Tissues – Short Answer Type Questions
Class 9 • Biology
Chapter 6: Tissues — 50 Short Answer Questions (NCERT-aligned)
Instructions: The following 50 short answer questions cover important concepts from Chapter 6 (Tissues). Each answer is concise yet explanatory, suitable for NCERT-level understanding and CBSE board exams.
Meristematic Tissue
1. Explain what meristematic tissue is and where it is located.
Meristematic tissue consists of actively dividing cells responsible for growth. It is found in apical regions (root and shoot tips), lateral regions (cambium), and intercalary regions (at internodes in grasses).
2. What characteristics distinguish meristematic cells from permanent cells?
Meristematic cells are small, thin-walled, densely cytoplasmic, with prominent nuclei and little or no vacuole; they divide frequently. Permanent cells are differentiated, often larger, with specialised structures and reduced division ability.
3. Describe the role of apical meristem in plant growth.
Apical meristem causes primary growth — elongation of roots and shoots — by continuous cell division at the tips, producing cells that differentiate into various tissues.
4. What is the function of lateral meristem (vascular cambium)?
Lateral meristem (vascular cambium) contributes to secondary growth — increasing the thickness/girth of stems and roots by producing secondary xylem and phloem.
5. Give an example of an intercalary meristem and its importance.
Intercalary meristems at the base of leaves or internodes in grasses enable rapid elongation and regrowth after grazing; they help restore length lost to damage.
Simple Permanent Tissues
6. Define parenchyma and state two functions.
Parenchyma is a simple tissue of living thin-walled cells; it functions in storage, photosynthesis (chlorenchyma), and secretion.
7. How does chlorenchyma differ from general parenchyma?
Chlorenchyma is parenchyma with chloroplasts specialised for photosynthesis; general parenchyma may lack chloroplasts and serve primarily in storage.
8. Describe collenchyma and its adaptive advantage.
Collenchyma consists of living cells with unevenly thickened primary walls (rich in pectin) providing flexible support to growing stems and leaves, allowing bending without breaking.
9. Explain sclerenchyma and its two main types.
Sclerenchyma has thick, lignified secondary walls and is usually dead at maturity. Its two forms are fibres (long, supporting) and sclereids (short, protective), both providing rigidity and protection.
10. Why are sclerenchyma cells often dead at maturity?
They develop thick lignified walls that make them impermeable and rigid; this specialization for support and protection often leaves them non-living when mature.
Complex Permanent Tissues — Xylem & Phloem
11. List the main components of xylem and their functions.
Xylem comprises tracheids and vessels (conduct water), xylem parenchyma (storage), and xylem fibres (support). Tracheids and vessels are dead, lignified conduits for upward water movement.
12. Describe how xylem vessels are adapted for transport.
Xylem vessels are long, hollow, tubular elements with lignified walls and perforated end walls, providing low-resistance pathways for continuous upward water flow driven by transpiration pull.
13. What are sieve tube elements and what role do they play?
Sieve tube elements are elongated living cells in phloem with sieve plates; they transport organic solutes (sugars) throughout the plant (source to sink) and rely on companion cells for metabolic support.
14. Explain the source-sink concept in phloem transport.
Source cells (eg. mature leaves) produce sugars transported via phloem to sink tissues (growing roots, fruits) where sugars are consumed or stored; flow direction depends on source-sink relationships.
15. How does phloem differ structurally from xylem?
Phloem consists of living sieve tube elements and companion cells, with thinner walls; xylem conducting elements are dead, lignified and primarily transport water.
16. Why are companion cells necessary for sieve tube elements?
Sieve tube elements lack nuclei and some organelles; companion cells provide metabolic and regulatory support required for phloem loading and functioning.
17. What is the role of xylem parenchyma?
Xylem parenchyma stores food and helps lateral transport of water and minerals within the xylem tissue.
18. State two functions of phloem fibres.
Phloem fibres provide mechanical strength and protection to phloem tissue and assist in plant support.
Animal Tissues — Epithelial
19. Define epithelial tissue and list two of its general functions.
Epithelial tissue forms sheets covering body surfaces and lining cavities; functions include protection, absorption, secretion, and sensation.
20. Differentiate between simple and stratified epithelium with examples.
Simple epithelium is a single cell layer (e.g., simple squamous in lung alveoli for diffusion). Stratified epithelium has multiple layers (e.g., stratified squamous in skin for protection).
21. Explain the structure and function of simple cuboidal epithelium.
Simple cuboidal epithelium has cube-shaped cells lining kidney tubules and gland ducts; it aids in secretion and absorption.
22. What adaptations help absorptive epithelium increase efficiency?
Microvilli (brush border) increase surface area; tight junctions and a thin cytoplasm aid selective absorption (e.g., intestinal lining).
23. Where are goblet cells found and what is their function?
Goblet cells are found in respiratory and intestinal linings and secrete mucus to trap particles and protect/ lubricate epithelial surfaces.
Animal Tissues — Connective
24. What is the extracellular matrix and why is it important in connective tissues?
The extracellular matrix (ECM) consists of fibres (collagen, elastin) and ground substance; it provides mechanical support, mediates biochemical signalling, and determines tissue properties.
