)  100) = 83 (%) ; 2 1(b)(ii) any three from: improvement in dental care by people ; improvement in dental, care / technology ; reduction in consumption of sugar / more calcium in diet ; ref to education ; addition of fluoride to drinking water / toothpaste ; 3 1(c) any two from: red blood cells ; white blood cells ; plasma ; platelets ; 2

This question in 0654/31 May/June 2024

7 (a) Table 7.1 shows some information about five different enzymes. Table 7.1 pH value where the pH range where the enzyme enzyme is the most enzyme is active active A 4.5–8.5 6.5 B 1.0–4.0 2.5 C 7.0–11.0 9.0 D 1.0–3.0 1.5 E 6.0–8.5 7.0 (i) Identify the enzyme(s) from Table 7.1 that: • have the widest pH range of activity … and … • is active at pH 5.5 … • is most active in alkaline conditions. … [3] (ii) State one other factor, apart from pH, that affects the activity of enzymes. … [1] (b) Circle two words that are used to describe enzymes. carbohydrates catalysts fats hormones proteins solvents [2] (c) The list shows some parts of the alimentary canal and associated organs. anus gall bladder mouth oesophagus pancreas small intestine Choose words from the list to identify where each process occurs. Each word may be used once, more than once or not at all. mechanical digestion … egestion … ingestion … [3] (d) Describe one similarity between absorption and assimilation. … … … [1] [Total: 10]

10 marks

Mark scheme: 7(a)(i) A AND C ; 3 A ; C ; 7(a)(ii) temperature / AVP ; 1 7(b) proteins circled ; 2 catalysts circled ; 7(c) mouth ; 3 anus ; mouth ; 7(d) both involve the movement of, digested food / molecules / soluble nutrients ; 1

This question in 0654/32 Oct/Nov 2024

7 (a) Table 7.1 shows some information about five different enzymes. Table 7.1 pH value where the pH range where the enzyme enzyme is the most enzyme is active active A 4.5–8.5 6.5 B 1.0–4.0 2.5 C 7.0–11.0 9.0 D 1.0–3.0 1.5 E 6.0–8.5 7.0 (i) Identify the enzyme(s) from Table 7.1 that: • have the widest pH range of activity … and … • is active at pH 5.5 … • is most active in alkaline conditions. … [3] (ii) State one other factor, apart from pH, that affects the activity of enzymes. … [1] (b) Circle two words that are used to describe enzymes. carbohydrates catalysts fats hormones proteins solvents [2] (c) The list shows some parts of the alimentary canal and associated organs. anus gall bladder mouth oesophagus pancreas small intestine Choose words from the list to identify where each process occurs. Each word may be used once, more than once or not at all. mechanical digestion … egestion … ingestion … [3] (d) Describe one similarity between absorption and assimilation. … … … [1] [Total: 10]

10 marks

Mark scheme: 7(a)(i) A AND C ; 3 A ; C ; 7(a)(ii) temperature / AVP ; 1 7(b) proteins circled ; 2 catalysts circled ; 7(c) mouth ; 3 anus ; mouth ; 7(d) both involve the movement of, digested food / molecules / soluble nutrients ; 1

This question in 0654/33 Oct/Nov 2024

2 (a) The boxes on the left show different processes that occur in the human body. The boxes on the right show the descriptions of some of the processes. Draw one line from each process to its correct description. process description the uptake and use of nutrients by cells egestion the taking of substances, e.g. food and drink, into the body ingestion the removal of undigested food from the body as faeces digestion the movement of nutrients from the assimilation intestine into the blood the breakdown of food [4] (b) (i) Large biological molecules are made from smaller molecules. Complete the sentences about different biological molecules. Large protein molecules are made from smaller molecules called … . The elements in protein molecules are carbon, … , oxygen and … . Glycogen is a large molecule made from smaller molecules called … . [3] (ii) Reducing sugars are small biological molecules. State the name of the reagent used to test for reducing sugars. Give the observation for a positive result. reagent … observation for a positive result … … [2] [Total: 9]

9 marks

Mark scheme: 2(a) 4 ; ; ; ; 2(b)(i) amino acids ; 3 hydrogen (and) nitrogen ; glucose ; 2(b)(ii) add Benedict’s (and heat) ; 2 (brick) red / orange /yellow/ green ;

This question in 0654/32 Feb/March 2025

2 (a) Fig. 2.1 is a diagram of the human digestive system. A B G C D F E Fig. 2.1 (i) Using letters A–G in Fig. 2.1, identify: the anus … the liver. … [2] (ii) Using letters A–G in Fig. 2.1, identify an organ where these processes occur: absorption … digestion. … [2] (b) Complete the sentences about digestion. The breakdown of food into smaller pieces is called … digestion. This increases the surface area of the food. The food is then broken down from large … molecules to small … molecules. This is called … digestion and produces molecules that can be absorbed. [4] (c) Table 2.1 shows the nutrition label from a bag of rice. Table 2.1 typical values nutrient per 235 g bag of rice / g fats and oils 2.1 carbohydrate 76.6 fibre 1.4 protein 8.5 (i) Use Table 2.1 to calculate the percentage of protein in the rice. … % [2] (ii) Table 2.1 gives four types of nutrients needed for a healthy diet. State one other type of nutrient needed for a healthy diet. … [1] [Total: 11]

11 marks

Mark scheme: 2(a)(i) E ; 2 G ; 2(a)(ii) D or F ; 2 A or B or F ; 2(b) physical / mechanical ; 4 insoluble ; soluble ; chemical ; 2(c)(i) 8.5 and 235 ; 2 3.6 ; 2(c)(ii) vitamins / minerals / water ; 1

This question in 0654/31 May/June 2025

1 (a) Fig. 1.1 is a diagram of the alimentary canal and associated organs. E A B C D Fig. 1.1 (i) Identify the parts labelled A, C and E in Fig. 1.1. A … C … E … [3] (ii) Egestion occurs through structure D. Complete the sentence to describe egestion. Egestion is the removal of … food from the body as … . [2] (iii) State the name of a hormone produced by the part labelled B. … [1] (b) (i) Reducing sugars are absorbed into the blood from the alimentary canal. Describe the test for reducing sugar and the colour change observed for a positive result. test … colour change: starting colour … final colour … [3] (ii) Complete the word equation for photosynthesis: … + carbon dioxide … + … [2] (iii) The carbon dioxide needed for photosynthesis diffuses into the plant through the stomata. Place ticks (3) in two boxes to show the statements that correctly describe diffusion. Diffusion is described as the net movement of particles. Diffusion is the result of random movement of particles. Diffusion is the movement of particles from a lower to higher concentration. Diffusion is the movement of particles up a concentration gradient. In diffusion the particles always move through a partially permeable membrane. [2] [Total: 13]

13 marks

Mark scheme: Question Answer Marks 1(a)(i) A – stomach ; 3 C – large intestine ; E – gall bladder ; 1(a)(ii) undigested ; 2 faeces ; 1(a)(iii) insulin ; 1 1(b)(i) (heat with) Benedict’s (solution) ; 3 (starting colour) blue ; (final colour) red / orange / yellow / green ; 1(b)(ii) water + (carbon dioxide) → oxygen + glucose 2 1 mark left hand side correct 1 mark right hand side correct 1(b)(iii) 2 1 mark for each correct answer 3 boxes ticked – 2 correct – 1 mark 3 boxes ticked – 1 correct – 0 marks 4 boxes ticked – 0 marks

This question in 0654/33 Oct/Nov 2025