Important Questions For All Chapters – Science Class 9
Short Questions
1. What is a tissue?
Answer: A tissue is a group of cells similar in structure and function that work together to perform a specific activity.
2. Name the types of plant tissues.
Answer: The two main types of plant tissues are meristematic tissue and permanent tissue.
3. What is the function of meristematic tissue?
Answer: Meristematic tissue helps in the growth of plants by continuously dividing.
4. Which tissue makes up the husk of coconut?
Answer: The husk of coconut is made up of sclerenchyma tissue.
5. Where is apical meristem found?
Answer: Apical meristem is found at the growing tips of stems and roots.
6. Name the two complex permanent tissues in plants.
Answer: The two complex permanent tissues are xylem and phloem.
7. Which tissue is responsible for movement in our body?
Answer: Muscular tissue is responsible for movement in our body.
8. What are the functions of stomata?
Answer: Stomata help in gaseous exchange and transpiration in plants.
9. Name the tissue that connects muscles to bones.
Answer: Tendon connects muscles to bones.
10. What is the function of cardiac muscles?
Answer: Cardiac muscles perform rhythmic contraction and relaxation to pump blood throughout life.
Long Questions
1. Differentiate between plant and animal tissues.
Answer:
- Plant tissues may have dead cells, while animal tissues are mostly made of living cells.
- Growth in plants is limited to specific regions (meristem), while animals show uniform growth.
- Plants have supportive tissues for upright structure; animals have tissues specialized for movement.
2. Explain the different types of meristematic tissue.
Answer:
- Apical Meristem: Found at root and shoot tips, responsible for increase in length.
- Lateral Meristem: Found along the sides of stems and roots, increases girth.
- Intercalary Meristem: Present near nodes; helps in elongation of internodes.
3. What is permanent tissue? How is it formed?
Answer: Permanent tissue is formed when meristematic cells take up specific roles, lose the ability to divide, and become specialized. This process is called differentiation.
4. Describe the structure and function of parenchyma, collenchyma, and sclerenchyma.
Answer:
- Parenchyma: Living cells with thin walls; store food and sometimes contain chlorophyll.
- Collenchyma: Living cells with thickened corners; provide flexibility and support.
- Sclerenchyma: Dead cells with thick lignified walls; provide strength and rigidity.
5. Explain the structure and function of xylem and phloem.
Answer:
- Xylem: Made up of tracheids, vessels, xylem fibres, and xylem parenchyma; transports water and minerals.
- Phloem: Composed of sieve tubes, companion cells, phloem fibres, and phloem parenchyma; transports food from leaves to other parts.
6. What is the role of epidermis in plants?
Answer: Epidermis protects the plant from water loss, mechanical injury, and fungal infection. In leaves, it has stomata for gaseous exchange and transpiration.
7. What is cork and how does it act as a protective tissue?
Answer: Cork is formed from secondary meristem. Its cells are dead, compactly arranged, and contain suberin, making them waterproof and protective against gases and water loss.
8. Describe the types of epithelial tissue in animals and their functions.
Answer:
- Squamous Epithelium: Thin and flat; forms delicate lining in lungs and blood vessels.
- Stratified Squamous: Many layers; found in skin and mouth for protection.
- Cuboidal Epithelium: Cube-shaped; found in kidney tubules, provides support.
- Columnar Epithelium: Tall cells; found in intestine for absorption.
- Ciliated Columnar: With cilia; in respiratory tract to move mucus.
- Glandular Epithelium: Secretes substances.
9. Explain the various connective tissues and their roles.
Answer:
- Blood: Transports gases, nutrients, and wastes.
- Bone: Provides framework and support.
- Ligaments: Connect bones to bones.
- Tendons: Connect muscles to bones.
- Cartilage: Provides flexibility at joints.
- Areolar Tissue: Fills spaces and supports organs.
- Adipose Tissue: Stores fat and acts as insulator.
10. Describe the structure of striated, unstriated, and cardiac muscles.
Answer:
- Striated: Long, cylindrical, multinucleated, voluntary; present in limbs.
- Unstriated (Smooth): Spindle-shaped, uninucleate, involuntary; found in stomach, blood vessels.
- Cardiac: Branched, cylindrical, uninucleate, involuntary; found in the heart.
11. What are neurons? Describe their structure and function.
Answer: Neurons are nerve cells forming nervous tissue. Each neuron has a cell body with nucleus, dendrites for receiving signals, and an axon for transmitting impulses. They help in coordination and response to stimuli.
12. Differentiate between simple and complex permanent tissues.
Answer:
- Simple Tissue: Made of one type of cell (parenchyma, collenchyma, sclerenchyma).
- Complex Tissue: Made of more than one type of cell (xylem and phloem).
13. What is the function of meristematic tissue in plants?
Answer: Meristematic tissue helps in plant growth. It divides continuously and forms new cells for increase in length, girth, and formation of organs.
14. Write the functions of the following: (a) Ligament (b) Tendon (c) Cartilage.
Answer:
(a) Ligament – Connects bones to bones and provides strength.
(b) Tendon – Connects muscles to bones and enables movement.
(c) Cartilage – Smoothens bone surfaces at joints and provides flexibility.
15. Explain the importance of division of labour in multicellular organisms.
Answer: In multicellular organisms, different groups of cells perform specific functions efficiently (e.g., nerve cells for messages, muscle cells for movement, xylem for water transport). This division of labour increases overall efficiency and survival.
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