Cell Theory Explained: Schleiden, Schwann and Virchow Notes for NEET
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Cell Theory and Overview of Cell showing plant cell, animal cell, nucleus, cytoplasm and membrane-bound organelles. |
Cell Theory & Overview of Cell (NEET Notes for Beginners)
1. Development of Cell Theory
🧑🔬 Matthias Schleiden (1838)
- German botanist.
- Studied plant tissues.
- Concluded that all plants are made up of cells.
🧑🔬 Theodor Schwann (1839)
- German zoologist.
- Studied animal cells.
- Observed a thin outer boundary in animal cells, now called the plasma membrane (cell membrane).
- Found that cell wall is present only in plant cells.
- Concluded that animals and plants are composed of cells and cell products.
📖 Cell Theory by Schleiden and Schwann
They proposed that:
- All living organisms are made up of cells.
- Cells are the basic structural units of life.
🧑🔬 Rudolf Virchow (1855)
- Explained how new cells are formed.
- Proposed:
"Omnis Cellula e Cellula" → All cells arise from pre-existing cells.
He modified the original cell theory and gave it its final form.
Final Cell Theory (NEET Important)
1. All living organisms are composed of cells and cell products.
2. All cells arise from pre-existing cells.
⭐ NEET One-Liner
Cell = Basic structural and functional unit of life.
2. Overview of Cell
A cell consists of three main parts:
1. Cell Envelope (Outer Covering)
2. Cytoplasm
3. Nucleus
Plant Cell vs Animal Cell
| Feature | Plant Cell | Animal Cell |
|---|---|---|
| Cell Wall | Present | Absent |
| Plasma Membrane | Present | Present |
| Nucleus | Present | Present |
| Centrosome | Usually Absent | Present |
Cell Wall
Present in:
- Plants
- Fungi
- Bacteria
Absent in:
- Animal cells
Functions:
- Provides shape.
- Gives protection.
- Prevents bursting of cell.
NEET Fact:
Cell wall is a unique feature of plant cells according to Schwann.
Plasma Membrane (Cell Membrane)
- Thin, living boundary of the cell.
- Present in both plant and animal cells.
- Controls movement of substances into and out of the cell.
Function:
✅ Selectively permeable membrane.
Nucleus
Definition
A dense, membrane-bound structure present inside the cell.
Functions
- Controls all cellular activities.
- Contains hereditary material (DNA).
- Responsible for inheritance.
Contains:
➡ Chromosomes
➡ DNA (Genetic Material)
Prokaryotic and Eukaryotic Cells
Prokaryotic Cells
Characteristics:
- No membrane-bound nucleus.
- No membrane-bound organelles.
- DNA lies freely in cytoplasm.
Examples:
- Bacteria
- Cyanobacteria
- Mycoplasma
Diagram Formula:
Prokaryote = No true nucleus
Eukaryotic Cells
Characteristics:
- Membrane-bound nucleus present.
- Membrane-bound organelles present.
Examples:
- Plants
- Animals
- Fungi
- Protists
Diagram Formula:
Eukaryote = True nucleus + Organelles
Cytoplasm
Definition
A semi-fluid matrix filling the cell.
Functions
- Site of most metabolic reactions.
- Maintains the living state of the cell.
- Contains cell organelles.
NEET Point:
Cytoplasm is present in both prokaryotic and eukaryotic cells.
Cell Organelles
Membrane-bound structures performing specific functions.
Major Organelles in Eukaryotic Cells
| Organelle | Function |
|---|---|
| Endoplasmic Reticulum (ER) | Transport and synthesis |
| Golgi Complex | Packaging and secretion |
| Lysosomes | Intracellular digestion |
| Mitochondria | ATP production (Powerhouse) |
| Microbodies | Specialized metabolic functions |
| Vacuoles | Storage |
Important
❌ Prokaryotic cells lack membrane-bound organelles.
Ribosomes
Special Feature
- Non-membrane bound organelles.
- Present in both prokaryotic and eukaryotic cells.
Location
- Cytoplasm
- Rough ER
- Mitochondria
- Chloroplasts
Function
✅ Protein synthesis
NEET Question Favourite
Which organelle is present in both prokaryotes and eukaryotes? ➡ Ribosome
Centrosome
Present In
- Animal cells
Absent In
- Most higher plant cells
Function
- Helps in cell division.
