Animal and Plant Cells

1. 1 State [1 mark]

   State the function of the nucleus.

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   Model answer

   It contains the genetic material (DNA) and controls the activities of the cell.

   Mark scheme

   • Contains DNA / controls the cell's activities — 1 mark
2. 2 State [2 marks]

   State two structures that are found in plant cells but not in animal cells.

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   Model answer

   Any two from: cell wall, chloroplasts, permanent vacuole.

   Mark scheme

   • Cell wall — 1 mark
   • Chloroplasts — 1 mark
   • Permanent vacuole — 1 mark (maximum 2 marks)
3. 3 Name [4 marks]

   Figure 1 shows a plant cell. Name the structures labelled A, B, C and D.

   

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   Model answer

   A is the nucleus. B is a chloroplast. C is the (permanent) vacuole. D is the cell wall.

   Mark scheme

   • A: nucleus — 1 mark
   • B: chloroplast — 1 mark
   • C: (permanent) vacuole — 1 mark
   • D: cell wall — 1 mark
4. 4 Explain [2 marks]

   Muscle cells contain many mitochondria. Explain why.

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   Model answer

   Mitochondria are where aerobic respiration takes place, which releases energy. Muscle cells contract, and contraction needs a lot of energy.

   Mark scheme

   • Mitochondria release energy in (aerobic) respiration — 1 mark
   • Muscle cells need a lot of energy to contract — 1 mark
5. 5 Explain [3 marks]

   Palisade cells in a leaf contain many chloroplasts. Explain why.

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   Model answer

   Chloroplasts contain chlorophyll, which absorbs light. Light is needed for photosynthesis. Palisade cells carry out most of the leaf's photosynthesis, so more chloroplasts means more light absorbed and more glucose made.

   Mark scheme

   • Chloroplasts contain chlorophyll that absorbs light — 1 mark
   • Light is needed for photosynthesis — 1 mark
   • More chloroplasts means more photosynthesis / more glucose made — 1 mark
6. 6 Describe [4 marks]

   Describe the functions of the cell membrane, the cytoplasm, the cell wall and the ribosomes.

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   Model answer

   The cell membrane controls what passes into and out of the cell. Most chemical reactions take place in the cytoplasm. The cell wall (in plants) strengthens the cell and supports the plant. Ribosomes are where proteins are made.

   Mark scheme

   • Cell membrane controls what enters and leaves — 1 mark
   • Cytoplasm is where chemical reactions happen — 1 mark
   • Cell wall strengthens / supports — 1 mark
   • Ribosomes make proteins — 1 mark
7. 7 Compare [6 marks]

   Compare the structure of an animal cell with the structure of a plant cell.

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   Model answer

   Both cells have a nucleus, cytoplasm, a cell membrane, mitochondria and ribosomes. A plant cell also has a cellulose cell wall, which gives it a fixed shape, but an animal cell has no cell wall. A plant cell often has chloroplasts, which absorb light for photosynthesis, but an animal cell has none. A plant cell has a large permanent vacuole filled with cell sap, whereas an animal cell does not.

   Mark scheme

   • Both have a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes — 1 mark
   • Plant cells have a cell wall; animal cells do not — 1 mark
   • The plant cell wall is made of cellulose — 1 mark
   • Plant cells have chloroplasts; animal cells do not — 1 mark
   • Plant cells have a permanent vacuole; animal cells do not — 1 mark
   • Links a structure to its function (for example chloroplasts absorb light for photosynthesis) — 1 mark

Quick check

1. 1

   Which structure is the site of aerobic respiration?

   1. ANucleus
   2. BMitochondrion
   3. CRibosome
   4. DChloroplast
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   B: Mitochondrion

   Aerobic respiration takes place in the mitochondria, where energy is released from glucose.

2. 2

   Which structure makes proteins?

   1. AMitochondrion
   2. BCell membrane
   3. CRibosome
   4. DPermanent vacuole
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   C: Ribosome

   Ribosomes join amino acids together to make proteins.

3. 3

   Which of these is found in a plant cell but not in an animal cell?

   1. AMitochondria
   2. BNucleus
   3. CCell membrane
   4. DChloroplast
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   D: Chloroplast

   Chloroplasts are found only in plant cells (and some other organisms). Animal cells have a nucleus, mitochondria and a cell membrane.

4. 4

   What is the cell wall of a plant cell made from?

   1. ACellulose
   2. BProtein
   3. CChlorophyll
   4. DCell sap
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   A: Cellulose

   Plant cell walls are made of cellulose, which is strong and rigid.

5. 5

   Why do root cells not have chloroplasts?

   1. ARoots do not need energy
   2. BRoots are made of animal cells
   3. CThere is no light underground for photosynthesis
   4. DChloroplasts only work in the dark
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   C: There is no light underground for photosynthesis

   Chloroplasts absorb light for photosynthesis, and there is no light underground.

6. 6

   What is the permanent vacuole filled with?

   1. AChlorophyll
   2. BCell sap
   3. CCytoplasm
   4. DCellulose
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   B: Cell sap

   The permanent vacuole contains cell sap, a solution of sugars and salts.

7. 7

   A cell needs to release a great deal of energy. Which structure would you expect it to contain a lot of?

   1. AMitochondria
   2. BChloroplasts
   3. CPermanent vacuoles
   4. DCell walls
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   A: Mitochondria

   Mitochondria release energy in aerobic respiration, so cells with a high energy demand have many of them.

8. 8

   Which statement about mitochondria is correct?

   1. AThey make energy from nothing
   2. BThey are found only in plant cells
   3. CThey absorb light
   4. DThey release energy by aerobic respiration
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   D: They release energy by aerobic respiration

   Mitochondria release energy from glucose in respiration. Energy cannot be made or destroyed, only transferred.