NCERT Science Class 9 Chapter 5 Question Answer Solutions – THE FUNDAMENTAL UNIT OF LIFE FREE PDF Download 2025-26
Page – 51
๐ Q. 1. Who discovered cells, and how? โจ
โก๏ธAnswer:-
๐ฌ Discovery of Cells
๐ Discovered by: Robert Hooke (1665)
๐ง How was it discovered?
Robert Hooke, an English scientist, observed a thin slice of cork (bark of a tree) under a self-designed microscope. He noticed small, box-like structures which he called “cells”, as they resembled the tiny rooms in a monastery, known as cells.
๐ Importance of Hooke’s Discovery:
Although Hooke could only observe dead plant cells, his discovery laid the foundation for cell theory, which later established that all living organisms are made up of cells.
โจ Fun Fact:
The term “cell” comes from the Latin word “cellula”, meaning a small room! ๐
๐ก Conclusion:
Robert Hooke was the first scientist to discover cells in 1665 while examining a cork slice under a microscope, paving the way for modern biology! ๐ฑ๐
Q. 2. Why is the cell called the structural and functional unit of life?
Answer:-
๐งฌ Why is the Cell Called the Structural and Functional Unit of Life?
๐น ๐ Structural Unit:
Cells are the building blocks of all living organisms. Just like bricks form a house ๐ , cells come together to form tissues, organs, and entire organisms.
๐น โ Functional Unit:
Cells carry out all essential life processes such as respiration ๐ฌ, digestion ๐ฝ, excretion ๐ฎ, and reproduction ๐ผ. Each cell works like a tiny factory ensuring survival.
๐น โจ Key Points:
โ
Every living organism is made up of cells.
โ
Cells perform all necessary biological activities.
โ
Specialized cells form different tissues, organs, and systems.
๐ก Conclusion:
Cells are called the structural and functional units of life because they form the basic structure of living organisms and carry out all vital functions required for survival! ๐ฟ๐ฌ
Page – 53
Q. 1. How do substances like CO2 and water move in and out of the cell? Discuss.
Answer:-
๐ฑ Movement of Substances Like COโ and Water In and Out of the Cell
๐น 1. Diffusion ๐ถโโ๏ธ
- COโ and Oโ move in and out of the cell through diffusion.
- Diffusion is the process where molecules move from a higher concentration to a lower concentration until equilibrium is reached.
- Example: Cells produce COโ as a waste product. Since the concentration of COโ is higher inside the cell, it moves out into the surroundings. Conversely, Oโ enters the cell from the surroundings as its concentration is higher outside.
๐น 2. Osmosis ๐ง
- Water moves in and out of the cell through osmosis, a special type of diffusion for water molecules.
- 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.
- Example: If a cell is placed in a hypotonic solution (low solute, high water), water enters the cell, causing it to swell. If placed in a hypertonic solution (high solute, low water), water moves out, causing the cell to shrink.
๐ก Conclusion:
COโ and Oโ move by diffusion while water moves by osmosis, both processes ensuring the exchange of essential substances for cellular survival! ๐ฟ๐ฌ
Q. 2. Why is the plasma membrane called a selectively permeable membrane?
Answer:-
๐งช Why is the Plasma Membrane Called a Selectively Permeable Membrane?
๐น ๐ฌ Definition:
The plasma membrane is called a selectively permeable membrane because it allows only certain substances to enter or exit the cell while blocking others. ๐ชโจ
๐น โ How Does It Work?
The plasma membrane is made up of a phospholipid bilayer ๐ with embedded proteins ๐งฉ. This unique structure helps in selective transport, meaning:
โ
Allows essential molecules like oxygen (Oโ), water (HโO), and nutrients to enter the cell.
โ Restricts harmful substances and prevents the loss of vital components.
๐น ๐ค Methods of Transport:
1๏ธโฃ Passive Transport (๐ถโโ๏ธ No Energy Needed)
- Diffusion: Movement of gases like oxygen and carbon dioxide (COโ). ๐ฌ
- Osmosis: Movement of water molecules. ๐ง
2๏ธโฃ Active Transport (โก Requires Energy) - Transport of ions and large molecules against their concentration gradient. ๐
๐ก Conclusion:
Since the plasma membrane controls what enters and exits, it is selectively permeable, ensuring the cellโs safety and functionality! ๐ฌ๐ฑ
๐ โจ Exam Tips:
โ
Use diagrams ๐ผ to explain the concept clearly.
