Tissues ICSE Class 9: Plant and Animal Tissues, Location, Structure and Functions

What Tissues is about

Weightage: CISCE publishes no chapter weightage for ICSE Biology. Tissues is topic 1, Basic Biology (ii), of the Class IX part of the 2028 syllabus; the Class IX paper (80 marks, 2 hours) is set and marked by the school.Source: CISCE ICSE Biology (Science Paper 3) syllabus, examination year 2028 (Class IX)

Key concepts

Meristematic tissues in plants

Meristematic tissue is made of actively dividing cells that add new cells for growth.

Features: cells small, thin-walled (cellulose), with dense cytoplasm, a large nucleus, and no (or tiny) vacuoles; packed closely with no intercellular spaces.

Type	Location	Function
Apical	tips of root and shoot	increase in length (primary growth)
Intercalary	at the base of leaves or internodes (e.g. grasses, bamboo)	growth in length of internodes; regrowth of grazed grass
Lateral (cambium)	along the sides of stems and roots (vascular cambium, cork cambium)	increase in girth (secondary growth)

Worked example

Grass grows back after it is mowed, but a tree's main shoot does not regrow once its tip is cut. Explain.

Try it first, then show the solutionSolution

1. Grass has intercalary meristem at the bases of its leaves and internodes, below the cut.
2. In the tree, the apical meristem at the tip has been removed.

Answer: Intercalary meristem in grass survives mowing.

Simple permanent tissues: parenchyma, collenchyma, sclerenchyma

Permanent tissues form when meristem cells stop dividing and take up a fixed shape and job (differentiation).

Tissue	Structure	Location	Function
Parenchyma	living, thin-walled, round or oval, with intercellular spaces, large vacuole	cortex and pith of stems and roots, mesophyll of leaves, fleshy fruits	storage of food and water; photosynthesis when it has chloroplasts (chlorenchyma); buoyancy in aquatic plants when it has large air spaces (aerenchyma)
Collenchyma	living, elongated, walls thickened at the corners (cellulose and pectin), few spaces	below the epidermis of young stems, leaf stalks	mechanical support with flexibility; lets stems and leaves bend without breaking
Sclerenchyma	dead cells with very thick, lignified walls, no spaces; long fibres or short sclereids (stone cells)	stems, around vascular bundles, husk of coconut, seed coats, grit in pear	strength and rigidity; protection

The epidermis (outer layer, often with a waxy cuticle and stomata) and cork (dead cells with suberin, in older stems) are protective tissues.

Worked example

Why can a coconut husk and jute be made into ropes?

Try it first, then show the solutionSolution

1. Both contain long sclerenchyma fibres.
2. Their walls are thick and lignified, so they are strong.

Answer: They are rich in strong sclerenchyma fibres.

Complex permanent tissues: xylem and phloem

A complex tissue has more than one type of cell working together. Xylem and phloem form the vascular (conducting) tissue.

Xylem (conducts water and minerals upwards from roots to leaves; gives mechanical support):

• Tracheids: long, dead, lignified cells with tapering ends.
• Vessels: long tubes of dead cells joined end to end, with end walls lost.
• Xylem parenchyma: living; stores food.
• Xylem fibres: dead sclerenchyma; support.

Phloem (conducts food (sugar) from leaves to other parts: translocation, in both directions):

• Sieve tubes: living tubes with perforated end walls (sieve plates); no nucleus in mature cells.
• Companion cells: living, with a nucleus; control the sieve tubes.
• Phloem parenchyma: stores food.
• Phloem fibres: the only dead part; support.

Role in physiological processes: xylem carries water for photosynthesis and replaces water lost in transpiration; phloem carries the sugars made in photosynthesis to growing parts and storage organs.

Worked example

A ring of bark (including phloem) is removed from a tree trunk. After some weeks the bark just above the ring swells. Explain.

Try it first, then show the solutionSolution

1. Removing the bark removes the phloem at that level.
2. Food coming down from the leaves cannot pass the ring and collects above it.
3. Xylem (deeper, in the wood) is intact, so water still reaches the leaves.

