Secondary 4 Pure Biology Cells Biomolecules Quiz

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Secondary 4 Pure Biology Quiz - Cells Biomolecules

Name: ____________________
Class: ____________________
Date: ____________________
Score: ________ / 55

Duration: 60 Minutes
Total Marks: 55 Marks

Instructions:

• Answer all questions in the spaces provided.
• Use a black or blue pen.
• For calculations, show all working clearly.

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Section A: Cell Structure and Organisation (15 Marks)

1. Name the specific cells in the root epidermis through which water is absorbed from the soil. [1]

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2. State the primary function of the Golgi body in a eukaryotic cell. [1]

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3. Which organelle is the site of aerobic respiration and ATP production? [1]

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4. Compare a typical plant cell and an animal cell by stating two structures found in a plant cell but absent in an animal cell. [2] i. ________________________________________________________________________ ii. _______________________________________________________________________

5. Red blood cells are specialised for the transport of oxygen. Explain how the absence of a nucleus is an adaptation for this function. [2]

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6. A muscle cell contains a significantly higher number of mitochondria compared to a skin cell. Explain why this is necessary. [2]

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7. Identify the organelle responsible for protein synthesis. [1]

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8. Describe the function of the cell wall in plant cells. [2]

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9. Which organelle contains the genetic material (DNA) and controls the activities of the cell? [1]

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10. State the function of the large central vacuole in a plant cell. [2]

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Section B: Movement of Substances (20 Marks)

11. Define the term diffusion. [2]

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12. Explain the difference between diffusion and osmosis. [2]

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13. A red blood cell is placed in a solution with a very low water potential (hypertonic). (a) Describe the direction of water movement. [1]

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    (b) State the resulting condition of the red blood cell. [1]

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14. If the blood glucose concentration is very high, there is a decrease in the water potential of the blood. Explain how this may lead to the damage of red blood cells. [3]

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15. Define active transport and state whether it requires energy. [2]

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16. Explain why active transport is necessary for the uptake of mineral ions by root hair cells from the soil. [3]

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17. In the small intestine, glucose is absorbed into the villi. Explain the process involved when the glucose concentration in the villi is already higher than in the intestinal lumen. [3]

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18. A plant cell is placed in distilled water. Describe the change in the cell and explain why the cell does not burst. [3]

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19. Give one example of a real-world application of osmosis in food preservation. [1]

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20. State the role of the cell membrane in the movement of substances. [1]

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Answer Key - Secondary 4 Pure Biology Quiz (Cells Biomolecules)

Section A: Cell Structure and Organisation

1. Root hair cells. (1)
2. Modifying, sorting, and packaging proteins/lipids for secretion or delivery to organelles. (1)
3. Mitochondria. (1)
4. Cell wall; Chloroplasts (or Large central vacuole). (2)
5. Provides more space for haemoglobin to bind and carry more oxygen. (2)
6. Muscle cells require more energy (ATP) for contraction; mitochondria are the site of aerobic respiration to produce this energy. (2)
7. Ribosomes. (1)
8. Provides structural support/strength; prevents the cell from bursting when turgid. (2)
9. Nucleus. (1)
10. Stores cell sap (water, sugars, salts); maintains turgidity to support the plant. (2)

Section B: Movement of Substances

11. The net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient. (2)
12. Diffusion refers to any soluble particle; osmosis refers specifically to the net movement of water molecules across a partially permeable membrane. (2)
13. (a) Out of the cell. (1) (b) Crenation / Shrunken. (1)
14. High glucose concentration lowers the water potential of the blood $\rightarrow$ water moves out of the red blood cells by osmosis (down water potential gradient) $\rightarrow$ cells shrink/crenate and may be damaged. (3)
15. The movement of particles from a region of lower concentration to a region of higher concentration (against the gradient) using energy from respiration. (2)
16. Mineral ion concentration in soil is often lower than inside the root hair cell $\rightarrow$ ions cannot move by diffusion $\rightarrow$ active transport is needed to move ions against the concentration gradient. (3)
17. Active transport is used $\rightarrow$ glucose is moved from the lumen (low concentration) into the villi (high concentration) $\rightarrow$ requires energy from ATP. (3)
18. Water enters the cell by osmosis $\rightarrow$ cell becomes turgid $\rightarrow$ the rigid cell wall exerts pressure (turgor pressure) to prevent the cell from bursting. (3)
19. Salting or sugaring of food (to kill bacteria via osmosis). (1)
20. Acts as a partially permeable membrane, controlling which substances enter or leave the cell. (1)