- Forms spindle fibres during mitosis.
NEET One-Liner
Centrosome = Cell division organizer
Cell Size (NEET Fact)
Smallest Cell
➡ Mycoplasma
- Size ≈ 0.3 μm
Examples of Larger Cells
- Bacterial cells are larger than Mycoplasma.
- Egg cells are among the largest cells.
Quick Revision Table
| Scientist | Contribution |
|---|---|
| Schleiden (1838) | All plants are made of cells |
| Schwann (1839) | All animals are made of cells; discovered plasma membrane concept |
| Virchow (1855) | Cells arise from pre-existing cells |
NEET Rapid Fire
✅ Cell theory formulated by → Schleiden and Schwann
✅ "Omnis Cellula e Cellula" given by → Virchow
✅ Genetic material present in → DNA
✅ Site of metabolic activities → Cytoplasm
✅ Protein synthesis → Ribosomes
✅ Powerhouse of cell → Mitochondria
✅ Cell division in animal cells → Centrosome
✅ Smallest known cell → Mycoplasma
✅ Cell wall present in → Plant cells
✅ Membrane-bound nucleus absent in → Prokaryotes
Mnemonic for Cell Theory Scientists
"SSV"
- Schleiden → Plants
- Schwann → Animals
- Virchow → New cells from old cells
Remember:
Plants + Animals + New Cells = Cell Theory 🌱🐾➡️🔬
Cell Theory and Overview of Cell – Easy NEET Notes (Line-by-Line Explanation)
1. Schwann's Contribution (1839)
Schwann (1839), a German Zoologist, studied different types of animal cells.
- Theodor Schwann was a German scientist who studied animal tissues.
- He observed that animal bodies are made up of cells.
He reported that cells had a thin outer layer which is today known as the ‘plasma membrane’.
- Schwann discovered a thin covering around animal cells.
- This covering is now called the plasma membrane (cell membrane).
- It controls the movement of substances into and out of the cell.
He also concluded, based on his studies on plant tissues, that the presence of cell wall is a unique character of plant cells.
- Schwann compared plant and animal cells.
- He found that plant cells have a cell wall, while animal cells do not.
- Therefore, the cell wall is a characteristic feature of plant cells.
On the basis of this, Schwann proposed the hypothesis that the bodies of animals and plants are composed of cells and products of cells.
- Schwann suggested that all plants and animals are made of:
- Cells
- Products formed by cells
NEET Point
✅ Schwann discovered plasma membrane in animal cells.
✅ Cell wall is present only in plant cells.
2. Formation of Cell Theory
Schleiden and Schwann together formulated the cell theory.
- Matthias Schleiden studied plants.
- Theodor Schwann studied animals.
- Together they proposed the Cell Theory.
Contribution of Schleiden
- All plants are made up of cells.
Contribution of Schwann
- All animals are made up of cells.
3. Limitation of Early Cell Theory
This theory however, did not explain as to how new cells were formed.
- The original cell theory could not explain:
- Where new cells come from.
- How cells are produced.
NEET Point
❌ Original Cell Theory lacked explanation about origin of cells.
4. Virchow's Contribution (1855)
Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells.
- Rudolf Virchow solved the missing part of cell theory.
- He stated that:
- Existing cells divide.
- New cells are produced from old cells.
(Omnis cellula e cellula)
- Latin phrase.
- Meaning:
- "Every cell arises from a pre-existing cell."
NEET Point
👉 Omnis cellula e cellula = Every cell comes from another cell.
He modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape.
- Virchow added the concept of cell division.
- This completed the Cell Theory.
Final Cell Theory
(i) All living organisms are composed of cells and products of cells.
Easy Meaning:
- Every living organism consists of:
- One or more cells.
- Cell products.
Examples:
- Amoeba → one cell.
- Human → trillions of cells.
(ii) All cells arise from pre-existing cells.
Easy Meaning:
- New cells are never formed spontaneously.
- They are produced by division of already existing cells.
NEET PYQ Fact
✅ Cell Theory:
- Organisms are made of cells.
- Cells arise from pre-existing cells.
8.3 Overview of Cell
Observation of Cells
You have earlier observed cells in an onion peel and/or human cheek cells under the microscope.
- Onion peel cell = plant cell.
