Multiple Choice Questions (MCQs) on the Fundamental Unit of Life
Below are MCQ questions for class 9 biology, with answers covering the important topics from Class 9 Chapter 5 – The Fundamental Unit of Life. These questions will help you practise and prepare effectively for the fundamental unit of life class 9 MCQ online test and other examinations. Attempt these fundamental unit of life class 9 MCQ questions to strengthen your understanding of cells, their structure, and their functions.
1. Which of the following plastids are colourless?
A. Chromoplasts
B. Chloroplasts
C. Leucoplasts
D. All of the above
E. None of the above
Answer: C. Leucoplasts
Explanation: Plastids that do not contain any pigment are known as leucoplasts. Chromoplasts contain pigments other than green (often red, yellow, or orange), and chloroplasts contain the green pigment chlorophyll.
2. An unripe green fruit changes colour when it ripens. The reason is:
A. Chromoplasts change to chlorophyll
B. Chromoplasts change to chromosomes
C. Chromosomes change to chromoplasts
D. Chloroplasts change to chromoplasts
E. None of the above
Answer: D. Chloroplasts change to chromoplasts
Explanation: As fruits ripen, the green chloroplasts often get converted into coloured chromoplasts, which gives the fruit its characteristic ripe colour.
3. The phenomenon in which cytoplasm shrinks in a hypertonic medium is called:
A. Frontolysis
B. Plasmolysis
C. Acidolysis
D. Allolysis
E. None of the above
Answer: B. Plasmolysis
Explanation: In a hypertonic solution, water moves out of the cell due to osmosis, causing the cytoplasm and cell membrane to shrink away from the cell wall, a process known as plasmolysis.
4. ________ is called the energy currency of the cell.
A. Endoplasmic reticulum
B. Oxygen
C. ATP
D. Mitochondria
E. None of the above
Answer: C. ATP
Explanation: Adenosine Triphosphate (ATP) is a molecule that stores and provides energy for many biochemical processes in the cell.
5. ________ is called the powerhouse of the cell.
A. Mitochondria
B. ATP
C. Lysosomes
D. Red blood cells
E. None of the above
Answer: A. Mitochondria
Explanation: Mitochondria are responsible for producing most of the cell’s ATP through the process of cellular respiration, hence known as the powerhouse of the cell.
6. Who coined the term “cell”?
A. Gorbachev
B. Himmler
C. Robert Hooke
D. Antonie van Leeuwenhoek
E. None of the above
Answer: C. Robert Hooke
Explanation: Robert Hooke first observed and described cells in 1665 using a crude microscope. He used the term “cell” when he saw compartment-like structures in a slice of cork.
7. Which of the following statements is incorrect?
A. Cytoplasm is also known as protoplasm
B. Lysosomes are known as the suicide bags of the cell
C. Mitochondria have their DNA
D. All of the above is incorrect
E. None of the above
Answer: A. Cytoplasm is also known as protoplasm
Explanation: Protoplasm includes the cytoplasm and the nucleus. Cytoplasm alone is not referred to as protoplasm. Lysosomes are indeed called suicide bags, and mitochondria possess their DNA.
8. Which of the following is not a function of the vacuole in plants?
A. They store toxic metabolic wastes
B. They help with the process of cell division
C. They help to maintain turgidity
D. They provide structural support
E. None of the above
Answer: B. They help with the process of cell division
Explanation: Plant vacuoles primarily store substances (including waste) and help maintain cell turgidity and structural support. They are not directly responsible for cell division.
9. Where are the essential proteins and lipids required for the cell membrane manufactured?
A. Lysosome
B. Chromosomes
C. Endoplasmic reticulum
D. Mitochondria
E. None of the above
Answer: C. Endoplasmic reticulum
Explanation: The endoplasmic reticulum is involved in the synthesis of proteins (rough ER) and lipids (smooth ER), which are key components of cellular membranes.
10. The process by which water moves through a semi-permeable membrane from a region of higher concentration to a region of lower concentration, thus equalising water concentration, is called:
A. Evaporation
B. Diffusion
C. Osmosis
D. All of the above
E. None of the above
Answer: C. Osmosis
Explanation: Osmosis is a special type of diffusion involving water molecules moving across a semi-permeable membrane.
Additional Short Quiz (Try It Yourself)
Here are a few more of the fundamental unit of life class 9 MCQ questions to test your understanding. The answers are provided right after the questions so you can check and learn immediately.
Which of the following is not a cell organelle?
A. Ribosome
B. Cytoplasm
C. Golgi apparatus
D. Mitochondria
Answer: B. Cytoplasm (It is the fluid medium inside the cell, not considered a membrane-bound organelle.)
Which organelle is known for packaging and dispatching proteins?
A. Golgi apparatus
B. Ribosome
C. Nucleus
D. Endoplasmic reticulum
Answer: A. Golgi apparatus (It modifies, packages, and helps transport proteins to their destination.)