โ
Mention key transport processes like diffusion, osmosis, and active transport for better marks.
โ
Keep answers concise yet detailed for full marks! โจ๐
Page – 55
Q. 1. Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.

Answer:-
๐ฌ Filled-in Table: Differences Between Prokaryotic and Eukaryotic Cells
Hereโs your completed table with the missing information:
Feature ๐ท๏ธ | Prokaryotic Cell ๐ฆ | Eukaryotic Cell ๐งฌ |
---|---|---|
Size ๐ | Generally small (1-10 ยตm) | Generally large (5-100 ยตm) |
Nuclear Region ๐ฏ | โ Not well defined because of the absense of nuclear membrance and known as nucleoid | โ Well-defined nucleus surrounded by a nuclear membrane |
Chromosome Number ๐งฌ | Single | More than one |
Membrane-bound Organelles ๐ญ | โ Absent | โ Present (e.g., mitochondria, Golgi body, ER) |
๐ก โจ Exam Tips:
โ
Use examples like bacteria (prokaryotic) and plants/animals (eukaryotic) for extra marks! ๐ฑ
โ
Try drawing a simple diagram to make your answer visually appealing ๐ผ๏ธ.
โ
Keep your explanation concise yet detailed to maximize your score! ๐ฏ
Page – 57
Q. 1. Can you name the two organelles we have studied that contain their own genetic material?
Answer:-
๐งฌ Organelles That Contain Their Own Genetic Material
๐น 1. Mitochondria โก
- Known as the “powerhouse of the cell”, mitochondria generate energy (ATP) through cellular respiration. ๐ฅ
- It has its own DNA ๐งฌ and ribosomes, allowing it to replicate independently.
- Found in both plant and animal cells. ๐ฑ๐พ
๐น 2. Chloroplasts ๐ฟ
- Present only in plant cells and some algae, chloroplasts help in photosynthesis, converting sunlight into energy. โ๏ธ
- It also contains its own DNA ๐งฌ and ribosomes, enabling self-replication like mitochondria.
- The green pigment chlorophyll inside chloroplasts captures sunlight. ๐
๐ก โจ Exam Tips:
โ
Mention both organelles and their functions for full marks.
โ
Highlight their ability to replicate independently due to their DNA & ribosomes. ๐ฌ
โ
Use a neat diagram ๐ผ๏ธ in your answer to make it visually appealing!
โ
Keep your explanation concise yet detailed for better clarity.
Q. 2. If the organisation of a cell is destroyed due to some physical or chemical influence, what will happen?
Answer:-
โ ๏ธ Effect of Cell Disorganization Due to Physical or Chemical Influence
๐น ๐ฌ Importance of Cell Organization:
Every living cell functions systematically due to its well-organized structure, where different organelles perform specific roles. ๐๏ธ
๐น ๐จ Consequences of Cell Disorganization:
If a cell’s organization is disturbed due to physical or chemical damage, the following effects occur:
โ
Loss of Function โ๏ธ: Organelles like mitochondria, ribosomes, and the nucleus stop working, affecting cellular activities.
โ
Interruption in Metabolism ๐ฅ: Essential processes like respiration, digestion, and waste removal are disrupted.
โ
Cell Death โ ๏ธ: If the damage is severe and irreversible, the cell loses its ability to survive and eventually dies.
๐น โ ๏ธ Causes of Disorganization:
โ Physical Influence: High temperature, mechanical injury, radiation.
โ Chemical Influence: Toxic substances, strong acids/bases, harmful drugs.
๐ก โจ Exam Tips:
โ
Mention how the loss of cell organization affects essential functions.
โ
Use examples of physical & chemical influences for clarity.
โ
If possible, include a diagram ๐ผ๏ธ illustrating cell disintegration.
โ
Keep answers concise yet well-explained for full marks! โ
๐
Q. 3. Why are lysosomes known as suicide bags?
Answer:-
๐ฆ Why Are Lysosomes Known as Suicide Bags?
๐น ๐ฌ What Are Lysosomes?
Lysosomes are small, membrane-bound organelles filled with digestive enzymes. They help break down waste, damaged organelles, and harmful substances inside the cell. ๐ฎ๐ ๏ธ
๐น โ ๏ธ Why โSuicide Bagsโ?
