Cell – Structure and Functions – Short Answer Type Questions
CBSE Class 8 Science — Chapter 8: Cell — Structure and Functions
50 Short Answer Questions — Topic-wise • NCERT-aligned • Board-exam standard
Class: 8
Subject: Science
Chapter: Cell — Structure & Functions
CBSE Board Examinations (Study order):
- Read NCERT chapter and focus on organelle functions and labelled diagrams.
- Memorise key differences between plant and animal cells and practise sketches.
- Revise cell processes—photosynthesis, respiration and diffusion—for short answers.
Topic 1 — Fundamentals & Cell Theory (Q1–Q6)
- Q1. Define a cell in simple words.A cell is the smallest structural and functional unit of life.
- Q2. Name one unicellular organism and one multicellular organism.Unicellular: Amoeba. Multicellular: Human.
- Q3. What invention enabled the discovery of cells?The microscope.
- Q4. State one point of the cell theory.All living organisms are composed of one or more cells.
- Q5. Differentiate briefly between eukaryotic and prokaryotic cells.Eukaryotic cells have a true nucleus and membrane-bound organelles; prokaryotic cells lack these (e.g., bacteria).
- Q6. What is cytoplasm?The jelly-like fluid inside a cell where organelles are suspended.
Topic 2 — Cell Membrane & Transport (Q7–Q13)
- Q7. What is the cell membrane made of?Mainly lipids (phospholipids) and proteins.
- Q8. Explain 'selective permeability' of the cell membrane.It allows some substances to pass through while blocking others.
- Q9. What is diffusion?Movement of molecules from higher to lower concentration until evenly spread.
- Q10. Give one example of diffusion in the body.Oxygen moving from blood into tissues.
- Q11. Name a substance that passes through membrane by diffusion.Carbon dioxide or oxygen.
- Q12. What role does water play in cells?Solvent for biochemical reactions and helps maintain cell turgor and shape.
- Q13. Define osmosis (one line).Diffusion of water across a selectively permeable membrane from low solute to high solute concentration.
Topic 3 — Cell Wall & Plant Cell Features (Q14–18)
- Q14. Which cells have a cell wall?Plant cells, some fungi and many bacteria have cell walls.
- Q15. What is plant cell wall mainly made of?Cellulose.
- Q16. State one function of the cell wall.Provides strength, protection and shape to plant cells.
- Q17. Why do plant cells have large vacuoles?To store water and maintain turgor pressure for structural support.
- Q18. Name an organelle unique to plant cells involved in photosynthesis.Chloroplast.
Topic 4 — Nucleus & Genetic Material (Q19–23)
- Q19. What does the nucleus contain?Genetic material (DNA) and nucleolus.
- Q20. What is DNA?Deoxyribonucleic acid; the molecule that carries genetic information.
- Q21. State one function of the nucleus.Controls cell activities and stores hereditary information.
- Q22. Where are chromosomes found?In the nucleus of eukaryotic cells.
- Q23. What is the nucleolus?A dense region in the nucleus where ribosomal RNA is produced.
Topic 5 — Mitochondria & Respiration (Q24–28)
- Q24. What are mitochondria called and why?'Powerhouse of the cell' because they produce energy (ATP) by respiration.
- Q25. Where does cellular respiration occur?In mitochondria.
- Q26. Name one by-product of respiration.Carbon dioxide.
- Q27. Do plant cells perform respiration?Yes, all living cells perform respiration.
- Q28. Why do muscle cells have many mitochondria?They need more energy for contraction, so more mitochondria supply ATP.
Topic 6 — Chloroplasts & Photosynthesis (Q29–33)
- Q29. What is photosynthesis (brief)?Process where plants make food (glucose) using light, CO₂ and water, releasing oxygen.
- Q30. What pigment captures light in chloroplasts?Chlorophyll.
- Q31. Where in a plant cell are chloroplasts mainly found?In leaf mesophyll cells.
- Q32. Give one product of photosynthesis.Glucose (and oxygen).
- Q33. Why are chloroplasts green?Because chlorophyll pigment reflects green light.
Topic 7 — Ribosomes, ER & Golgi (Q34–38)
- Q34. What is the main function of ribosomes?They synthesise proteins.
- Q35. What does ER stand for and name two types?Endoplasmic reticulum; rough ER (with ribosomes) and smooth ER (without ribosomes).
- Q36. What is the role of the Golgi apparatus?Modifies, packages and transports proteins and lipids.
- Q37. Where are proteins modified and packaged in a cell?In the Golgi apparatus.
- Q38. Do both plant and animal cells have ribosomes?Yes, ribosomes are present in both.
Topic 8 — Vacuoles, Lysosomes & Cell Repair (Q39–43)
- Q39. What is a vacuole and its main role in plant cells?A storage sac; stores water, nutrients and helps maintain turgor pressure.
- Q40. What are lysosomes?Vesicles containing digestive enzymes to break down waste and worn-out organelles.
- Q41. How does cell division help in repair?New cells are produced to replace damaged or dead cells, enabling tissue repair.
- Q42. Name a simple type of cell division in unicellular organisms.Binary fission (e.g., in bacteria).
- Q43. What is regeneration (brief)?Ability of some organisms to regrow lost parts using cell division and differentiation.
Topic 9 — Specialised Cells & Functions (Q44–47)
- Q44. What feature helps root hair cells absorb more water?Large surface area due to long thin projections (root hairs).
- Q45. How are nerve cells adapted for rapid signal transmission?They have long axons and branched dendrites to carry impulses quickly.
- Q46. Why do red blood cells lack a nucleus?To provide more space for haemoglobin and increase oxygen-carrying capacity (in mammals).
- Q47. What is the role of guard cells?They open and close stomata to regulate gas exchange and water loss.
Topic 10 — Microscopy, Observations & Practical Tips (Q48–50)
- Q48. Which microscope is commonly used in school labs?Light microscope.
- Q49. Name a stain used to view onion epidermal cells.Iodine solution.
- Q50. Give one tip for a neat labelled diagram in exams.Draw clearly, label parts neatly and write magnification if required.
These short answer questions and answers follow the NCERT syllabus closely and are ideal for CBSE Class 8 board-exam standard revision and classroom practice.