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Cell structure and function
8 MDCAT Biology questions with answers and explanations.
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Which organelle is the main site of ATP production in eukaryotic cells?
- 1 Golgi apparatus
- 2 Mitochondrion
- 3 Lysosome
- 4 Ribosome
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Correct answer: Mitochondrion
Aerobic respiration, including the Krebs cycle and the electron transport chain, takes place in the mitochondria, which is why they are called the powerhouse of the cell.
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Ribosomes are made of:
- 1 DNA and protein
- 2 Lipids and protein
- 3 rRNA and protein
- 4 mRNA and carbohydrate
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Correct answer: rRNA and protein
A ribosome is built from ribosomal RNA (rRNA) and proteins. It reads mRNA and builds proteins.
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Which structure is found in plant cells but not in animal cells?
- 1 Cell wall
- 2 Mitochondria
- 3 Plasma membrane
- 4 Ribosomes
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Correct answer: Cell wall
Plant cells have a cellulose cell wall outside the plasma membrane. Animal cells have no cell wall.
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The rough endoplasmic reticulum looks rough because of:
- 1 Attached lysosomes
- 2 Lipid droplets
- 3 Attached ribosomes
- 4 Folded cell wall
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Correct answer: Attached ribosomes
Ribosomes attached to its outer surface give the rough ER its studded look. They make proteins that enter the ER.
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Which organelle contains hydrolytic enzymes for intracellular digestion?
- 1 Peroxisome
- 2 Lysosome
- 3 Nucleolus
- 4 Chloroplast
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Correct answer: Lysosome
Lysosomes hold acid hydrolases that break down worn-out organelles, food particles and invading microbes.
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Which of these is absent in prokaryotic cells?
- 1 Ribosomes
- 2 Plasma membrane
- 3 A membrane-bound nucleus
- 4 DNA
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Correct answer: A membrane-bound nucleus
Prokaryotes have their DNA in a nucleoid region with no nuclear envelope. They do have ribosomes, a plasma membrane and DNA.
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Which organelle modifies, sorts and packages proteins into vesicles?
- 1 Golgi apparatus
- 2 Smooth ER
- 3 Vacuole
- 4 Centriole
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Correct answer: Golgi apparatus
The Golgi apparatus receives proteins from the ER, modifies them (for example by adding sugar groups) and ships them in vesicles.
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Which cell structure helps form the spindle fibres during animal cell division?
- 1 Centrioles
- 2 Nucleolus
- 3 Golgi body
- 4 Chloroplast
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Correct answer: Centrioles
Centrioles, found in the centrosome of animal cells, organise the microtubules that form the spindle.