Answer: Food transport by phloem is blocked; food accumulates above the ring.

Epithelial tissue

Epithelial tissue covers the body and lines organs and cavities. Cells are closely packed with almost no intercellular spaces, resting on a basement membrane.

Type	Structure	Location	Function
Squamous	thin, flat cells like floor tiles	lining of lung alveoli, blood vessels, mouth; outer skin (in layers: stratified)	exchange of gases by diffusion; protection
Cuboidal	cube-shaped	kidney tubules, ducts of glands, thyroid	absorption, secretion
Columnar	tall, pillar-like cells, often with microvilli	lining of stomach and intestine	secretion of digestive juices; absorption of digested food
Ciliated	cuboidal or columnar cells with cilia	trachea (windpipe), oviducts	cilia beat to move mucus and dust out, or move the egg
Glandular	columnar cells that secrete	sweat glands, salivary glands, goblet cells	secretion (sweat, saliva, mucus)

Worked example

Why are the walls of lung alveoli made of squamous epithelium and not columnar epithelium?

Try it first, then show the solutionSolution

1. Gases must diffuse quickly between air and blood.
2. Squamous cells are very thin and flat, giving the shortest diffusion distance.
3. Tall columnar cells would slow diffusion.

Answer: Thin squamous cells allow fast exchange of gases.

Connective tissue

Connective tissue binds, supports and connects other tissues. Cells are loosely spaced in a large amount of matrix (which may be jelly-like, fibrous, firm, hard or fluid).

Type	Structure	Location	Function
Areolar	loose network of fibres and cells	under the skin, between organs, around blood vessels	fills spaces, binds skin to muscles, repairs tissues
Adipose	cells filled with fat droplets	under the skin, around kidneys and heart	stores fat; insulates; cushions organs
Tendon	dense, parallel white fibres; strong, little stretch	joins muscle to bone	transmits pull of muscle
Ligament	dense, elastic (yellow) fibres; strong and flexible	joins bone to bone at joints	holds joints together, allows movement
Cartilage	cells in a firm, flexible matrix	ends of bones, nose tip, ear pinna, rings of trachea	smooths joints, gives flexible support
Bone	hard matrix of calcium phosphate and protein; cells in rings	skeleton	support, protection, movement; makes blood cells (marrow)
Blood	fluid matrix (plasma) with red cells, white cells, platelets	heart and blood vessels	transport of oxygen, food, wastes, hormones; defence; clotting

Worked example

A footballer tears the tissue connecting his calf muscle to the heel bone. Name the tissue and its type.

Try it first, then show the solutionSolution

1. Muscle to bone is joined by a tendon.
2. A tendon is dense fibrous connective tissue.

Answer: Tendon (Achilles tendon), a connective tissue.

Muscular and nervous tissue

Muscular tissue: long cells (muscle fibres) that contract and relax to cause movement.

Type	Structure	Location	Control
Striated (skeletal)	long, cylindrical, unbranched, many nuclei, with striations (light and dark bands)	attached to bones (arms, legs)	voluntary; contracts fast, tires quickly
Unstriated (smooth)	spindle-shaped, one nucleus, no striations	walls of stomach, intestine, blood vessels, bladder, iris	involuntary; slow, sustained contraction
Cardiac	cylindrical, branched, one or two nuclei, striated, with intercalated discs	heart wall only	involuntary; rhythmic, never tires

Nervous tissue: made of neurons (nerve cells), which receive stimuli and carry electrical impulses quickly, plus supporting cells.

• A neuron has a cell body (cyton) with nucleus, short branched dendrites (bring impulses to the cell body) and one long axon (carries impulses away), often covered by a fatty myelin sheath.
• Found in the brain, spinal cord and nerves; it controls and coordinates body activities.

Worked example

Why does the heart need muscle that does not tire?

Try it first, then show the solutionSolution

1. The heart beats continuously throughout life.
2. Cardiac muscle contracts rhythmically and involuntarily without fatigue.

Answer: It must pump blood non-stop.