Which of these structures is absent in animal cells?
A. Cell wall
B. Nucleus
C. Cytoplasm
D. Cell membrane
Answer: A. Cell wall (Animal cells do not have a cell wall; it is characteristic of plant cells.)
Which of these is the site of photosynthesis in plant cells?
A. Endoplasmic reticulum
B. Chloroplast
C. Ribosome
D. Lysosome
Answer: B. Chloroplast (It contains chlorophyll for photosynthesis.)
This short quiz allows you to practise the fundamental unit of life class 9 MCQ online test-style questions and reinforce your learning.
Cells are the basic structural and functional units of life, often referred to as the fundamental unit of life. They vary in size, shape, and function but share common organelles such as the nucleus, cytoplasm, mitochondria, endoplasmic reticulum, Golgi apparatus, and others.
Plastids are found in plant cells (chloroplasts, chromoplasts, leucoplasts).
Mitochondria produce energy (ATP).
The endoplasmic reticulum is essential for protein and lipid synthesis.
Golgi apparatus modifies and packages proteins.
Lysosomes help in intracellular digestion.
Vacuoles maintain turgidity and store various substances in plant cells.
The cell membrane regulates the movement of substances in and out of the cell.
The cell wall (in plants) provides rigid support.
Understanding these core concepts will help you solve the fundamental unit of life class 9 MCQ questions and excel in exams.
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FAQs on The Fundamental Unit of Life Class 9 – MCQ Questions and Answers
1. Why is the cell called the fundamental and structural unit of life?
A cell is called the fundamental and structural unit of life because all living organisms are composed of cells, and each individual cell is capable of performing all essential life functions independently. These functions include respiration, nutrition, excretion, and reproduction, making it the most basic building block of any living organism.
2. What types of questions are most important from Chapter 5, The Fundamental Unit of Life, for the CBSE Class 9 exam 2025-26?
For the Class 9 final exams, important questions from this chapter typically cover:
- The differences between prokaryotic and eukaryotic cells.
- The specific structure and function of organelles like the mitochondria, chloroplasts, and nucleus.
- Processes like osmosis and diffusion, particularly the concept of plasmolysis.
- Diagram-based questions requiring identification of parts in a plant or animal cell.
- Function-related reasoning, such as why mitochondria are called the 'powerhouse of the cell' or lysosomes are 'suicide bags'.
3. Why are mitochondria and chloroplasts often called 'semi-autonomous' organelles?
Mitochondria and chloroplasts are referred to as semi-autonomous organelles because they contain their own DNA and ribosomes. This unique feature allows them to synthesise some of their own proteins and replicate independently of the cell's nucleus, granting them a degree of self-governance within the cellular environment. This also provides evidence for the endosymbiotic theory of their origin.
4. What would happen if the plasma membrane of a cell lost its selective permeability?
If a cell's plasma membrane lost its selective permeability, it would become fully permeable. This would be fatal for the cell because it would lose control over what enters and exits. Harmful substances could freely enter, while essential nutrients and ions would leak out, disrupting the cell's internal balance (homeostasis) and leading to its death.
5. What are the three main structural differences between a plant cell and an animal cell?
The three main structural differences are:
- Cell Wall: Plant cells possess a rigid cell wall made of cellulose outside the plasma membrane for support and protection. Animal cells lack a cell wall.
- Vacuoles: Plant cells typically have a single, large central vacuole that maintains turgor pressure. Animal cells may have several small, temporary vacuoles, if any.
- Plastids: Plant cells contain plastids, such as chloroplasts for photosynthesis. Animal cells do not have plastids.
6. How do lysosomes in animal cells and vacuoles in plant cells perform a similar function?
Lysosomes in animal cells contain powerful digestive enzymes to break down cellular waste, foreign particles, and worn-out organelles. In plant cells, the large central vacuole performs a similar digestive role. It stores waste products and contains enzymes that can break them down, effectively acting as the plant cell's waste disposal and recycling system, much like a lysosome.
7. Why are the endoplasmic reticulum and Golgi apparatus often considered part of a single, coordinated system?
The endoplasmic reticulum (ER) and Golgi apparatus are part of the endomembrane system and work in close coordination. The ER synthesises proteins and lipids. These molecules are then transported in vesicles to the Golgi apparatus, which modifies, sorts, and packages them. The Golgi then dispatches these finished products to their final destinations, either inside or outside the cell, making it a highly efficient production and delivery system.
8. What is plasmolysis and why is it generally observed only in plant cells?
Plasmolysis is the shrinking of the protoplast (the cell membrane and its contents) away from the cell wall when a plant cell is placed in a hypertonic solution. This happens because water moves out of the cell via osmosis. It is observable in plant cells because their rigid cell wall remains intact, creating a visible gap. Animal cells lack a cell wall and would simply shrivel up, a process called crenation, without this distinct separation.