- Cheek cell = animal cell.
- Both can be viewed under a microscope.
Structure of Onion Cell (Plant Cell)
The onion cell which is a typical plant cell, has a distinct cell wall as its outer boundary.
- The outermost covering is the cell wall.
- Cell wall provides:
- Shape
- Protection
- Rigidity
Just within it is the cell membrane.
- Cell membrane lies inside the cell wall.
- It regulates transport of substances.
Arrangement
Cell Wall → Cell Membrane → Cytoplasm
Structure of Human Cheek Cell (Animal Cell)
The cells of the human cheek have an outer membrane as the delimiting structure of the cell.
- Animal cells lack a cell wall.
- Their outer boundary is only the plasma membrane.
NEET Difference
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Cell membrane inside wall | Cell membrane outermost |
Nucleus
Inside each cell is a dense membrane-bound structure called nucleus.
- Nucleus is the control center of the cell.
- It is surrounded by a nuclear membrane.
Functions
- Controls cell activities.
- Stores genetic information.
Chromosomes and DNA
This nucleus contains the chromosomes.
- Chromosomes are present inside the nucleus.
Which in turn contain the genetic material, DNA.
- DNA carries hereditary information.
- DNA determines traits and characteristics.
Sequence to Remember
Cell → Nucleus → Chromosome → DNA
Prokaryotic and Eukaryotic Cells
Eukaryotic Cells
Cells that have membrane-bound nuclei are called eukaryotic.
- True nucleus present.
- Nuclear membrane present.
Examples
- Plants
- Animals
- Fungi
- Protists
Prokaryotic Cells
Cells that lack a membrane-bound nucleus are prokaryotic.
- True nucleus absent.
- Genetic material lies freely in cytoplasm.
Examples
- Bacteria
- Cyanobacteria
- Mycoplasma
NEET Trick
Eu = True → True nucleus present Pro = Primitive → True nucleus absent
Cytoplasm
In both prokaryotic and eukaryotic cells, a semi-fluid matrix called cytoplasm occupies the volume of the cell.
- Cytoplasm is jelly-like material.
- It fills the interior of the cell.
Function
- Site of many cellular reactions.
The cytoplasm is the main arena of cellular activities.
- Most metabolic activities occur here.
Examples:
- Respiration
- Protein synthesis
- Enzyme reactions
Cell Organelles
Besides the nucleus, eukaryotic cells have other membrane-bound structures called organelles.
- Organelles are specialized structures.
- Each performs a specific function.
Membrane-Bound Organelles
- Endoplasmic Reticulum (ER)
- Golgi Complex
- Lysosomes
- Mitochondria
- Microbodies
- Vacuoles
Important Functions
Endoplasmic Reticulum (ER)
- Transport system of cell.
Golgi Complex
- Packaging and secretion.
Lysosomes
- Digestive bags.
- "Suicidal bags of cell."
Mitochondria
- ATP production.
- "Powerhouse of cell."
Vacuoles
- Storage of water and food.
Prokaryotes Lack Organelles
The prokaryotic cells lack such membrane-bound organelles.
- No ER
- No Golgi body
- No mitochondria
- No lysosomes
NEET Point
✅ Membrane-bound organelles absent in prokaryotes.
Ribosomes
Ribosomes are non-membrane-bound organelles found in all cells.
- Present in both:
- Prokaryotes
- Eukaryotes
Function
- Site of protein synthesis.
Ribosomes are found in cytoplasm, chloroplasts, mitochondria and on rough ER.
- Free ribosomes → cytoplasm.
- Attached ribosomes → Rough ER.
- Also present in:
- Mitochondria
- Chloroplasts
NEET Favorite Question
✅ Ribosomes are present in both prokaryotic and eukaryotic cells.
Centrosome
Animal cells contain another non-membrane-bound organelle called centrosome.
- Found mainly in animal cells.
Function
- Helps in cell division.
- Forms spindle fibres.
NEET Point
✅ Centrosome present in animal cells. ❌ Usually absent in higher plant cells.
Cell Size Variation
Cells differ greatly in size, shape and activities.
- Not all cells look alike.
- Different cells perform different functions.
Examples:
- Nerve cell → long
- RBC → circular
- Muscle cell → elongated
Mycoplasma
Mycoplasmas are the smallest cells.
