REPUBLIC OF DISTRICT COMPREHENSIVE Date:
RWANDA 26/03/ 2025
EXAMINATION
Duration: 3h
SECOND TERM
Max:
SCHOOL YEAR: 2024/2025 100 Marks
SUBJECT: Biology & Health sciences
LEVEL: Ordinary Level
WESTERN
PROVINCE Class: Senior two
RUBAVU DISTRICT
INSTRUCTIONS:
This paper consists of three sections A, B and C
Section A: Attempt all questions (55 marks)
Section B: Attempt only 3 questions (30 marks)
Section C is compulsory (15 marks)
SECTION A: ATTEMPT ALL QUESTIONS
Q1. Which one of the following describes osmosis? /2 marks
a) Movement of sugar molecules.
b) Movement of water molecules.
c) Movement of sugar and salt molecules.
d) Evaporation of water.
Q2 Glucose is known as a reducing sugar because: /2 marks
a) It is carbohydrate.
b) It is a hexose sugar.
c) It reduces copper (II) sulphate to copper (I) oxide.
d) It is a disaccharide.
Q3. Enzymes are ……………. in nature. /2 marks
a) Starch.
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b) Protein.
c) Carbohydrate.
d) Lipid.
Q4. In which part of the respiratory system, gaseous exchange takes place? /2 marks
a) Alveoli.
b) Pharynx.
c) Larynx.
d) Trachea.
Q5. Amylase is a digestive enzyme found in the saliva. Which of the following food substances does it
breakdown? /2 marks
a) Glucose.
b) Starch.
c) Protein.
d) Carbohydrate.
Q6. The chemical test for Vitamin C is………. /2 marks
a) Biuret test
b) Ethanol test
c) DCPIP test
d) Benedict’s test
Q7. Match the following ecological terms with their definitions /5 marks
Ecological term Meaning
i. The total number of organisms of the same species living together
a. Community in a specific area at a certain time
ii. A place where organism lives
b. Ecosystem
iii. A number of species interacting in a locality
c. Food web
iv. A nutrional interrelationship of organism
d. Habitat
v. Interaction of organism with each other and with their
e. Population environment
Q8. Copy and complete the following table /8 marks
Animal Phylum Class
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Cockroach
Toad
Centipede
Elephant
Q9. Match the following organs of urinary system to their function. /4 marks
Organ Function
a. Ureter 1. Where urine is produced
b. Kidney 2. urine is stored here
c. urethra 3. bring urine from the kidney to the bladder
d. urinary bladder 4. urine is eliminated from the body through this tube
Q10. plants need water which often has mineral salts dissolved in it
a) what do plants make from the following minerals /2 marks
i. Magnesium
ii. Nitrates
b) Give two reasons why water is important to plants /2 marks
c) (i) in which vessel does water travel up through the plant /1 mark
(ii) in which vessel does sugar travel through the plant /1mark
Q11. (a) State the characteristics of a good gas exchange. /3 marks
(b) how does the diaphragm help during breathing /2 marks
(c) Give the difference between respiration and breathing /2 marks
Q12. Use the diagram of the cross-section through the leaf to answer the questions
a. Indicate on the diagram the following: stomata, spongy mesophyll layer, palisade layer and cuticle
/4 marks
b. Which cell type absorbs most carbon dioxide during the day? /1 mark
c. State the role of the part labelled D in photosynthesis /1 mark
d. Of what importance is the shape of cell type C in photosynthesis? /1 mark
Q13. a) What do you understand by Xerophytes /1 mark
b) Describe how Xerophytes are adapted to their environment /3 marks
Q14. State the importance of transpiration in plants /2 marks
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SECTION B: CHOOSE ANY THREE QUESTIONS
Q15. (a) Vertebrate animals are divided into five group or classes. Name them /5marks
(b) From the list provided in b above identify the group in which the following animal are classified
i. Warm- blooded animals /5marks
ii. Cold-blooded animals
Q16. a. Photosynthesis is a process that takes place in plant
i. What a type of energy is needed for this process /1mark
ii. What substance(s) in the plant absorbs this energy /1mark
iii. In which part of the plant cell does photosynthesis takes place? / 1mark
iv. Write the chemical equation for photosynthesis /3marks
b. describes ways you would use to speed up the rate of photosynthesis /4marks
Q17. Enzymes are biological catalyst
a. Whare the types of enzymes /2marks
b. What are the major characteristics of enzymes /5marks
c. Match the following enzymes with their substrate /3marks
i. Lipase 1. starch
ii. Protease 2. lipids
iii. Amylase 3. proteins
Q18. Study the following diagram and answer the asked questions:
a) what the name given to the above diagram /1mark
b) what do the arrows on the diagram mean /1mark
c) green plant are the producers, what does this mean /2marks
d) name two primary consumers from the above diagram /2marks
e) name two carnivores from the above diagram /2marks
f) which trophic level does Lion belong to /1mark
g) where do green plants get their energy /1mark
Q19. Study the diagram below representing organism in the phylum of arthropoda
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a) State any two common characteristics of arthropoda /2 Marks
b) Suggest the classes of Bee, Tick, Crab, Millipede /4 Marks
c) State two benefits and dangers of animal in the same class as Bee /4 Marks
SECTION C: COMPULSORY QUESTIONS
Q20. The table below shows tests for proteins using Biurets test on different food samples. Analyse the table
and complete the observation and deduction. (15 marks)
Test procedure Observation Deductions
3
(i) Milk + 1cm of 1% copper sulphate solution +
sodium hydroxide
(ii) Lemon juice + 1cm3 of 1% copper sulphate
solution + sodium hydroxide
(iii) Egg albumen + 1cm3 of 1% copper sulphate
solution + sodium hydroxide.
(iv) Suspension of maize+ 1cm3 of 1% copper
sulphate solution + sodium hydroxide
(v) Sugar cane juice + 1cm3 of 1% copper sulphate
solution + sodium hydroxide
a) When testing for non-reducing sugars, give one reason why each of the following was added.
(i) Dilute hydrochloric acid /1 mark
(ii) Sodium hydrochloric solution /1 mark
b) Which reagent could be used if the food sample is being tested for the presence of starch? /1 mark
END
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