Class IX SEBA Science – Chapter 6: Tissues
🌱 1. Are Plants and Animals Made of Same Types of Tissues?
- Tissues: Group of similar cells performing a specific function.
- Plants and animals have different types of tissues due to difference in lifestyle:
- Plants → Stationary, need mechanical support.
- Animals → Active, need coordination and movement.
🌿 2. Plant Tissues
🔹 Permanent Tissues (Cells have lost ability to divide)
a) Simple Permanent Tissues
- Parenchyma: Living, loosely packed, store food, help in photosynthesis (if chloroplast present = chlorenchyma).
- Collenchyma: Living, elongated, provides flexibility.
- Sclerenchyma: Dead, thick walls, provide strength.
b) Complex Permanent Tissues
- Made of more than one type of cell.
- Xylem: Transports water (tracheids, vessels, xylem parenchyma, xylem fibres).
- Phloem: Transports food (sieve tubes, companion cells, phloem parenchyma, phloem fibres).
🔹 Meristematic Tissues (Actively dividing cells)
- Apical meristem: Growth at tips of roots and shoots.
- Lateral meristem: Increases girth (e.g., cambium).
- Intercalary meristem: Found at base of leaves or internodes.
🐾 3. Animal Tissues
🔹 Epithelial Tissue (Protective covering)
- Squamous: Flat (e.g., lining of lungs).
- Cuboidal: Cube-shaped (e.g., kidney tubules).
- Columnar: Tall cells (e.g., intestine).
- Ciliated: Have cilia (e.g., respiratory tract).
🔹 Connective Tissue (Support and transport)
- Areolar: Between skin and muscles.
- Adipose: Stores fat.
- Ligaments: Connect bone to bone.
- Tendons: Connect muscle to bone.
- Cartilage: Smooth surface at joints.
- Bone: Hard, supports body.
- Blood: Transports gases, nutrients, hormones.
🔹 Muscular Tissue (Movement)
- Striated muscles: Voluntary, multi-nucleated (e.g., skeletal muscles).
- Unstriated muscles: Involuntary, spindle-shaped (e.g., intestine).
- Cardiac muscles: Involuntary, striated, branched (e.g., heart).
🔹 Nervous Tissue
- Made of neurons (nerve cells).
- Transmit messages between brain, spinal cord, and rest of body.
- Each neuron has a cell body, axon, and dendrites.
📘 Exercise Questions and Answers
1. Define a tissue.
Tissue is a group of similar cells that perform a specific function.
2. How are tissues classified in plants?
- Meristematic tissues: Divide and help in growth.
- Permanent tissues: Lost ability to divide; may be simple or complex.
3. What is the role of epidermis in plants?
- Protects plant from injury and water loss.
- Outer covering; sometimes has waxy coating (cutin).
4. How does cork protect plant?
- Made of dead cells with suberin.
- Prevents water loss and provides protection.
5. Complete the table:
| Tissue | Function | Location |
|---|---|---|
| Parenchyma | Storage, photosynthesis | Soft parts of plant |
| Collenchyma | Flexibility, support | Petiole, stem |
| Sclerenchyma | Strength | Hard seed coat, stem |
| Xylem | Transport water | All plant parts |
| Phloem | Transport food | All plant parts |
✍️ Extra Important Questions with Answers
1. What are the functions of xylem and phloem?
- Xylem: Transports water and minerals.
- Phloem: Transports food.
2. What is the difference between striated and unstriated muscles?
- Striated: Voluntary, striped, found in limbs.
- Unstriated: Involuntary, smooth, found in internal organs.
3. What are ligaments and tendons?
- Ligaments: Connect bones to bones.
- Tendons: Connect muscles to bones.
4. Why is blood considered a connective tissue?
Because it connects different parts of the body by transporting nutrients, oxygen, and waste.
5. Write differences between plant and animal tissues.
- Plant tissues have more dead cells for support.
- Animal tissues have more living cells for movement and coordination.
- Plant growth is localized; animal growth is uniform.
continue to Chapter 7: Diversity in Living Organisms?
