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Secondary 3 Biology Cells Biomolecules Quiz
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Questions
Secondary 3 Biology Quiz - Cells Biomolecules
Name: _________________ Class: _______ Date: ___________ Score: ____/50
Duration: 45 minutes
Total Marks: 50
Instructions: Answer all questions. Write your answers in the spaces provided.
Section A: Multiple Choice Questions [10 marks]
Choose the best answer for each question. Write the letter in the box provided.
1. An actively growing cell is supplied with radioactive amino acids. Which cell component would first show an increase in radioactivity?
A) Nucleus
B) Rough endoplasmic reticulum
C) Golgi apparatus
D) Mitochondria
Answer: [ ]
2. Which of the following best describes the relationship between cells, tissues, organs and organ systems?
A) Cells → Organs → Tissues → Organ systems
B) Cells → Tissues → Organs → Organ systems
C) Tissues → Cells → Organs → Organ systems
D) Organs → Tissues → Cells → Organ systems
Answer: [ ]
3. The diagram shows an animal cell. Which part is involved in the modification and packaging of proteins?
[Assume diagram shows labeled organelles 1-6]
A) 1 (Nucleus)
B) 3 (Rough ER)
C) 4 (Golgi apparatus)
D) 6 (Mitochondria)
Answer: [ ]
4. Which enzyme would be most affected by a change in pH from 7 to 2?
A) Amylase (works in mouth, pH 7)
B) Pepsin (works in stomach, pH 2)
C) Maltase (works in small intestine, pH 8)
D) Catalase (works in liver, pH 7)
Answer: [ ]
5. A student tests a food sample with Benedict's solution and observes a brick-red precipitate. This indicates the presence of:
A) Starch
B) Protein
C) Reducing sugar
D) Lipids
Answer: [ ]
Section B: Structured Questions [25 marks]
6. The diagram shows four different types of cells.
[Assume diagram shows: Cell A = Red blood cell, Cell B = Root hair cell, Cell C = Nerve cell, Cell D = Sperm cell]
(a) Which cell is best adapted for rapid transmission of electrical signals? [1]
Answer: _________________
(b) Explain two ways in which Cell A is adapted to its function of transporting oxygen. [4]
Adaptation 1: ________________________________________________
Explanation: ________________________________________________
Adaptation 2: ________________________________________________
Explanation: ________________________________________________
(c) Cell B is found in plant roots. Describe how its structure helps it absorb water and mineral salts efficiently. [3]
Structure: ________________________________________________
Function: ________________________________________________
7. A student investigated the effect of temperature on catalase enzyme activity using the apparatus shown below.
[Assume diagram shows test tube with hydrogen peroxide and catalase, with gas collection tube]
The table shows the results:
| Temperature (°C) | Volume of oxygen gas collected in 2 minutes (cm³) |
|---|---|
| 10 | 5 |
| 20 | 12 |
| 30 | 28 |
| 40 | 35 |
| 50 | 20 |
| 60 | 8 |
| 70 | 2 |
(a) What is the optimum temperature for catalase activity? [1]
Answer: _________________ °C
(b) Explain the results observed between 10°C and 40°C. [3]
(c) Explain why the enzyme activity decreases rapidly after 40°C. [3]
(d) Suggest one way the student could improve the reliability of this investigation. [1]
8. Compare and contrast diffusion and active transport. [6]
(a) State two similarities between diffusion and active transport. [2]
Similarity 1: ________________________________________________
Similarity 2: ________________________________________________
(b) State two differences between diffusion and active transport. [4]
| Feature | Diffusion | Active Transport |
|---|---|---|
| Energy requirement | ||
| Direction of movement |
9. The diagram shows a plant cell and an animal cell.
[Assume diagram shows labeled plant and animal cells with structures A-F]
(a) Name the structures labeled A and B that are found only in plant cells. [2]
A: _________________
B: _________________
(b) Explain the function of structure A in the plant cell. [2]
Section C: Extended Response [15 marks]
10. Describe and explain how a red blood cell and a root hair cell are adapted to their specific functions. [8]
11. A student placed some potato chips in different concentrations of salt solution and measured their mass before and after 30 minutes.
| Salt concentration (%) | Initial mass (g) | Final mass (g) | Change in mass (g) |
|---|---|---|---|
| 0 | 5.0 | 5.8 | +0.8 |
| 0.5 | 5.0 | 5.3 | +0.3 |
| 1.0 | 5.0 | 5.0 | 0 |
| 1.5 | 5.0 | 4.6 | -0.4 |
| 2.0 | 5.0 | 4.2 | -0.8 |
(a) Explain the results observed in the 0% salt solution. [3]
(b) What can you conclude about the concentration of the cell sap in the potato cells? Explain your answer. [4]
END OF QUIZ
Answers
Secondary 3 Biology Quiz - Cells Biomolecules (Answer Key)
Total Marks: 50
Section A: Multiple Choice Questions [10 marks]
1. B - Rough endoplasmic reticulum
Explanation: Radioactive amino acids are first incorporated into proteins at ribosomes on the rough ER, before being processed by the Golgi apparatus.
