20 Very Short Question Answers
Question 1. What is a tissue?
Answer: A tissue is a group of similar cells that work together to perform a specific function.
Question 2. Name two conducting tissues in plants.
Answer: The two conducting tissues in plants are xylem and phloem.
Question 3. Which tissue transports water and minerals in plants?
Answer: Xylem transports water and minerals in plants.
Question 4. Which tissue transports food in plants?
Answer: Phloem transports food in plants.
Question 5. What is the function of apical meristem?
Answer: Apical meristem helps in the growth of roots and shoots in length.
Question 6. Where is lateral meristem found?
Answer: Lateral meristem is found along the sides or circumference of stems.
Question 7. What is the function of intercalary meristem?
Answer: Intercalary meristem helps plants regrow after cutting or grazing.
Question 8. What is differentiation?
Answer: Differentiation is the process by which meristematic cells become specialised to perform specific functions.
Question 9. Name the outermost protective tissue of plants.
Answer: The outermost protective tissue of plants is epidermis.
Question 10. What is cuticle?
Answer: Cuticle is a waxy layer on the epidermis that reduces water loss.
Question 11. What are stomata?
Answer: Stomata are tiny pores present in the epidermis of leaves and young stems.
Question 12. Name three simple permanent tissues.
Answer: The three simple permanent tissues are parenchyma, collenchyma and sclerenchyma.
Question 13. Which tissue gives flexibility to young stems?
Answer: Collenchyma gives flexibility to young stems.
Question 14. Which tissue makes coconut husk hard?
Answer: Sclerenchyma makes coconut husk hard.
Question 15. Name the four main types of animal tissues.
Answer: The four main animal tissues are epithelial, connective, muscular and nervous tissues.
Question 16. What is the function of epithelial tissue?
Answer: Epithelial tissue protects body surfaces and lines internal organs.
Question 17. What does a tendon connect?
Answer: A tendon connects muscle to bone.
Question 18. What does a ligament connect?
Answer: A ligament connects bone to bone.
Question 19. What is a neuron?
Answer: A neuron is a nerve cell that receives and transmits messages.
Question 20. What is totipotency?
Answer: Totipotency is the ability of a single plant cell to develop into a complete plant.
C. 15 Short Question Answers
Question 1. Why are plant and animal tissues different?
Answer: Plant and animal tissues are different because plants and animals have different needs. Plants are mostly fixed in one place and need strong tissues for support. Their cells have cell walls, which give rigidity. Animals usually move from place to place, so their tissues are more flexible. Animal cells do not have cell walls. Plants have tissues like xylem and phloem for transport, while animals have tissues like muscular and nervous tissues for movement and coordination.
Question 2. Write the main features of meristematic tissue.
Answer: Meristematic tissue is made of actively dividing cells. These cells are small, have thin cell walls, dense cytoplasm, many organelles and a large prominent nucleus. Vacuoles are generally absent. The cells are tightly packed with little or no intercellular space. These features help the cells divide continuously.
Question 3. Differentiate between apical, lateral and intercalary meristems.
Answer: Apical meristem is present at root and shoot tips and helps in growth in length. Lateral meristem is present along the sides of the stem and helps increase girth. Intercalary meristem is present at the base of internodes or near nodes and helps in regrowth after cutting or grazing.
Question 4. What is epidermis? Write its functions.
Answer: Epidermis is the outermost protective layer of the plant body. It protects plants from mechanical injury, microorganisms, parasites and water loss. In roots, epidermal cells form root hairs for absorption of water and minerals. In leaves, epidermis has stomata for gaseous exchange and transpiration.
Question 5. Why is cuticle thick in desert plants?
Answer: Desert plants live in hot and dry conditions where water loss is a major problem. A thick cuticle reduces water loss through transpiration. It also protects the plant from mechanical injury and harsh environmental conditions. Therefore, a thick cuticle is useful for desert plants.
Question 6. Write the functions of parenchyma.
Answer: Parenchyma is a living simple permanent tissue with thin walls. Its main function is storage of food. In green parts of plants, it helps in photosynthesis. In aquatic plants, parenchyma may have large air spaces and helps the plant float.
Question 7. Why does collenchyma provide flexibility?
Answer: Collenchyma cells are living cells with unevenly thickened corners due to pectin deposition. This structure provides support as well as flexibility. Because of collenchyma, young stems and tendrils can bend without breaking.
Question 8. Why is sclerenchyma hard and strong?
Answer: Sclerenchyma cells have very thick walls due to lignin deposition. Most of these cells are dead. Their thick lignified walls make them hard, strong and rigid. Therefore, sclerenchyma provides strength to plant parts such as coconut husk, seed coats and nut shells.
Question 9. Differentiate between xylem and phloem.
Answer: Xylem transports water and minerals from roots to other parts of the plant. It is mostly made up of dead cells and also provides mechanical strength. Phloem transports food from leaves to other parts of the plant. It is mostly made up of living cells and includes sieve tubes and companion cells.
Question 10. What are the main functions of epithelial tissue?