Lysosomes are called “suicide bags” because:
โ
Self-Destruction Mechanism: When a cell is damaged beyond repair, lysosomes burst, releasing their enzymes. This process leads to self-digestion of the cell. ๐๏ธโกโก
โ
Apoptosis (Programmed Cell Death): Lysosomes help in destroying old or unwanted cells, ensuring proper growth and maintenance of the organism. ๐โ
๐น ๐ Importance of Lysosomes:
โ Help in digestion of cellular waste. ๐ฎ
โ Defend against pathogens (like bacteria). ๐ฆ ๐ก๏ธ
โ Play a vital role in cell renewal. ๐ฑโจ
๐ก โจ Exam Tips:
โ
Explain how lysosomes break down cellular components. ๐ ๏ธ
โ
Mention apoptosis and self-digestion for full marks. โจ
โ
A neat diagram of a lysosome will make your answer stand out! ๐ผ๏ธ
โ
Keep your explanation concise but detailed for clarity. โ
๐
Q. 4. Where are proteins synthesised inside the cell?
Answer:-
๐งฌ Where Are Proteins Synthesized Inside the Cell?
๐น ๐ก Key Organelles Involved:
โ
Ribosomes ๐ญ โ Known as the “protein factories” of the cell, ribosomes assemble amino acids into proteins.
โ
Endoplasmic Reticulum (ER) ๐ฌ โ The rough ER (covered with ribosomes) helps in the processing and transportation of proteins.
โ
Cytoplasm ๐ โ Free ribosomes in the cytoplasm also synthesize proteins that remain within the cell.
๐น โ How Does Protein Synthesis Work?
1๏ธโฃ Transcription ๐ โ DNA is copied into mRNA inside the nucleus.
2๏ธโฃ Translation โ๏ธ โ Ribosomes decode mRNA and assemble amino acids into proteins.
3๏ธโฃ Processing & Transport ๐ โ The rough ER and Golgi apparatus modify and transport proteins to their destinations.
๐ก โจ Exam Tips:
โ
Mention ribosomes as the primary site of protein synthesis for full marks.
โ
Briefly explain transcription and translation for clarity.
โ
Draw a simple diagram ๐ผ๏ธ to represent the process visually!
โ
Keep your answer concise yet detailed to score well.
Back Excercise Questions – Answers
Q. 1. Make a comparison and write down ways in which plant cells are different from animal cells.
Answer:-
๐ฑ๐ฆ Comparison: Plant Cells vs. Animal Cells
๐ Table: Differences Between Plant and Animal Cells
Feature ๐ท๏ธ | Plant Cells ๐ฑ | Animal Cells ๐ฆ |
---|---|---|
Cell Wall ๐๏ธ | โ Present (made of cellulose) | โ Absent |
Shape ๐ท | Generally rectangular | Usually round or irregular |
Chloroplasts ๐ | โ Present (for photosynthesis) | โ Absent |
Vacuole ๐ง | Large central vacuole | Small or absent vacuoles |
Centrioles ๐ | โ Absent | โ Present (helps in cell division) |
Mode of Nutrition ๐ฝ๏ธ | Autotrophic (prepares own food) | Heterotrophic (depends on other organisms) |
Lysosomes โ ๏ธ | Rarely found | โ Present (helps in digestion) |
๐น ๐ก Key Takeaways:
โ Plant cells have a cell wall, chloroplasts, and a large vacuole for storing water. ๐ฟ
โ Animal cells lack a cell wall, lack chloroplasts, and have centrioles for cell division. ๐งฌ
โ Plant cells carry out photosynthesis, while animal cells depend on consuming food. ๐
๐ก โจ Exam Tips:
โ
Use a clear diagram ๐ผ๏ธ comparing plant and animal cells.
