O Level Biology Cells Biomolecules Quiz

O-Level Biology Quiz - Cells Biomolecules

Name: _________________ Class: _______ Date: _________

Score: _____ / 50 Duration: 45 minutes

Instructions:

• Answer all questions in the spaces provided
• Show your working for calculation questions
• Use appropriate biological terminology

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Section A: Short Answer Questions [20 marks]

1. Name the process by which large molecules are built from smaller subunits in living organisms. [1]

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2. State the chemical elements present in proteins that are not found in carbohydrates. [1]

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3. Complete the word equation for aerobic respiration: [2]

Glucose + _________________ → _________________ + Water + Energy

4. Name the organelle where aerobic respiration takes place in plant and animal cells. [1]

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5. State two functions of the cell membrane. [2]

(a) _________________________________

(b) _________________________________

6. Name the type of transport that moves substances against their concentration gradient. [1]

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7. Complete the following sentence about enzyme specificity: [2]

Enzymes are specific because the shape of the _________________ is complementary to the shape of the _________________.

8. State the optimum pH for pepsin, the protein-digesting enzyme in the stomach. [1]

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9. Name two end products of protein digestion. [2]

(a) _________________________________

(b) _________________________________

10. Give the food test that would produce a brick-red precipitate. [1]

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11. State what happens to excess amino acids in the liver. [2]

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12. Name the process by which water moves across a partially permeable membrane. [1]

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13. State two differences between prokaryotic and eukaryotic cells. [2]

(a) _________________________________

(b) _________________________________

14. Name the carbohydrate stored in plant cells. [1]

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Section B: Structured Questions [30 marks]

15. The diagram shows a plant cell as seen under an electron microscope.

Generated diagram for this question.

(a) Name organelles A and B. [2]

A: _________________________________

B: _________________________________

(b) Explain how organelle A is adapted for its function. [3]

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(c) State one function of organelle B that does not occur in animal cells. [1]

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16. An investigation was carried out to study the effect of temperature on enzyme activity. The results are shown in the table below.

Temperature (°C)	Rate of reaction (arbitrary units)
10	12
20	25
30	45
40	60
50	35
60	8

(a) Plot a graph of these results on the grid below. [3]

[Grid would be provided]

(b) State the optimum temperature for this enzyme. [1]

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(c) Explain why the rate of reaction decreases above the optimum temperature. [2]

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(d) Predict the rate of reaction at 0°C. Give a reason for your answer. [2]

Rate: _________________________________

Reason: _________________________________

17. Describe the process of active transport and explain why it is important for root hair cells. [6]

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18. A student investigated osmosis using potato strips in different concentrations of sugar solution. The results are shown below.

Sugar concentration (%)	Change in mass (%)
0	+15
5	+8
10	+2
15	-3
20	-12

(a) Explain why the potato strips gained mass in 0% sugar solution. [3]

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(b) Estimate the concentration of sugar solution that would cause no change in mass. Explain your answer. [2]

Concentration: _________________________________

Explanation: _________________________________

(c) Explain what would happen to plant cells if they were placed in a solution with a very high concentration of salt. [3]

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