Grade 10 biology – Cell Structure and Specialisation Quiz
1. What is the main function of the mitochondrion in a cell?
Mitochondria are the sites of aerobic respiration where glucose is converted to ATP, the cell's main energy currency.
2. Which organelle contains chlorophyll and is the site of photosynthesis in plant cells?
Chloroplasts have chlorophyll and the structures needed for photosynthesis to make glucose from light, CO2 and water.
3. What is the primary chemical component of the plant cell wall?
Plant cell walls are mainly made of cellulose, a carbohydrate polymer that gives rigidity and support.
4. Which cell structure is the main site of protein synthesis?
Ribosomes read mRNA and assemble amino acids into proteins; they may be free in the cytoplasm or on the rough ER.
5. What is the main role of the large permanent vacuole in mature plant cells?
The vacuole stores water, ions and waste; when full it presses the cytoplasm against the cell wall giving turgor pressure.
6. Which feature best distinguishes eukaryotic cells from prokaryotic cells?
Eukaryotic cells have a true nucleus enclosed by a membrane; prokaryotes have no membrane-bound nucleus.
7. What is the primary function of the cell (plasma) membrane?
The plasma membrane is selectively permeable, regulating exchange of ions, nutrients and wastes between cell and environment.
8. What are plasmodesmata in plant tissues?
Plasmodesmata are microscopic channels through cell walls allowing communication and transport of substances between plant cells.
9. How is a root hair cell adapted to its role in the plant?
Root hair cells form long projections that increase surface area, improving absorption of water and minerals from the soil.
10. Which statement correctly describes xylem vessels?
Mature xylem vessels are dead, hollow tubes with lignin-strengthened walls that conduct water and dissolved minerals from roots to shoots.
11. What is a key feature of phloem sieve tubes in plants?
Phloem sieve tube elements transport sucrose and other solutes; companion cells maintain their metabolic functions.
12. What is the role of guard cells in a leaf?
Guard cells change shape by taking up or losing water, opening or closing stomata to control CO2 uptake and limit water loss.
13. Which adaptation helps red blood cells carry more oxygen?
Red blood cells are biconcave and anucleate to maximise surface area and space for haemoglobin, improving oxygen transport.
14. Which features adapt a sperm cell for fertilisation?
Sperm have a flagellum for motility and many mitochondria in the midpiece to supply ATP needed for swimming to the egg.
15. How is a typical nerve (neurone) cell specialised for its function?
Neurones are elongated with dendrites and an axon to carry electrical impulses quickly between different parts of the body.
16. Why do skeletal muscle cells contain many mitochondria?
Muscle contraction requires energy; many mitochondria produce ATP to meet the high energy demand during activity.
17. Which organelle is mainly involved in modifying, sorting and packaging proteins for secretion?
The Golgi apparatus receives proteins from the ER, modifies them (e.g. adds sugars), sorts and packages them into vesicles for secretion or use.
18. What distinguishes rough endoplasmic reticulum (RER) from smooth endoplasmic reticulum (SER)?
RER is studded with ribosomes for making proteins; SER is involved in lipid synthesis, detoxification and calcium storage.
19. What is the main function of lysosomes in animal cells?
Lysosomes contain hydrolytic enzymes that break down damaged organelles, pathogens and macromolecules for recycling.
20. Which process moves molecules from a region of higher concentration to a region of lower concentration without using cellular energy?
Diffusion is the passive movement of molecules down their concentration gradient and does not require ATP.
21. Which statement best describes osmosis?
Osmosis is a special case of diffusion for water: it moves from higher water potential (dilute) to lower water potential (concentrated) through a partially permeable membrane.
22. Which statement is a correct part of the cell theory?
One central idea of cell theory is that the cell is the basic structural and functional unit of all living organisms.
23. In microscopy, what does 'resolution' refer to?
Resolution determines how much detail can be seen; higher resolution allows two close points to be seen as distinct.
24. How do most bacteria reproduce?
Bacteria reproduce asexually by binary fission: the DNA replicates and the cell splits into two genetically similar daughter cells.
25. Which type of cell in a plant lacks chloroplasts and is specialised for transporting water?
Xylem vessels are dead at maturity, lack chloroplasts, and are specialised to conduct water and dissolved minerals from roots upward.