Answer: Epithelial tissue forms the outer covering of the body and lines internal organs. It protects against injury and germs, helps in absorption, secretion, gaseous exchange and sensory functions. For example, epithelial tissue in lungs helps in gas exchange, while epithelial tissue in the intestine helps in absorption.
Question 11. Why is blood called connective tissue?
Answer: Blood is called connective tissue because it connects different parts of the body by transporting materials. It carries oxygen, nutrients, hormones and wastes. Its matrix is fluid plasma, and it contains RBCs, WBCs and platelets.
Question 12. Differentiate between tendon and ligament.
Answer: Tendon connects muscle to bone and helps in movement by transmitting force from muscles to bones. Ligament connects bone to bone and provides stability to joints. Ligaments also prevent excessive movement and dislocation.
Question 13. Write the differences between skeletal, smooth and cardiac muscles.
Answer: Skeletal muscles are voluntary, striated and attached to bones. They help in body movements like walking and writing. Smooth muscles are involuntary and non-striated. They are found in organs like the stomach and intestine. Cardiac muscles are involuntary, branched and faintly striated. They are found only in the heart and work continuously.
Question 14. Describe the structure of a neuron.
Answer: A neuron has three main parts: cell body, dendrites and axon. The cell body contains the nucleus and controls cell activities. Dendrites receive signals from other neurons. The axon is a long fibre that carries messages away from the cell body. Axon terminals pass the message to other cells.
Question 15. What is the musculoskeletal system?
Answer: The musculoskeletal system is made up of bones, muscles, joints, cartilage, tendons and ligaments. It helps in movement, support, posture and protection of delicate organs. Muscles pull bones to produce movement, and joints allow bones to move in specific directions.
D. 10 Long Question Answers
Question 1. Explain the different types of meristematic tissues in plants.
Answer:
Meristematic tissues are plant tissues made up of actively dividing cells. These tissues help plants grow throughout life. The cells of meristematic tissues have thin cell walls, dense cytoplasm, large nuclei and little or no vacuoles.
There are three main types of meristematic tissues:
1. Apical meristem:
Apical meristem is present at the tips of roots and shoots. It helps roots and shoots grow in length. For example, root tips grow longer because of apical meristem.
2. Lateral meristem:
Lateral meristem is present along the circumference or sides of stems. It increases the girth or thickness of stems. It is responsible for the formation of annual rings in woody plants.
3. Intercalary meristem:
Intercalary meristem is present at the base of internodes or near nodes. It helps plants regrow after cutting or grazing. Grass grows again after mowing because of intercalary meristem.
Thus, apical meristem increases length, lateral meristem increases girth and intercalary meristem helps in regrowth.
Question 2. Describe the simple permanent tissues in plants.
Answer:
Simple permanent tissues are made up of only one type of cell. They are formed when meristematic cells lose the ability to divide and become specialised. The three main simple permanent tissues are parenchyma, collenchyma and sclerenchyma.
1. Parenchyma:
Parenchyma is made up of living, thin-walled cells. These cells are loosely packed and have intercellular spaces. Parenchyma stores food and may perform photosynthesis in green parts. In aquatic plants, it forms air spaces and helps in floating.
2. Collenchyma:
Collenchyma is made up of living cells with unevenly thickened corners due to pectin deposition. It provides support and flexibility to young stems, leaf stalks and tendrils. It allows plant parts to bend without breaking.
3. Sclerenchyma:
Sclerenchyma is made up of thick-walled cells. Most of these cells are dead. Their walls contain lignin, which makes them hard and strong. Sclerenchyma provides strength and hardness to plant parts like coconut husk, seed coats and walnut shells.
Thus, simple permanent tissues help in storage, support, flexibility and strength.
Question 3. Explain xylem and phloem as complex permanent tissues.
Answer:
Xylem and phloem are called complex permanent tissues because they are made up of more than one type of cell working together to perform a common function.
Xylem:
Xylem transports water and minerals from roots to other parts of the plant. It also provides mechanical support. Xylem is made up of tracheids, vessels, xylem parenchyma and xylem fibres. Tracheids and vessels are tube-like and help in water transport. Xylem fibres provide strength. Xylem parenchyma is the only living component and helps in storage.
Phloem:
Phloem transports food prepared in the leaves to different parts of the plant. It is made up of sieve tubes, companion cells, phloem parenchyma and phloem fibres. Sieve tubes transport food. Companion cells help sieve tubes in loading and unloading sugars. Phloem parenchyma stores food materials, while phloem fibres provide support.
Thus, xylem transports water and minerals, while phloem transports food.
Question 4. Explain the structure and functions of epithelial tissue.
Answer:
Epithelial tissue forms the outer covering of the body and lines internal organs such as the mouth, lungs, blood vessels, stomach and intestine. It is made up of closely packed cells with very little intercellular space.
Different epithelial tissues perform different functions:
Thin epithelial tissue helps in rapid diffusion of gases and liquids. It is found in lungs and blood vessels. Protective epithelium has many layers and protects the body from injury, friction and microbes. It is found in the skin, mouth and oesophagus. Secretory epithelium produces and releases substances like mucus, enzymes, hormones, sweat and saliva. It is found in glands and stomach lining. Sensory epithelium contains receptor cells and helps in smell, taste, sound and balance. Absorptive epithelium helps in absorption of nutrients and water in the small intestine.