โ
Mention examples like leaf cells (plants) and muscle cells (animals). ๐ฑ๐พ
โ
Highlight key differences in cell structure with headings for clarity. ๐
โ
Keep the answer neat, structured, and well-explained to score full marks! โ
๐
Q. 2. How is a prokaryotic cell different from a eukaryotic cell?
Answer:-
๐ฆ Differences Between Prokaryotic and Eukaryotic Cells
Hereโs a structured comparison to help you ace your board exams! ๐๐
๐ Table: Prokaryotic vs. Eukaryotic Cells
Feature ๐ท๏ธ | Prokaryotic Cells ๐ฆ | Eukaryotic Cells ๐งฌ |
---|---|---|
Size ๐ | Small (1-10 ยตm) | Larger (10-100 ยตm) |
Nucleus ๐ฏ | โ No true nucleus (nucleoid present) | โ Well-defined nucleus with a nuclear membrane |
DNA Structure ๐งฌ | Circular, single chromosome | Linear, multiple chromosomes |
Membrane-bound Organelles ๐ญ | โ Absent | โ Present (e.g., mitochondria, Golgi body, ER) |
Cell Division โ | Binary fission (simple division) | Mitosis & meiosis (complex division) |
Examples ๐ | Bacteria, archaea | Plants, animals, fungi, protists |
๐น ๐ก Key Takeaways:
โ Prokaryotic cells are simpler and lack a nucleus, while eukaryotic cells are complex and have membrane-bound organelles. ๐ฌ
โ Prokaryotes reproduce by binary fission, whereas eukaryotes use mitosis & meiosis. โ
โ Examples: Bacteria (prokaryotes) vs. plant and animal cells (eukaryotes). ๐ฑ๐พ
๐ก โจ Exam Tips:
โ
Draw a neat diagram ๐ผ๏ธ comparing both cell types.
โ
Highlight nucleus & organelles as key distinguishing features. ๐ฏ
โ
Keep answers structured with headings for clarity and full marks! โ
๐
Q. 3. What would happen if the plasma membrane ruptures or breaks down?
Answer:-
๐ฉธ What Happens If the Plasma Membrane Ruptures or Breaks Down?
๐น ๐ฌ Importance of the Plasma Membrane:
The plasma membrane (also called the cell membrane) is a selectively permeable layer that protects the cell and regulates the entry and exit of substances. ๐ชโจ
๐น โ Consequences of Rupturing the Plasma Membrane:
โ
Loss of Selective Permeability ๐ โ The cell can no longer control what enters or exits, leading to an imbalance of ions, nutrients, and water.
โ
Leakage of Cytoplasmic Contents ๐ง โ The cytoplasm spills out, affecting vital cellular functions.
โ
Disruption of Cellular Activities โ โ Organelles like mitochondria and ribosomes fail to function properly, stopping respiration and protein synthesis.
โ
Cell Death โ ๏ธ โ If the damage is severe, the cell cannot survive, leading to its destruction.
๐น ๐ก Reasons for Membrane Rupture:
โ Mechanical Injury โ Physical damage like crushing or tearing can break the membrane.
โ Chemical Exposure โ Harmful substances like strong acids or toxins may weaken the membrane.
โ Extreme Temperature โ Very high or low temperatures can damage the lipid bilayer.
๐ก โจ Exam Tips:
โ
Define plasma membrane and highlight its protective function.
โ
Explain why cell survival depends on membrane integrity.
โ
Draw a diagram ๐ผ๏ธ showing cell rupture for better understanding.
โ
Keep your answer structured and precise for full marks! โ
๐
Q. 4. What would happen to the life of a cell if there was no Golgi apparatus?
Answer:-
๐ฆ What Would Happen to a Cell Without the Golgi Apparatus?
๐น ๐ฌ Role of the Golgi Apparatus:
The Golgi apparatus is like the “packaging and distribution center” of the cell. It helps in modifying, sorting, and transporting proteins and lipids to their appropriate destinations. ๐โจ
๐น ๐จ Consequences of Losing the Golgi Apparatus:
โ
Incomplete Protein Processing โ๏ธ โ Proteins produced by the ribosomes would remain unmodified, making them ineffective.
โ
Disrupted Transport System ๐ฆ โ The cell would struggle to send proteins and enzymes to the right locations.
โ
Failure in Secretion ๐ โ Important substances like hormones, enzymes, and mucus wouldnโt be properly released.
โ
Accumulation of Unprocessed Materials ๐ง โ Waste and unprocessed molecules would build up inside the cell, leading to dysfunction.
โ
Cellular Breakdown & Death โ ๏ธ โ Over time, the cell would not function properly and may eventually die due to lack of coordination.
๐น ๐ก Why Is the Golgi Apparatus Essential?
โ It ensures proper transport and delivery of proteins. ๐
โ Helps in forming lysosomes, which digest unwanted materials. ๐ฆ
โ Maintains cell balance by sorting and packaging molecules. ๐ฆ
๐ก โจ Exam Tips:
โ
Explain Golgiโs role in protein modification and transport clearly.
