Class 9 SEBA Science Chapter 5 Solutions – The Fundamental Unit of Life (2026–27) | Assam Eduverse
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SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions are prepared by Assam Eduverse strictly according to the latest SEBA / ASSEB syllabus 2026–27. These SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions are created specifically for students searching for SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions that are accurate, updated, and exam-oriented. This page provides complete SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions, making it a reliable and trusted source for SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions based entirely on the official SEBA Class 9 Science textbook.
The SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions explain every concept included in SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions, such as discovery of the cell, cell theory, unicellular and multicellular organisms, plant cell and animal cell structure, cell membrane, nucleus, cytoplasm, mitochondria, endoplasmic reticulum, Golgi apparatus, ribosomes, lysosomes, and vacuoles. These SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions help students understand theory, definitions, diagrams, and reasoning questions using SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions written in simple, clear, and exam-friendly language. Every SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solution strictly follows the official ASSEB Class 9 Science Chapter 5 solutions format and marking scheme.
With the complete SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions (2026–27), students can confidently prepare SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions for intext questions as well as SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions for chapter-end textbook exercise questions. These SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solutions include important The Fundamental Unit of Life question answers, cell structure notes, and exam-focused explanations. Assam Eduverse ensures every SEBA Class 9 Science Chapter 5 The Fundamental Unit of Life solution is syllabus-based, conceptually accurate, and fully exam-focused for SEBA and ASSEB examinations.
SEBA / ASSEB Class 9 Science Chapter 5 – The Fundamental Unit of Life Intext Questions & Answers (Latest Syllabus 2026–27)
📝Page 59
Q1. Who discovered cells, and how?
Answer:
Cells were discovered by Robert Hooke in 1665. He observed thin slices of cork under a self-designed microscope and found that the cork appeared to be made of little boxes or compartments, which he called “cells.”
Q2. Why is the cell called the structural and functional unit of life?
Answer:
Cells are called the structural and functional units of life because they form the basic building blocks of all living organisms. All essential life processes occur within cells, making them responsible for both the structure and functions of the body.
📝Page 61
Q1. How do substances like CO₂ and water move in and out of the cell? Discuss.
Answer:
Substances such as carbon dioxide and water move in and out of the cell through passive transport mechanisms like diffusion and osmosis. CO₂ diffuses out of the cell when its concentration inside is high, and oxygen enters the cell by diffusion when its internal concentration decreases. Water moves across the selectively permeable plasma membrane by osmosis, from regions of higher water concentration to lower concentration.
Q2. Why is the plasma membrane called a selectively permeable membrane?
Answer:
The plasma membrane is called selectively permeable because it allows only certain substances to pass in and out of the cell while restricting the movement of others, thereby maintaining the internal environment of the cell.
📝Page 63
Q1. Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.
Prokaryotic Cell | Eukaryotic Cell | |
1. | Size: generally small (1-10 μm) | Size: generally large (5-100 μm) |
2. | Nuclear region: poorly defined and known as nucleoid | Nuclear region: well defined and surrounded by a nuclear membrane |
3. | Chromosome: single | More than one chromosome |
4. | Membrane-bound cell organelles: absent | Membrane-bound cell organelles: present |
Answer:
- Size: generally small (1–10 μm); Size: generally large (5–100 μm)
- Nuclear region: poorly defined and known as nucleoid; well defined and surrounded by a nuclear membrane
- Chromosome: single; more than one chromosome
- Membrane-bound cell organelles: absent; present
📝Page 65
Q1. Can you name the two organelles we have studied that contain their own genetic material?
Answer:
The two organelles that contain their own genetic material are mitochondria and plastids (specifically, chloroplasts in plant cells).
Q2. If the organisation of a cell is destroyed due to some physical or chemical influence, what will happen?
Answer:
If the organisation of a cell is destroyed, its life processes will stop, and the cell will eventually die because the coordinated functioning of various cell organelles and components is essential for survival.
Q3. Why are lysosomes known as suicide bags?
Answer:
Lysosomes are known as suicide bags because they contain powerful digestive enzymes that can break down all types of organic materials. If they burst within the cell, the enzymes digest their own cell, resulting in its destruction.
Q4. Where are proteins synthesised inside the cell?
Answer:
Proteins are synthesised in ribosomes, which may either float freely in the cytoplasm or be attached to the surface of rough endoplasmic reticulum.
SEBA Class 9 Science Chapter 5 – The Fundamental Unit of Life Textbook Exercise Questions & Solutions | 2026–27
Q1. Make a comparison and write down ways in which plant cells are different from animal cells.
Answer:
Plant cells have a cell wall made of cellulose outside their plasma membrane, chloroplasts for photosynthesis, and usually a large central vacuole whereas Animal cells do not have a cell wall or chloroplasts, and their vacuoles, if present, are small in size.
Q2. How is a prokaryotic cell different from a eukaryotic cell?
Answer:
A prokaryotic cell lacks a well-defined nucleus and membrane-bound organelles; its genetic material is found in a nucleoid region. Eukaryotic cells have a clearly defined nucleus protected by a nuclear membrane and contain various membrane-bound organelles.
Q3. What would happen if the plasma membrane ruptures or breaks down?
Answer:
If the plasma membrane ruptures, the cell’s contents would leak out, and essential nutrients and molecules would escape, ultimately leading to the death of the cell.
Q4. What would happen to the life of a cell if there was no Golgi apparatus?
Answer:
Without the Golgi apparatus, the cell would be unable to properly store, modify, and package substances like proteins and lipids. This would disrupt the transport and secretion of materials, seriously affecting cell function.
Q5. Which organelle is known as the powerhouse of the cell? Why?
Answer:
Mitochondria are known as the powerhouse of the cell because they generate energy in the form of ATP through the process of cellular respiration.
Q6. Where do the lipids and proteins constituting the cell membrane get synthesised?
Answer:
Lipids are synthesised by the smooth endoplasmic reticulum, and proteins are synthesised by ribosomes, which may be attached to the rough endoplasmic reticulum.
Q7. How does an Amoeba obtain its food?
Answer:
Amoeba obtains its food through endocytosis, where it engulfs food particles using its flexible cell membrane to form food vacuoles.
Q8. What is osmosis?
Answer:
Osmosis is the movement of water molecules from a region of higher water concentration to a region of lower water concentration through a selectively permeable membrane.
Q9. Carry out the following osmosis experiment:
Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now:
(a) Keep cup A empty
(b) Put one teaspoon sugar in cup B
(c) Put one teaspoon salt in cup C
(d) Put one teaspoon sugar in the boiled potato cup D.
Keep these for two hours. Then observe the four potato cups and answer the following:
(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment?
(iii) Explain why water does not gather in the hollowed out portions of A and D.
Answer:
(i) Water gathers in the hollowed portions of B and C because the sugar and salt inside create a region of lower water concentration compared to the surrounding water. Water enters by osmosis.
(ii) Potato A serves as a control to show that water will not gather unless there is a difference in concentration (i.e., it is empty and does not draw water in).
(iii) Water does not gather in A because it is empty and there is no solute to create a concentration gradient. It does not gather in D because boiling destroys the living tissues, making the plasma membrane non-functional for osmosis.
Q10. Which type of cell division is required for growth and repair of body and which type is involved in formation of gametes?
Answer:
Mitosis is the type of cell division required for growth and repair of the body, producing identical daughter cells. Meiosis is involved in the formation of gametes, producing cells with half the number of chromosomes.
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