Tissues in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Animal Tissues: Epithelial, Connective, Muscular and Nervous
• Plant Tissues: Meristematic and Permanent

Tissues: key facts

Levels of organisation

$\text{cell}\to \text{tissue}\to \text{organ}\to \text{system}\to \text{organism}$

Increasing complexity.

Xylem

$\text{tracheids}+\text{vessels}+\text{xylem parenchyma}+\text{xylem fibres}$

Water up; only parenchyma living.

Phloem

$\text{sieve tubes}+\text{companion cells}+\text{phloem parenchyma}+\text{phloem fibres}$

Food both ways; only fibres dead.

Four animal tissues

$\text{epithelial}+\text{connective}+\text{muscular}+\text{nervous}$

Cover, connect, contract, conduct.

Tissues: diagrams to practise

Practise each one on paper: draw it from the checklist, then tick off every label.

How the school exam asks Tissues

The question patterns to expect, and the method that works for each.

Tricks to remember Tissues

Short memory aids. Say each one aloud once, then use it on a question the same day.

• Four Cs of animal tissues

  Epithelial Covers, Connective Connects, Muscular Contracts, Nervous Conducts.

  Use it when: Main types and functions.

• Tendon-Ligament: 'MTB and BLB'

  Muscle-Tendon-Bone; Bone-Ligament-Bone.

  Use it when: Tendon versus ligament.

• Collenchyma corners

  Collenchyma = Corners thickened; Sclerenchyma = Stiff and dead.

  Use it when: Simple permanent tissues.

• Xylem = water up; Phloem = food flow

  Xylem eXports water up; Phloem feeds.

  Use it when: Vascular tissues.

Tissues: exam-level solved questions

Ordered from exam level to HOTS. Cover the solution, write your own, then compare step by step.

Case-study practice (Section B style)

Read the situation, then answer every part. In a school exam set on the board pattern this is a 5-mark question split into 2 + 1 + 2 marks.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Where students lose marks in Tissues

The slips examiners see most often, and what to write instead.

• ✗Mistake: Tendon and ligament swapped

  The two are both dense connective tissue.

  Wrong working

  A ligament joins muscle to bone.

  Right working

  Tendon: muscle to bone; ligament: bone to bone.

  ✓Do this: MTB, BLB.

  Usually costs: 1 mark.

• ✗Mistake: Saying all xylem is dead

  Students forget xylem parenchyma.

  Wrong working

  Xylem is a dead tissue.

  Right working

  Tracheids, vessels and fibres are dead; xylem parenchyma is living.

  ✓Do this: Name the living component.

  Usually costs: 1 mark.

• ✗Mistake: Vague function

  'Gives support' is written for every tissue.

  Wrong working

  Collenchyma gives support.

  Right working

  Collenchyma gives mechanical support with flexibility to young stems and leaf stalks.

  ✓Do this: Add what is special: flexibility, rigidity, storage.

  Usually costs: 1/2-1 mark.

• ✗Mistake: Wrong control of muscles

  Cardiac muscle is striated, so students call it voluntary.

  Wrong working

  Cardiac muscle is voluntary because it is striated.

  Right working

  Cardiac muscle is striated but involuntary.

  ✓Do this: Only skeletal muscle is voluntary.

  Usually costs: 1 mark.

Practice questions on Tissues

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · MCQExam level

   Which tissue is responsible for growth in length of a root?
   (a) lateral meristem
   (b) apical meristem
   (c) intercalary meristem
   (d) cork

   Hint

   Tip.

   Answer

   (b)

2. Q2 · 1 mark · MCQExam level

   Cartilage is found in:
   (a) the heart wall
   (b) the tip of the nose
   (c) the lining of the stomach
   (d) the brain

   Hint

   Flexible support.

   Answer

   (b)

3. Q3 · 3 marks · Very short answerExam level

   Name the tissue: (a) stores fat under the skin, (b) makes up the husk of coconut, (c) lines blood vessels.

   Hint

   Adipose; sclerenchyma; squamous.

   Answer

   (a) Adipose tissue (b) Sclerenchyma (fibres) (c) Squamous epithelium

4. Q4 · 2 marks · Short answerExam level

   Give two differences between meristematic and permanent tissue.