โ
Highlight how the absence of Golgi affects different cellular functions.
โ
Use a neat diagram ๐ผ๏ธ of the Golgi apparatus for better marks!
โ
Keep your answer structured and well-explained to maximize your score. โ
๐
Q. 5. Which organelle is known as the powerhouse of the cell? Why?
Answer:-
โก Which Organelle is Known as the Powerhouse of the Cell?
๐น Mitochondria: The Powerhouse of the Cell ๐ญ
Mitochondria are called the “powerhouse of the cell” because they generate energy (ATP) needed for various cellular activities. They play a crucial role in cellular respiration, where glucose is broken down to release energy. ๐ฅ
๐น ๐ฌ Why Are Mitochondria So Important?
โ
ATP Production: Mitochondria convert nutrients into adenosine triphosphate (ATP), the energy currency of the cell. ๐ก
โ
Double Membrane Structure: Their inner membrane has folds called cristae, which increase the surface area for energy production. ๐๏ธ
โ
Contains Its Own DNA: Mitochondria have their own genetic material, allowing them to replicate independently. ๐งฌ
๐น ๐ Process of Energy Production:
1๏ธโฃ Glycolysis โ Breakdown of glucose outside the mitochondria. ๐โก๏ธโก
2๏ธโฃ Krebs Cycle โ Further breakdown in the mitochondrial matrix. ๐
3๏ธโฃ Electron Transport Chain โ Major ATP synthesis occurs here. ๐
๐ก โจ Exam Tips:
โ
Clearly mention ATP production as the main function.
โ
Explain mitochondrial structure with key terms like cristae and double membrane. ๐๏ธ
โ
Draw a simple diagram of mitochondria ๐ผ๏ธ to enhance your answer.
โ
Keep your explanation concise but well-detailed to score full marks! ๐
Q. 6. Where do the lipids and proteins constituting the cell membrane get synthesised?
Answer:-
๐งช Where Are the Lipids and Proteins Constituting the Cell Membrane Synthesized?
๐น ๐ฌ Lipid Synthesis: Endoplasmic Reticulum (ER)
โ
Lipids, the essential components of the plasma membrane, are synthesized in the Smooth Endoplasmic Reticulum (SER). ๐๏ธ
โ
The SER helps in the formation of phospholipids, which are crucial for membrane fluidity and structure. ๐
๐น โ Protein Synthesis: Ribosomes & Rough ER
โ
Proteins needed for the plasma membrane are synthesized by ribosomes, the โprotein factoriesโ of the cell. ๐ญ
โ
Rough Endoplasmic Reticulum (RER) processes these proteins and transports them for incorporation into the membrane. ๐
๐น ๐ Modification & Transport: Golgi Apparatus
โ
The Golgi body further modifies and packages proteins and lipids into vesicles for transport to the cell membrane. ๐ฆ
๐ก โจ Exam Tips:
โ
Clearly mention SER for lipids and RER + ribosomes for proteins.
โ
Highlight Golgi bodyโs role in processing & transport. ๐
โ
Draw a simple diagram ๐ผ๏ธ illustrating lipid and protein synthesis pathways.
โ
Keep the explanation concise, structured, and well-explained for full marks! ๐โ
Q. 7. How does an Amoeba obtain its food?
Answer:-
๐ฆ How Does an Amoeba Obtain Its Food?
Amoeba is a unicellular organism that feeds through a special process called phagocytosis. Letโs break it down step by step! ๐
๐น 1. Detection of Food ๐
- Amoeba senses its food, such as bacteria or microscopic organisms, in its surrounding water. ๐
๐น 2. Formation of Pseudopodia โ
- It extends finger-like projections called pseudopodia (meaning “false feet”) around the food particle. ๐๏ธ
- The food gets enclosed within these pseudopodia, forming a food vacuole.
๐น 3. Digestion Inside Food Vacuole ๐ฝ๏ธ
- Enzymes from the cytoplasm break down the food inside the food vacuole. ๐งช
- The nutrients are absorbed into the cytoplasm, providing energy to the Amoeba. โก
๐น 4. Excretion of Waste ๐ฎ
- After digestion, the undigested food is expelled out of the cell through the cell membrane. ๐ช
๐ก โจ Exam Tips:
โ
Use a labeled diagram ๐ผ๏ธ of Amoeba engulfing food.