25. Explain the structure and function of adipose tissue.
Adipose tissue consists of adipocytes storing fat droplets; it insulates the body, cushions organs and serves as an energy reserve.
26. How does cartilage differ from bone?
Cartilage has a flexible matrix with chondrocytes in lacunae and is avascular; bone has a mineralised matrix (calcium phosphate), osteocytes in lacunae and is vascular providing rigid support.
27. Describe the components and functions of blood as a connective tissue.
Blood has plasma (fluid matrix) and formed elements (RBCs, WBCs, platelets). It transports gases, nutrients, hormones and defends against infections while maintaining homeostasis.
28. What are tendons and ligaments composed of and what are their roles?
Tendons and ligaments are fibrous connective tissues rich in collagen fibres; tendons attach muscle to bone, ligaments connect bone to bone providing joint stability.
Animal Tissues — Muscular
29. Outline the main differences between skeletal, cardiac and smooth muscles.
Skeletal muscle: voluntary, multinucleate, striated, attached to bones. Cardiac: involuntary, striated, branched, intercalated discs, found in heart. Smooth: involuntary, non-striated, spindle-shaped cells in walls of hollow organs.
30. Why are skeletal muscle fibres multinucleate?
They form by fusion of myoblasts during development; multiple nuclei support high protein synthesis along long fibres for contraction.
31. Explain the role of intercalated discs in cardiac muscle.
Intercalated discs contain gap junctions and desmosomes that enable rapid electrical coupling and mechanical cohesion for coordinated heart contractions.
32. How does smooth muscle contraction differ from skeletal muscle contraction?
Smooth muscle contracts slowly and rhythmically, often under autonomic control, using actin-myosin interactions but lacking sarcomeric striations found in skeletal muscle.
Animal Tissues — Nervous
33. Describe the basic structure of a neuron.
A neuron has a cell body (soma) containing nucleus, dendrites that receive signals, and an axon which transmits impulses away from the cell body; axons may be myelinated for faster conduction.
34. What roles do neuroglia perform?
Neuroglia (glial cells) support neurons structurally and metabolically, form myelin, maintain ionic balance and participate in immune defence within the nervous system.
35. Explain how myelination affects nerve impulse conduction.
Myelin sheath (formed by glial cells) insulates axons and allows saltatory conduction, where impulses jump between nodes of Ranvier, increasing conduction velocity.
36. What is the synaptic cleft and its importance?
The synaptic cleft is the small gap between presynaptic and postsynaptic cells at a synapse; neurotransmitters cross this gap to transmit signals chemically between cells.
Practical, Diagrams & Comparison
37. What features help distinguish xylem and phloem in a stained slide?
Xylem vessels appear as large, thick-walled, hollow tubes often stained differently; phloem shows sieve tubes and companion cells with thinner walls and sieve plates.
38. Which stains are commonly used to study plant tissues and why?
Safranin (stains lignified walls red) and Fast Green or Alcian Blue are used to contrast tissues; iodine stains starch in parenchyma.
39. Give two tips for drawing diagrams of tissues in exams.
Draw clear, labelled, proportionate structures with titles; include 2–3 characteristic labels and write brief function points beside the diagram.
40. How would you identify parenchyma under microscope?
Look for isodiametric or polyhedral thin-walled living cells with large vacuoles and intercellular spaces; often many cells with similar appearance.
Higher-order Questions & Applications
41. Why is lignin important in sclerenchyma and xylem?
Lignin strengthens and waterproofs cell walls, providing mechanical support and preventing collapse of conducting vessels under tension during water transport.
42. Explain how tissue damage in plants is repaired.
Cells near wound areas activate meristematic activity (cambial or parenchymatous cells) to proliferate and differentiate, forming callus tissue that helps close the wound.
43. How does the structure of root hair cells relate to their function?
Root hair cells have long extensions (root hairs) increasing surface area for absorption of water and minerals and have many mitochondria for active uptake.
44. Why are neurons specialised for rapid communication?
Neurons have long extensions (axons) for distance transmission, synapses for targeted signalling, and myelin for fast conduction enabling quick responses and coordination.
45. Discuss how plant tissues contribute to mechanical strength of stems.
Sclerenchyma fibres, lignified xylem vessels, and collenchyma under epidermis together provide tensile strength, rigidity and flexible support enabling stems to bear leaves and resist wind.
Quick Revision & Exam Tips
46. Provide a one-line definition of tissue.
A tissue is a group of similar cells performing a common function.
47. What are the four basic animal tissues?
Epithelial, connective, muscular, and nervous tissues.
48. Suggest a fast revision strategy for this chapter before exams.
Make one-line definitions, two comparison tables (plant vs animal tissues, xylem vs phloem), and practise 4 labelled diagrams within 20–30 minutes daily.
49. Give two likely short-answer questions from NCERT/CBE exams on tissues.
(i) "Describe the structure and function of xylem." (ii) "Differentiate between parenchyma and sclerenchyma with examples."
50. State one tip to score marks in diagram-based questions on tissues.
Label clearly, write the diagram title, and add 2–3 brief function points or features near the diagram to gain complete marks.
All questions and answers are aligned with NCERT Class 9 Biology — Chapter 6: Tissues. Use these short Q&A for practice, revision, and board exam preparation.