CIE iGCSE Co-Ordinated Science B7.2 Digestive system Exam Style Questions Paper 3
Question
(a) Table 7.1 shows some information about five different enzymes.
(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. …………………………………………
(ii) State one other factor, apart from pH, that affects the activity of enzymes.
(b) Circle two words that are used to describe enzymes.
carbohydrates catalysts fats
hormones proteins solvents
(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 …………………………………………
(d) Describe one similarity between absorption and assimilation.
▶️Answer/Explanation
Ans : 7(a)(i) A AND C ;
A ;
C ;
7(a)(ii) temperature / AVP ;
7(b) proteins circled ;
catalysts circled ;
7(c) mouth ;
anus ;
mouth ;
7(d) both involve the movement of, digested food / molecules / soluble nutrients ;
Question
(a) Fig. 1.1 shows the parts of a human tooth.
(i) State the names of the parts labelled A and B in Fig. 1.1.
(ii) State the type of digestion that teeth are responsible for.
(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.
(i) Calculate the percentage decrease in the average number of cavities between 1985 and 2015 in Fig. 1.2.
(ii) Suggest three reasons for the trend seen in Fig. 1.2.
1 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
3 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(c) The mouth has a good supply of blood.
List two main components of blood.
1 ………………………………………………………………………………………………………………………………
2 ………………………………………………………………………………………………………………………………
▶️Answer/Explanation
Ans : 1(a)(i)
A – enamel ;
B– pulp (cavity) ;
1(a)(ii) mechanical ;
1(b)(i) 4.6 and 0.8 ;
((3.8 / 4.6) × 100) = 83 (%) ;
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 ;
1(c) any two from:
red blood cells ;
white blood cells ;
plasma ;
platelets ;
Question
(a) Fig. 7.1 is a diagram of the alimentary canal and associated organs.
(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 ………………………….
(ii) State the names of parts A and C in Fig. 7.1.
A ……………………………………………………………………………………………………………………….
C ……………………………………………………………………………………………………………………….
(b) 
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.
(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.
(ii) List the chemical elements that make up carbohydrates.
…………………………………………………………………………………………………………………….
(iii) Describe the importance of calcium in the diet.
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans: 7(a)(i) F ;
D ;
B ;
7(a)(ii) A – liver ;
C – pancreas ;
7(b) digested and cells ;
7(c)(i)
7(c)(ii) carbon, hydrogen, oxygen ;
7(c)(iii) strengthen bones / teeth ;
Question
(a) Fig. 1.1 is a diagram of the alimentary canal and associated organs.
(i) State the letter in Fig. 1.1 that identifies where:
most absorption occurs …………………………………..
egestion occurs …………………………………..
ingestion occurs …………………………………..
saliva is produced. …………………………………..
(ii) State the names of the parts labelled D and H in Fig. 1.1.
D …………………………………………………………………………
H …………………………………………………………………………
(iii) Complete the sentence to define the term digestion.
Digestion is the ………………………………………… of large, insoluble food molecules into small, water-soluble molecules using mechanical and ………………………………………… processes.
(b) The boxes on the left show some nutrients.
The boxes on the right show some principal sources of nutrients.
Draw one straight line from each nutrient to its principal source.
nutrient principal source
(c) Describe the dietary importance of iron.
▶️Answer/Explanation
Ans : 1(a)(i) F ;
E ;
J ;
A ;
1(a)(ii) D – pancreas ;
H – liver ;
1(a)(iii) breakdown ;
chemical ;
1(b) 
1(c) making haemoglobin / prevent anaemia / AVP ;
Question
(a) Fig. 10.1 is a diagram of the alimentary canal and associated organs in a human. (Sub-topic – B7.2)
(i) Identify the letter in Fig. 10.1 that represents the part where:
- ingestion occurs – K
- egestion occurs – F
- mechanical digestion occurs – K or C
- saliva is produced – A
▶️Answer/Explanation
K; F; K/C; A
(ii) State the name of the parts labelled D and H in Fig. 10.1.
- D – pancreas
- H – gall bladder
▶️Answer/Explanation
D – pancreas; H – gall bladder
(b) Table 10.1 shows some features of absorption and assimilation.
Place ticks (✓) in the boxes to show the features of each process. (Sub-topic – B7.2)
| process | feature | ||
|---|---|---|---|
| movement of digested food molecules | movement into blood | movement into cells | |
| absorption | |||
| assimilation | |||
▶️Answer/Explanation
Here is the completed table with ticks (✓):
| process | feature | ||
|---|---|---|---|
| movement of digested food molecules | movement into blood | movement into cells | |
| absorption | ✓ | ✓ | |
| assimilation | ✓ | ✓ | |
(c) Draw a line to link each component to its dietary importance. (Sub-topic –B7.1)
One has been done for you.
