Science and Technology Class 9 Important Questions Chapter 17 Maharashtra Board

Introduction to Biotechnology

Short Questions

1. What defines a tissue in living organisms?

• A tissue is a group of cells with the same origin, structure, and function working together.

2. What is the smallest functional unit of a multicellular organism?

• The cell is the smallest structural and functional unit of a multicellular organism.

3. How do unicellular organisms like amoeba perform all functions?

• All functions are carried out by organelles within the single cell of the organism.

4. What are simple tissues, and give an example?

• Simple tissues are made of one type of cell, like epithelial tissue in animals.

5. What characterizes complex tissues in plants?

• Complex tissues consist of multiple cell types, such as xylem in plants.

6. Why do plants have more dead cells in their tissues?

• Dead cells provide structural support, as plants are sedentary and don’t move.

7. Why do animals require tissues with living cells?

• Living cells support movement, energy needs, and uniform growth in animals.

8. What are the four primary types of animal tissues?

• Epithelial, connective, muscular, and nervous tissues.

9. What is the primary role of epithelial tissue in animals?

• It forms protective coverings, like skin, to shield the body from external damage.

10. Where is epithelial tissue commonly located in the body?

• It is found in the skin, mouth cavity, blood vessel linings, and alveoli walls.

11. How does connective tissue contribute to body function?

• It connects body parts, supports structure, and transports materials like nutrients.

12. Why is blood considered a connective tissue?

• Blood transports oxygen, nutrients, and waste, connecting different body parts.

13. What enables muscular tissue to facilitate movement?

• Contractile proteins in muscle fibers allow contraction and relaxation for movement.

14. What is an example of a muscular tissue type?

• Striated muscles, found in skeletal muscles, are an example.

15. How does nervous tissue respond to external stimuli?

• It conducts signals to respond to stimuli like touch, sound, or light.

16. What is the structure of a nerve cell?

• A nerve cell has a cell body, dendrites, and a long axon for signal transmission.

17. Where is meristematic tissue located in plants?

• It is found in growth areas like root tips, stem tips, and cambium.

18. What is the primary function of meristematic tissue?

• It promotes plant growth by producing new cells through division.

19. What happens to cells in permanent tissues?

• They lose the ability to divide and perform specific functions like support.

20. What is the role of the epidermis in plants?

• It forms a protective outer layer, preventing water loss with a waxy cuticle.

21. What is biotechnology, and what does it involve?

• Biotechnology involves genetic engineering and hybridization to improve organisms.

22. What is the process of tissue culture?

• It involves growing cells or tissues in a nutrient-rich, aseptic medium ex vivo.

23. What type of medium is used in tissue culture?

• A nutrient-rich medium made from agar, which can be liquid, solid, or gel-like.

24. Who demonstrated ex vivo cell growth in plants?

• Frederick Campion Steward showed cells can grow outside the organism.

25. What are genetically modified (GM) crops?

• GM crops have altered DNA to gain traits like pest resistance or higher yields.

26. Name a specific GM crop variety used in agriculture.

• Golden Rice is a GM crop with enhanced nutritional value.

27. What is the purpose of agritourism?

• Agritourism combines agriculture and tourism to attract visitors to farms.

28. What is sericulture, and what does it produce?

• Sericulture is the rearing of silkworms to produce silk for fabrics.

29. What is the significance of the cuticle in plant epidermis?

• The cuticle reduces water loss from the plant’s stems and leaves.

30. Why are cocoons boiled in sericulture?

• Boiling kills the pupa and loosens silk fibers for unwinding and processing.

Long Questions

1. How do tissues help multicellular organisms perform various functions?

• Tissues are groups of cells with specific structures and functions, working together to perform tasks like movement or transport. For example, muscle tissues enable movement, and conducting tissues in plants transport water and food.

2. Why are plant and animal tissues different in structure and function?

• Plants are sedentary, so they have supportive tissues with dead cells, and growth occurs only in specific areas. Animals need living tissues for movement and energy, with uniform growth throughout their bodies.

3. What is the role of epithelial tissue in animals?

• Epithelial tissue forms protective coverings, like skin or linings of organs, preventing damage and controlling what enters the body. Its closely packed cells create continuous layers separated by a fibrous membrane.

4. How does connective tissue function in the animal body?

• Connective tissue links different body parts, providing support and transporting materials like oxygen and nutrients. For example, blood, a connective tissue, circulates nutrients and waste throughout the body.

5. What makes muscular tissue capable of movement?

• Muscular tissue contains contractile proteins that allow muscle fibers to contract and relax. This enables movements like bending an arm or walking by coordinating muscle actions.

6. How does nervous tissue help animals respond to stimuli?

• Nervous tissue, made of nerve cells with dendrites and axons, conducts signals to respond to stimuli like touch or sound. It integrates with muscular tissue to enable quick reactions, like pulling a hand away from heat.

7. Why does plant growth occur only in specific areas?

• Plant growth is limited to areas with meristematic tissue, which contains actively dividing cells. These tissues, found in root and stem tips, enable growth in length and thickness.

8. What is the difference between meristematic and permanent tissues?

• Meristematic tissues have dividing cells that promote growth, found in specific plant parts. Permanent tissues, formed after differentiation, lose the ability to divide and perform specific functions like support or transport.

9. How does the epidermis protect plants?

• The epidermis, a single layer of flat, closely packed cells, covers the plant’s surface, preventing water loss. A waxy cuticle layer on stems and leaves further retains water in underlying tissues.

10. What is the significance of biotechnology in agriculture?

• Biotechnology improves crops by introducing traits like pest resistance or higher yields through genetic changes. For example, GM crops like Golden Rice enhance nutrition and reduce crop loss.

11. How does tissue culture benefit plant production?

• Tissue culture allows large-scale production of disease-free plantlets in a short time using minimal resources. It can grow rare plants or those without viable seeds, like orchids, efficiently.

12. Why are GM crops resistant to environmental stresses?

• GM crops are engineered with genes that help them withstand extreme temperatures, droughts, or pests. This reduces the need for harmful pesticides and ensures growth in adverse conditions.

13. How does tissue culture support floriculture and forestry?

• Tissue culture produces high-quality, disease-free plantlets for flowers, fruits, or trees in large numbers. It supports afforestation and reforestation by supplying seedlings for large-scale planting.

14. What is the role of agritourism in combining agriculture and business?

• Agritourism creates centers with fruit, medicinal, or ornamental plants, attracting visitors for relaxation and education. Selling plantlets, fruits, or vegetables at these centers generates profit.

15. How does sericulture contribute to agro-complementary occupations?

• Sericulture involves rearing silkworms to produce silk, providing income through silk fabric production. It uses mulberry plants for feeding larvae, integrating agriculture with silk industry.