   Hint

   Division, vacuoles.

   Answer

   Meristematic cells divide actively; permanent cells do not. Meristematic cells have dense cytoplasm and no large vacuole; permanent cells usually have large vacuoles (and may be dead).

5. Q5 · 2 marks · Short answerHarder exam level

   Why are the walls of the stomach and intestine lined by smooth muscle and not skeletal muscle?

   Hint

   Involuntary, slow.

   Answer

   Food must be moved along by slow, rhythmic, sustained contractions (peristalsis) that happen without our conscious control; smooth muscle is involuntary and does not tire like skeletal muscle.

6. Q6 · 2 marks · Short answerHarder exam level

   How is the structure of sclerenchyma suited to its function, and why are its cells dead?

   Hint

   Lignin.

   Answer

   Thick lignified walls with no spaces make it strong and rigid for support. Lignin is impermeable, so the protoplasm is cut off from water and food and dies; only the strong walls remain.

7. Q7 · 2 marks · Short answerHarder exam level

   Name the tissue that plays the main role in each process: (a) ascent of water in a tree, (b) absorption of digested food, (c) exchange of oxygen in the lungs, (d) carrying hormones in the body.

   Hint

   One tissue each.

   Answer

   (a) Xylem (b) Columnar epithelium (with microvilli) of the small intestine (c) Squamous epithelium of alveoli (d) Blood

8. Q8 · 3 marks · Short answerHarder exam level

   A young sunflower stem bends in the wind without breaking, but an old tree trunk is rigid. Explain using tissues.

   Hint

   Collenchyma versus secondary xylem.

   Answer

   The young stem's support comes from collenchyma (living, corners thickened, flexible) and turgid parenchyma. The trunk has much secondary xylem (wood) and sclerenchyma with thick lignified walls made by the cambium, which are rigid.

9. Q9 · 3 marks · Short answerHarder exam level

   Give the function of (a) companion cells, (b) cilia in the oviduct, (c) myelin sheath.

   Hint

   Control; movement; insulation.

   Answer

   (a) Control the working of sieve tubes. (b) Move the egg along the oviduct. (c) Insulates the axon and speeds up the impulse.

10. Q10 · 3 marks · Short answerHOTS / competency

    In a disease, the cartilage at the ends of the knee bones wears away. Predict two effects and explain, naming the tissues involved.

    Hint

    Friction, pain.

    Answer

    Bone rubs directly on bone, causing pain and swelling, and movement becomes stiff and restricted. Cartilage (connective tissue) normally provides a smooth, cushioning surface; bone is hard and cannot do this.

11. Q11 · 3 marks · Short answerHOTS / competency

    A plant in a waterlogged field and a plant in a desert are compared. Which tissue would you expect to be more developed in (a) the stem of the water plant, (b) the outer layer of the desert plant's leaves? Explain each.

    Hint

    Air spaces; cuticle.

    Answer

    (a) Aerenchyma: large air spaces store air for root respiration and give buoyancy. (b) A thick epidermis with a heavy waxy cuticle (and sunken stomata), which reduces water loss.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.Tissue for increase in girth?Show answer

   Lateral meristem (cambium).

2. 2.Parenchyma with chloroplasts is called?Show answer

   Chlorenchyma.

3. 3.Only dead part of phloem?Show answer

   Phloem fibres.

4. 4.Epithelium lining the trachea?Show answer

   Ciliated epithelium.

5. 5.Tissue joining muscle to bone?Show answer

   Tendon.

6. 6.Fluid connective tissue?Show answer

   Blood.

7. 7.Muscle with intercalated discs?Show answer

   Cardiac muscle.

8. 8.Part of a neuron that carries impulses away from the cell body?Show answer

   Axon.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Can you name three meristems with locations?
• ☐Can you compare parenchyma, collenchyma and sclerenchyma?
• ☐Can you list the four elements each of xylem and phloem?
• ☐Can you give the location of five epithelia?
• ☐Can you distinguish tendon, ligament, cartilage and bone?
• ☐Can you compare the three muscles and draw a neuron?

Tissues: frequently asked questions