Cell and Tissues – Long Answer Questions
Medium Level (Application & Explanation)
Q1. Explain why we say all living organisms are made of cells. How do unicellular and multicellular organisms differ?
Answer:
- All living things are made of cells. Cells are the basic units of life.
- A unicellular organism has only one cell. That one cell does all the life processes.
- Example: Amoeba moves, eats, respires, and excretes using the same cell.
- A multicellular organism has many cells. Different cells do different jobs.
- This is called division of labour. It makes work faster and better.
- Example: Humans have muscle, nerve, and blood cells with special roles.
- So, one cell is enough for a small body. Many cells are needed for a complex body.
Q2. Describe the roles of muscle cells, nerve cells, and blood in humans. How do they show division of labour?
Answer:
- Muscle cells can contract and relax. They help in movement of body parts.
- Nerve cells carry messages. They send signals from brain to muscles and organs.
- Blood is a fluid tissue. It transports oxygen, food, hormones, and waste.
- Each type of cell does a specific function. They do not do each other’s jobs.
- This is division of labour in a multicellular body.
- It makes work efficient and organized.
- Together, they keep the body active, coordinated, and healthy.
Q3. What is a tissue? Why are tissues important in multicellular organisms? Give examples.
Answer:
- A tissue is a group of similar cells that work together.
- These cells do a particular function as a team.
- In multicellular organisms, tissues make work faster and more efficient.
- They save energy and avoid confusion between tasks.
- Examples: Muscle tissue helps in movement. Blood transports materials.
- Phloem carries food in plants.
- Thus, tissues are the base for organs and systems in the body.
Q4. Explain plant vascular tissues. How do xylem and phloem help the plant survive?
Answer:
- Plants have vascular tissues for transport.
- Xylem carries water and minerals from roots to leaves.
- Phloem carries food made in leaves to other parts.
- This transport runs through the whole plant.
- It supports growth, storage, and repair.
- Without xylem and phloem, the plant would wilt and starve.
- They show division of labour inside the plant body.
Q5. How are basic life functions done in Amoeba compared to humans?
Answer:
- In Amoeba, one cell does movement, feeding, gaseous exchange, and excretion.
- It uses pseudopodia to move and capture food.
- Gases enter and leave by diffusion through the cell surface.
- Wastes are thrown out by the same single cell.
- In humans, many specialized cells share the work.
- Muscle moves, nerve signals, blood transports, and kidneys excrete.
- This division of labour makes complex life possible.
High Complexity (Analysis & Scenario-Based)
Q6. A person has heavy blood loss in an accident. Predict the effects on body functions. Explain using the idea of division of labour.
Answer:
- Blood carries oxygen to cells. Low blood means low oxygen for tissues.
- It carries food from the gut and hormones from glands. These supplies get reduced.
- It removes waste like carbon dioxide and urea. Wastes may build up.
- Organs like brain and muscles work poorly due to low oxygen.
- This shows division of labour: blood’s transport role supports all cells.
- First aid needs stopping bleeding and restoring fluids/blood.
- Quick care prevents organ failure and shock.
Q7. A plant has drooping leaves and swelling of sugary tissues near leaves. Which vascular tissue is likely blocked? Explain.
Answer:
- Drooping leaves suggest poor water supply to leaves.
- Swelling with sugars near leaves suggests food is not moving down.
- Phloem carries food from leaves to other parts. A phloem block causes sugar build-up.
- Xylem carries water upward. If xylem is weak, leaves can also droop.
- Here, the key sign is sugar accumulation near leaves. So phloem is likely blocked.
- The plant may have normal water uptake but cannot send food to roots and stem.
- Over time, roots starve, and the whole plant weakens.
Q8. Why can multicellular organisms grow large, while unicellular organisms remain small? Analyze using surface area and division of labour.
Answer:
- A single cell has limited surface area to exchange materials.
- As size increases, volume grows faster than surface area.
- So, a large single cell cannot get enough oxygen or food quickly.
- Multicellular bodies solve this with many cells and tissues.
- They develop transport systems like blood, xylem, and phloem.
- They use division of labour to share tasks and increase efficiency.
- Thus, multicellular organisms can grow large and complex.
Q9. A nerve cell to a hand muscle is damaged. What changes will you see in movement? Explain the pathway and role of tissues.
Answer:
- Nerve cells carry signals from the brain to the muscle.
- If the nerve is damaged, signals do not reach the muscle.
- The muscle cannot contract at the right time.
- The hand shows weak or no movement, or poor coordination.
- This shows how nerve tissue and muscle tissue work together.
- It is division of labour: nerves command, muscles act.
- Recovery needs rest, therapy, or repair of the nerve pathway.
Q10. “Blood is a tissue even though it is liquid.” Do you agree? Justify with structure and function.
Answer:
- Yes, blood is a tissue. A tissue is a group of similar cells doing a function.
- Blood has RBCs, WBCs, and platelets in a fluid called plasma.
- Together they do transport, defence, and clotting.
- They act as one unit to support the whole body.
- Its liquid state helps flow to every cell.
- It shows clear division of labour within the tissue.
- So, blood fits the definition of a tissue fully.