Class 9th Science Tissues Important QAs

🔹 Very Short Answer (1 mark)

Q1. What is a tissue?
Ans. A group of similar cells performing a specific function.

Q2. Who coined the term “tissue”?
Ans. Bichat.

Q3. How many types of plant tissues are there?
Ans. Two – Meristematic and Permanent.

Q4. What are meristematic tissues?
Ans. Actively dividing cells in plants responsible for growth.

Q5. Name the types of meristematic tissues.
Ans. Apical, Intercalary, Lateral.

Q6. Give one function of xylem.
Ans. Transport of water and minerals in plants.

Q7. Give one function of phloem.
Ans. Transport of food in plants.

Q8. Name the dead element of xylem.
Ans. Tracheids and vessels.

Q9. What is collenchyma?
Ans. A simple permanent tissue that provides flexibility to plants.

Q10. What is sclerenchyma?
Ans. A simple permanent tissue with thick lignified walls providing strength.

🔹 Short Answer (2–3 marks)

Q11. Write two features of meristematic tissue.
Ans. Cells are actively dividing, thin-walled, dense cytoplasm, and large nuclei.

Q12. Differentiate between apical and intercalary meristem.
Ans.

• Apical: Present at root/shoot tips, increases length.
• Intercalary: At internodes, helps in elongation.

Q13. Write one function each of xylem and phloem.
Ans.

• Xylem: Transport of water and minerals.
• Phloem: Transport of food from leaves to other parts.

Q14. What are guard cells?
Ans. Specialized cells surrounding stomata, controlling opening/closing.

Q15. What is the role of cork (phellem)?
Ans. Protective tissue, prevents water loss, provides insulation.

Q16. What are stomata? State their function.
Ans. Small pores in epidermis controlling gas exchange and transpiration.

Q17. Name the four elements of phloem.
Ans. Sieve tubes, companion cells, phloem parenchyma, phloem fibres.

Q18. Why is xylem called a complex tissue?
Ans. Because it is made of different types of cells (tracheids, vessels, fibres, parenchyma) performing a common function.

Q19. What is the function of epidermis in plants?
Ans. Protection from mechanical injury, water loss, and infection.

Q20. Define differentiation.
Ans. The process by which meristematic cells become specialized into permanent tissues.

🔹 Long Answer (4–5 marks)

Q21. Explain the structure and function of parenchyma.
Ans.

• Structure: Living cells, thin walls, large vacuoles.
• Functions: Photosynthesis (if chloroplast present), storage, gas exchange.

Q22. Explain the structure and function of collenchyma.
Ans.

• Structure: Living cells with unevenly thickened walls.
• Function: Provides flexibility and mechanical support.

Q23. Explain the structure and function of sclerenchyma.
Ans.

• Structure: Dead cells, thick lignified walls.
• Function: Provides strength and rigidity.

Q24. Differentiate between simple permanent and complex permanent tissues.

Q25. Differentiate between xylem and phloem.

Q26. What are the functions of epidermis in plants?
Ans. Protects plant, reduces water loss (cuticle), helps gas exchange (stomata).

Q27. What is cork? Write its function.
Ans. Cork is a protective tissue with dead cells having suberin. It prevents water loss and protects against pathogens.

Q28. Explain the role of stomata.
Ans. Allow gas exchange (CO₂, O₂), regulate transpiration by opening/closing.

Q29. How are guard cells different from other epidermal cells?
Ans. Guard cells are bean-shaped, contain chloroplasts, regulate stomata. Other epidermal cells are flat, lack chloroplasts.

Q30. Explain why phloem is considered a living tissue.
Ans. Because it consists of living elements (sieve tubes, companion cells, parenchyma) that help in transport of food.

🔹 Case Study / Application-Based (5–6 marks)

Q31. Case Study – Tree Bending in Wind
When strong wind blows, trees bend but do not break.
(i) Which tissue helps in flexibility?
(ii) How does it work?
Ans.
(i) Collenchyma.
(ii) Unevenly thickened walls provide both strength and flexibility.

Q32. Case Study – Water Transport
A tall tree transports water from roots to leaves.
(i) Which tissue is responsible?
(ii) Which forces help?
Ans.
(i) Xylem.
(ii) Transpiration pull and root pressure.

Q33. Why are sclerenchyma cells dead at maturity?
Ans. Because they have thick lignified walls that cut off protoplasm.

Q34. Why does desert plant have thick cuticle?
Ans. To reduce water loss through transpiration.

Q35. Why are sieve tubes without nucleus? How do they survive?
Ans. Companion cells support sieve tubes by providing proteins and energy.

Q36. Case Study – Potato & Storage
Potato stores starch in its cells. Which type of tissue stores it?
Ans. Parenchyma (specifically leucoplasts in parenchyma).

Q37. Why do coconut husks have hard, woody fibres?
Ans. Because they contain sclerenchyma fibres.

Q38. How does cork protect the plant?
Ans. Prevents water loss, protects from mechanical injury and pathogens.

Q39. Why does phloem transport food in both directions?
Ans. Because food is needed both in storage organs (roots, fruits) and growing parts (shoot tips).

Q40. Why is epidermis single-layered in plants?
Ans. To allow maximum protection while not blocking gas exchange.

🔹 Extra Important (41–50)

Q41. Define lignin.
Ans. A complex chemical that makes cell walls thick and rigid.

Q42. What are tracheids?
Ans. Elongated dead cells of xylem that transport water and give support.

Q43. Name the living mechanical tissue.
Ans. Collenchyma.

Q44. Which tissue makes up the husk of coconut?
Ans. Sclerenchyma fibres.

Q45. Which tissue is known as “packing tissue”?
Ans. Parenchyma.

Q46. Why is epidermis often covered with cuticle?
Ans. To prevent water loss.

Q47. Which permanent tissue has thick walls due to cellulose, not lignin?
Ans. Collenchyma.

Q48. Which plant tissue makes wood hard?
Ans. Sclerenchyma (especially xylem fibres).

Q49. Why do guard cells have chloroplasts?
Ans. To produce energy (ATP) needed to open/close stomata.

Q50. Why are tissues in multicellular organisms important?
Ans. They allow division of labour, efficiency, and better survival.