โ
Highlight pseudopodia and food vacuole formation as key points. โ๏ธ
โ
Keep the answer well-structured, concise, and scientifically accurate. ๐โ
โ
Mention phagocytosis as the main process! ๐
Q. 8. What is osmosis?
Answer:-
๐ง Osmosis: The Special Type of Diffusion
๐น ๐ฌ Definition:
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. ๐โจ
๐น โ Importance of Osmosis:
โ
Maintains water balance in cells. โ๏ธ
โ
Helps in the absorption of nutrients in plants. ๐ฑ
โ
Plays a crucial role in exchange of fluids in organisms. ๐งฌ
๐น ๐ Types of Solutions Affecting Osmosis:
1๏ธโฃ Hypotonic Solution ๐ฆ โ Higher water concentration outside the cell โ Water moves inside โ Cell swells. ๐ก๐
2๏ธโฃ Hypertonic Solution ๐ฅ โ Higher water concentration inside โ Water moves out โ Cell shrinks. ๐
3๏ธโฃ Isotonic Solution โ๏ธ โ Equal water concentration โ No net movement โ Cell stays normal. โ
๐ก โจ Exam Tips:
โ
Always define osmosis clearly and mention the selectively permeable membrane.
โ
Include real-life examples like plant root absorption and RBC shrinkage in saline water. ๐ฑ๐ฉธ
โ
Use a neat diagram ๐ผ๏ธ showing water movement in different solutions.
โ
Keep your answer concise but well-explained to score full marks! ๐โ
Q. 9. Carry out the following osmosis experiment:
Take four peeled potato halves and scoos 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:-
๐ฌ Osmosis Experiment Using Potato Cups
๐ Observation & Explanation:
(i) Why does water gather in the hollowed portion of B and C?
โ
Sugar in cup B and salt in cup C create a hypertonic solution, meaning the concentration of solutes inside the cups is higher than outside. ๐๏ธ
โ
Due to osmosis, water from the surrounding moves into the hollowed portions to balance the concentration. ๐งโก๏ธ๐ฅ
(ii) Why is potato A necessary for this experiment?
โ
Potato A serves as a control to compare changes caused by osmosis. ๐ฏ
โ
Since it is empty, there is no concentration difference, preventing water movement. ๐โ
(iii) Why does water not gather in the hollowed portions of A and D?
โ
In cup A, there is no solute to create a concentration difference, so osmosis does not occur. ๐ซ๐ง
โ
In cup D, the potato is boiled, damaging its cell membranes, making it unable to perform osmosis effectively. ๐ฅ๐ฅโก๏ธโ
๐ก โจ Exam Tips:
โ
Define osmosis clearly with mention of selectively permeable membranes. ๐ฌ
โ
Explain hypertonic solutions and why they cause water movement. ๐ง๐
โ
Draw a neat diagram ๐ผ๏ธ illustrating the experiment for better clarity.
โ
Keep the answer concise, structured, and well-explained for full marks! โ
๐
Q. 10. Which type of cell division is required for growth and repair of body and which type is involved in formation of gametes?
Answer:-
๐งฌ Types of Cell Division: Growth vs. Gamete Formation
Cell division is essential for the survival of organisms, and it occurs in two major forms: Mitosis and Meiosis. Letโs break them down for clarity! ๐
๐น 1. Mitosis โ For Growth & Repair ๐๏ธ
โ
Mitosis helps in the growth, repair, and replacement of damaged cells.
โ
It occurs in somatic cells (body cells).
โ
Produces two identical daughter cells with the same number of chromosomes as the parent cell.
โ
Example: Healing of wounds, growth of tissues, replacement of old cells. ๐ฑโจ
๐น 2. Meiosis โ For Gamete Formation ๐
โ
Meiosis is responsible for the production of gametes (sperm & egg) in sexually reproducing organisms.
โ
Occurs in reproductive cells (gonads).
โ
Produces four daughter cells, each containing half the number of chromosomes (haploid).
โ
Ensures genetic variation among offspring. ๐งฌ
๐ก โจ Exam Tips:
โ
Clearly differentiate mitosis for growth/repair and meiosis for gamete formation.
โ
Mention chromosome number differences (diploid vs. haploid).
โ
Use a neat diagram ๐ผ๏ธ of both processes for better clarity.
โ
Keep answers structured and well-explained to score full marks! ๐โ