The Cell
11 Grade 10 General Science questions on The Cell, with worked marking schemes. 11 questions are available on this topic in full.
Question 1
4 marks(a) Name two structures found in both plant and animal cells that can be seen under an electron microscope but not under a light microscope. (2 marks)
(b) State two structural differences between a plant cell and an animal cell as seen under an electron microscope. (2 marks)
(4 marks)
Marking scheme
(a) Any two of the following, 1 mark each (2 marks): - Ribosomes - Rough endoplasmic reticulum - Smooth endoplasmic reticulum - Golgi apparatus - Nuclear pores/double nuclear membrane - Inner structure (cristae) of mitochondria (Accept endoplasmic reticulum once only.) (b) Any two correctly matched differences, 1 mark each (2 marks): - Plant cell has a cellulose cell wall; animal cell has none. - Plant cell has chloroplasts; animal cell has none. - Plant cell has a large central vacuole; animal cell has small, temporary vacuoles or none. - Animal cell has centrioles; plant cell (of flowering plants) lacks them. - Plant cell has plasmodesmata linking neighbouring cells; animal cell has none. - Plant cell stores starch grains; animal cell stores glycogen granules. - Plant cell has a regular/fixed shape; animal cell has an irregular shape.
Question 2
1 markIn a practical lesson, Akinyi drew a cheek cell that was 45 mm long in her drawing. The actual length of the cell was 0.06 mm. What is the magnification of her drawing?
A. ×2.7
B. ×750
C. ×75
D. ×7500
(1 mark)
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4 marksDraw a table to show four differences between a light microscope and an electron microscope. (4 marks)
(4 marks)
Marking scheme
Any four correct, matched differences, 1 mark each (4 marks). A difference is credited only when both sides are correct: - Source of illumination: light (visible light) | beam of electrons. - Lenses: glass lenses | electromagnets (electromagnetic lenses). - Magnification: low, up to about ×1500 | very high, up to about ×500 000 or more. - Resolving power: low, about 0.2 µm | very high, below about 1 nm. - Specimens: living or dead specimens can be viewed | only dead specimens, because they are placed in a vacuum. - Image: can show natural colours/stains | black and white image (on a screen or photograph). - Specimen preparation: simple and quick | complex and time-consuming. - Cost and size: cheap, small and portable | very expensive, large and fixed in one place. - Power: does not need electricity (can use a mirror) | requires a high-voltage electricity supply.
Question 4
1 markA researcher wants to watch living Paramecium moving about in a drop of pond water collected from Lake Naivasha. Why would an electron microscope be unsuitable for this work?
A. The specimen must be kept in a vacuum
B. Its resolving power is lower than a hand lens
C. The specimen is lit by ordinary light
D. It cannot magnify objects beyond ×100
(1 mark)
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Create a free account to see itQuestion 5
1 markA sperm cell must swim a long distance to reach the egg. Which organelle would be found in large numbers in the middle piece of a sperm cell?
A. Golgi apparatus
B. Mitochondria
C. Lysosomes
D. Ribosomes
(1 mark)
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4 marks(a) Explain why the cell is described as the basic unit of life. (2 marks)
(b) A group of Grade 10 learners is making a model of an animal cell using locally available materials. Suggest a suitable material to represent each of the following:
(i) the nucleus (1 mark)
(ii) the cell membrane (1 mark)
(4 marks)
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5 marksConstruct a concept map showing the levels of cell organisation in the human body, starting from the simplest level and ending with the whole organism. Give one example from the human body at each level. (5 marks)
(5 marks)
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4 marksExplain the role of each of the following in a cell:
(a) cell membrane (2 marks)
(b) lysosome (2 marks)
(4 marks)
Marking scheme
(a) Cell membrane, any two of the following, 1 mark each (2 marks): - It is selectively/partially permeable and controls which substances enter and leave the cell. - It encloses the cell contents/cytoplasm, separating them from the surroundings. - It has receptors for recognising other cells and chemical messages (hormones). - It takes in materials by forming vesicles (endocytosis) and releases materials (exocytosis). (b) Lysosome, any two of the following, 1 mark each (2 marks): - It contains digestive (hydrolytic) enzymes. - It breaks down worn-out organelles and old or damaged cells (autolysis). - It digests food particles or bacteria taken into the cell, e.g. in white blood cells. - Its membrane keeps the enzymes separate so that they do not digest the rest of the cell.
Question 9
1 markDuring a field trip to Kakamega Forest, learners studied a flowering plant. Which of the following plant structures is an organ?
A. Guard cell
B. Leaf
C. Xylem
D. Chloroplast
(1 mark)
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1 markA learner viewed onion epidermis cells and human cheek cells under a light microscope. Which structure did she see in the onion cells but NOT in the cheek cells?
A. Cell membrane
B. Cell wall
C. Cytoplasm
D. Nucleus
(1 mark)
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5 marksDraw and label a plant cell as seen under an electron microscope. (5 marks)
(5 marks)
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