- carbohydrates – main source of energy
- fibre – prevents constipation
- iron – needed for haemoglobin
- protein – for growth and repair of tissues
- vitamin D – needed for bone growth
▶️Answer/Explanation
carbohydrates – main source of energy; fibre – prevents constipation; iron – needed for haemoglobin; protein – for growth and repair of tissues; vitamin D – needed for bone growth
Question
1. (a) (i) State which animal in Table 1.1 has the largest number of teeth.
▶️Answer/Explanation
Answer: fox
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The animal with the largest number of teeth in Table 1.1 is the fox, which has 42 teeth.
1. (a) (ii) Calculate the difference in the number of teeth between a human and an elephant as shown in Table 1.1.
▶️Answer/Explanation
Answer: 6
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The difference in the number of teeth between a human (32 teeth) and an elephant (26 teeth) is 32 – 26 = 6.
1. (b) Circle the name of the outermost layer of a tooth.
▶️Answer/Explanation
Answer: enamel
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The outermost layer of a tooth is called the enamel, which protects the tooth from decay.
1. (c) State the type of teeth responsible for grinding food.
▶️Answer/Explanation
Answer: molar / pre molar
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The molars and premolars are responsible for grinding food during the chewing process.
1. (d) Describe one way to take care of teeth.
▶️Answer/Explanation
Answer: brushing / using toothpaste / (regular) visits to dentist / consume less sugary food or drink
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: One way to take care of teeth is by brushing regularly with toothpaste, which helps remove plaque and prevent tooth decay. Regular visits to the dentist and reducing sugary food intake also help maintain dental health.
1. (e) (i) Identify the letter from Fig. 1.1 that represents where:
egestion occurs ……
the most absorption occurs ……
ingestion occurs. ……
▶️Answer/Explanation
Answer: D ; E ; H
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: In Fig. 1.1, egestion occurs at D, the most absorption occurs at E, and ingestion occurs at H.
1. (e) (ii) State the name of part C in Fig. 1.1.
▶️Answer/Explanation
Answer: pancreas
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: Part C in Fig. 1.1 is the pancreas, which produces digestive enzymes and insulin.
1. (f) Complete the definition of digestion.
Digestion is the …… of large, insoluble food molecules into small, water-soluble molecules using …… and chemical processes.
▶️Answer/Explanation
Answer: break(ing) down ; mechanical
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: Digestion is the process of breaking down large, insoluble food molecules into small, water-soluble molecules using mechanical and chemical processes.
1. (g) After the food is digested, nutrients pass into the blood. State the part of the blood that transports soluble nutrients.
▶️Answer/Explanation
Answer: plasma
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The part of the blood that transports soluble nutrients is the plasma, which is the liquid component of blood.
Question
(a) Fig. 10.1 is a diagram of the human alimentary canal and associated organs.
(i) Label Fig. 10.1 on the answer lines provided.
Choose words from the list:
- anus
- large intestine
- mouth
- pancreas
- small intestine
- stomach
(ii) Different processes occur in the alimentary canal. Complete Table 10.1 using words from the list in (a)(i).
| Process | One part of the alimentary canal where process occurs |
|---|---|
| ingestion | |
| egestion | |
| mechanical digestion |
▶️Answer/Explanation
(i) Labels for Fig. 10.1:
- mouth
- stomach
- pancreas
- small intestine
(ii) Table 10.1:
| Process | One part of the alimentary canal where process occurs |
|---|---|
| ingestion | mouth |
| egestion | anus |
| mechanical digestion | mouth / stomach |
(b) Describe the role of chemical digestion in the alimentary canal.
▶️Answer/Explanation
Chemical digestion is the process by which large, insoluble food molecules are broken down into smaller, soluble molecules that can be absorbed into the bloodstream. This process is facilitated by enzymes, which are biological catalysts that speed up chemical reactions without being consumed in the process. For example, amylase breaks down starch into simple sugars, proteases break down proteins into amino acids, and lipases break down fats into fatty acids and glycerol. These smaller molecules can then be absorbed through the walls of the small intestine and transported to cells throughout the body for use as energy or building blocks.
(c) The boxes contain the beginnings and the endings of some sentences. Join one sentence beginning to one sentence ending to define the term assimilation.
▶️Answer/Explanation
Assimilation is the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.