2. B - Cells → Tissues → Organs → Organ systems
Explanation: This represents the correct hierarchical organization of biological structures from smallest to largest.
3. C - Golgi apparatus
Explanation: The Golgi apparatus modifies and packages proteins received from the rough ER before transport to their final destinations.
4. A - Amylase
Explanation: Amylase works optimally at pH 7 (neutral). A change to pH 2 (acidic) would denature this enzyme, while pepsin naturally works at pH 2.
5. C - Reducing sugar
Explanation: Benedict's solution turns brick-red/orange when heated with reducing sugars like glucose, fructose, or maltose.
Section B: Structured Questions [25 marks]
6. (a) Cell C (Nerve cell) [1 mark]
6. (b) [4 marks total - 2 marks per adaptation]
Sample answer:
- Adaptation 1: Biconcave/disc shape
- Explanation: Increases surface area to volume ratio for efficient oxygen loading and unloading
- Adaptation 2: No nucleus or organelles
- Explanation: Provides more space for haemoglobin to carry oxygen
Alternative acceptable adaptations: flexible membrane for passage through capillaries, contains haemoglobin
6. (c) [3 marks]
- Structure: Long projection/hair-like extension from cell surface [1]
- Function: Increases surface area for absorption of water and mineral salts [2]
7. (a) 40°C [1 mark]
7. (b) [3 marks] As temperature increases from 10°C to 40°C, enzyme activity increases because:
- Molecules have more kinetic energy [1]
- More frequent collisions between enzyme and substrate [1]
- Faster rate of enzyme-substrate complex formation [1]
7. (c) [3 marks] After 40°C, enzyme activity decreases because:
- High temperature causes enzyme denaturation [1]
- Active site shape changes [1]
- Substrate can no longer bind to active site/enzyme becomes non-functional [1]
7. (d) [1 mark] Sample answers:
- Repeat the experiment multiple times and calculate average
- Use same volume/concentration of hydrogen peroxide
- Use same amount of catalase
- Control other variables (pH, pressure)
8. (a) [2 marks - 1 mark each] Sample similarities:
- Both involve movement of substances across cell membranes
- Both are essential for cell survival/function
- Both can be selective for certain substances
8. (b) [4 marks - 2 marks per difference]
| Feature | Diffusion | Active Transport |
|---|---|---|
| Energy requirement | No energy/ATP required (passive) | Requires energy/ATP |
| Direction of movement | Down concentration gradient | Against concentration gradient |
Alternative differences: speed, use of carrier proteins, selectivity
9. (a) [2 marks]
- A: Cell wall [1]
- B: Chloroplast [1]
9. (b) [2 marks] Function of cell wall:
- Provides structural support/protection [1]
- Prevents over-expansion when cell absorbs water/maintains cell shape [1]
Section C: Extended Response [15 marks]
10. [8 marks total]
Expected content for full marks:
Red Blood Cell (4 marks):
- Function: Transport oxygen from lungs to body tissues [1]
- Adaptation 1: Biconcave shape increases surface area for gas exchange [1]
- Adaptation 2: No nucleus provides more space for haemoglobin [1]
- Adaptation 3: Flexible membrane allows passage through narrow capillaries [1]
Root Hair Cell (4 marks):
- Function: Absorb water and mineral salts from soil [1]
- Adaptation 1: Hair-like projection increases surface area for absorption [1]
- Adaptation 2: Thin cell wall allows rapid diffusion [1]
- Adaptation 3: Many mitochondria provide energy for active transport of minerals [1]
Marking notes: Award marks for clear structure-function relationships. Accept alternative valid adaptations.
11. (a) [3 marks] In 0% salt solution (pure water):
- Water moves into potato cells by osmosis [1]
- Water potential outside cell is higher than inside cell [1]
- Cells gain water and increase in mass [1]
11. (b) [4 marks] Conclusion and explanation:
- The cell sap concentration is equivalent to approximately 1.0% salt solution [1]
- This is where there is no net change in mass (equilibrium point) [1]
- At this concentration, water potential inside and outside cells is equal [1]
- No net movement of water occurs by osmosis [1]
Marking Guidelines:
- Award marks for scientific accuracy and appropriate use of terminology
- Accept alternative valid explanations that demonstrate understanding
- Deduct marks for incorrect scientific terminology or concepts
- Award partial marks for incomplete but correct responses