Thus, epithelial tissue is important for protection, absorption, secretion, exchange and sensation.
Question 5. Describe connective tissues and their functions.
Answer:
Connective tissues connect, support and protect different parts of the body. They have cells embedded in a matrix. The matrix may be liquid, soft, jelly-like or hard.
Blood is a fluid connective tissue. It transports gases, nutrients, hormones and wastes. It contains plasma, RBCs, WBCs and platelets. RBCs carry oxygen, WBCs fight infection and platelets help in clotting.
Bone is a hard connective tissue. It supports the body, gives shape and protects internal organs. Its matrix contains calcium and phosphorus.
Cartilage is a flexible connective tissue. It is found in the nose, ear and joints. It provides flexibility and cushioning.
Tendon connects muscle to bone and helps in movement.
Ligament connects bone to bone and provides stability to joints.
Thus, connective tissues perform transport, support, protection, movement and connection.
Question 6. Explain the three types of muscular tissues.
Answer:
Muscular tissue helps in movement by contraction and relaxation. There are three main types of muscular tissues: skeletal, smooth and cardiac muscles.
Skeletal muscles:
Skeletal muscles are attached to bones. They are voluntary muscles, which means they work under our conscious control. Their cells are long, cylindrical, unbranched, multinucleate and striated. They help in movements like walking, running and writing.
Smooth muscles:
Smooth muscles are found in internal organs like the stomach and intestine. They are involuntary muscles, so they are not under conscious control. Their cells are spindle-shaped, have one nucleus and do not show striations. They help in slow and continuous movements, such as movement of food in the intestine.
Cardiac muscles:
Cardiac muscles are found only in the heart. They are involuntary and work rhythmically throughout life. Their cells are cylindrical, branched, have one nucleus and show faint striations. They help the heart beat continuously without fatigue.
Question 7. Explain nervous tissue and the structure of a neuron.
Answer:
Nervous tissue is responsible for control and coordination in the body. It helps the body sense changes, process information and respond to stimuli. It is found in the brain, spinal cord and nerves.
The cells of nervous tissue are called neurons. A neuron is specialised to receive, process and transmit messages.
A neuron has three main parts:
1. Cell body:
The cell body contains the nucleus and controls the activities of the neuron.
2. Dendrites:
Dendrites are branch-like structures that receive signals from other neurons.
3. Axon:
The axon is a long fibre that carries messages away from the cell body. It ends in axon terminals, which pass the message to another cell.
Nervous tissue controls voluntary and involuntary activities. For example, it helps us pull our hand away from a hot object and also coordinates heartbeat and breathing rate.
Question 8. Explain the musculoskeletal system and its role in movement.
Answer:
The musculoskeletal system is made up of bones, muscles, joints, cartilage, tendons and ligaments. It helps the body stand upright, move, maintain posture and protect delicate organs.
Bones form the framework of the body. Muscles are attached to bones by tendons. When muscles contract, they pull the bones. This causes movement at joints. Joints are places where two or more bones meet. Ligaments connect bones to bones and provide stability. Cartilage cushions the ends of bones and reduces friction.
Movement occurs under the control of the nervous system. The brain sends signals through nerves to muscles. The muscles contract and pull bones, producing movement.
For example, when we bend our elbow, muscles of the arm contract and relax in a coordinated way. Tendons transmit the force to bones, and the hinge joint at the elbow allows bending.
Thus, bones provide support, muscles produce force, joints allow movement, and nerves control the whole process.
Question 9. Describe the different types of joints with examples.
Answer:
Joints are places where two or more bones meet. They allow different types of movement.
1. Ball and socket joint:
In this joint, the rounded end of one bone fits into a hollow part of another bone. It allows movement in many directions. Examples are shoulder and hip joints.
2. Hinge joint:
This joint allows movement mainly in one direction, like a door hinge. It allows bending and straightening. Examples are elbow and knee joints.
3. Pivot joint:
This joint allows rotation. The joint between the skull and backbone is a pivot joint. It allows the head to move side to side.
4. Fixed joint:
Fixed joints do not allow movement. The bones of the skull are joined by fixed joints. These joints protect the brain, eyes and ears.
Different joints are suited to different movements. This shows that the structure of a joint is related to its function.
Question 10. Explain totipotency and its importance.
Answer:
Totipotency is the ability of a single plant cell to divide and develop into a complete plant under suitable conditions. Such cells are called totipotent cells.
F. C. Steward demonstrated totipotency using carrot phloem cells. He grew these cells in a nutrient medium containing sugars and hormones under suitable conditions. The cells divided to form a mass of cells. Later, they differentiated into roots, shoots and finally a complete plant.
This process involves dedifferentiation and redifferentiation. Dedifferentiation means specialised cells regain the ability to divide. Redifferentiation means these dividing cells become specialised again to form different tissues and organs.
Totipotency is important in plant tissue culture. It helps in producing many plants from a small piece of tissue. It is useful for crop improvement, production of disease-free plants, conservation of rare plants and genetic engineering. It also helps scientists understand growth and development in plants.