- Smallest living cells known.
- Size ≈ 0.3 μm
NEET Fact
✅ Mycoplasma = Smallest living cell.
Quick NCERT NEET Revision
Scientists and Contributions
| Scientist | Contribution |
|---|---|
| Schleiden (1838) | Plants made of cells |
| Schwann (1839) | Animals made of cells; plasma membrane |
| Virchow (1855) | Cells arise from pre-existing cells |
Cell Theory
- All organisms are made of cells and cell products.
- All cells arise from pre-existing cells.
Key Differences
| Prokaryote | Eukaryote |
|---|---|
| No true nucleus | True nucleus present |
| No membrane-bound organelles | Organelles present |
| Smaller | Larger |
One-Line NEET Facts
- Cell wall → plant cells only.
- Plasma membrane → all cells.
- DNA → genetic material.
- Ribosomes → protein synthesis.
- Mitochondria → powerhouse of cell.
- Lysosomes → suicidal bags.
- Centrosome → cell division in animal cells.
- Mycoplasma → smallest living cell.
- Omnis cellula e cellula → every cell arises from a pre-existing cell.
CELL THEORY & OVERVIEW OF CELL
│
├── CELL THEORY
│ │
│ ├── Schleiden (1838)
│ │ └── All plants are made of cells
│ │
│ ├── Schwann (1839)
│ │ ├── All animals are made of cells
│ │ ├── Discovered plasma membrane in animal cells
│ │ ├── Cell wall is unique to plant cells
│ │ └── Organisms are made of cells and cell products
│ │
│ ├── Virchow (1855)
│ │ ├── Omnis cellula e cellula
│ │ └── New cells arise from pre-existing cells
│ │
│ └── Final Cell Theory
│ ├── All living organisms are composed of cells
│ └── All cells arise from pre-existing cells
│
├── OVERVIEW OF CELL
│ │
│ ├── Plant Cell (Onion Cell)
│ │ ├── Cell Wall (outermost)
│ │ ├── Cell Membrane
│ │ ├── Cytoplasm
│ │ └── Nucleus
│ │
│ ├── Animal Cell (Cheek Cell)
│ │ ├── Cell Membrane (outermost)
│ │ ├── Cytoplasm
│ │ └── Nucleus
│ │
│ └── Common Structures
│ ├── Plasma Membrane
│ ├── Cytoplasm
│ ├── Nucleus
│ ├── Chromosomes
│ └── DNA
│
├── NUCLEUS
│ │
│ ├── Membrane-bound structure
│ ├── Control centre of cell
│ ├── Contains chromosomes
│ └── Chromosomes contain DNA
│
├── TYPES OF CELLS
│ │
│ ├── Prokaryotic Cells
│ │ ├── No true nucleus
│ │ ├── No membrane-bound organelles
│ │ └── Example: Bacteria, Mycoplasma
│ │
│ └── Eukaryotic Cells
│ ├── True nucleus present
│ ├── Membrane-bound organelles present
│ └── Example: Plants, Animals, Fungi
│
├── CYTOPLASM
│ │
│ ├── Semi-fluid matrix
│ ├── Occupies cell volume
│ └── Site of metabolic activities
│
├── CELL ORGANELLES
│ │
│ ├── Membrane-Bound Organelles
│ │ │
│ │ ├── Endoplasmic Reticulum (ER)
│ │ │ └── Transport system
│ │ │
│ │ ├── Golgi Complex
│ │ │ └── Packaging & secretion
│ │ │
│ │ ├── Lysosomes
│ │ │ └── Intracellular digestion
│ │ │
│ │ ├── Mitochondria
│ │ │ └── ATP production (Powerhouse)
│ │ │
│ │ ├── Vacuoles
│ │ │ └── Storage
│ │ │
│ │ └── Microbodies
│ │
│ └── Non-Membrane Bound Organelles
│ │
│ ├── Ribosomes
│ │ ├── Protein synthesis
│ │ ├── Present in all cells
│ │ ├── Cytoplasm
│ │ ├── Rough ER
│ │ ├── Mitochondria
│ │ └── Chloroplast
│ │
│ └── Centrosome
│ ├── Present in animal cells
│ └── Helps in cell division
│
├── CELL SIZE & SHAPE
│ │
│ ├── Cells differ in
│ │ ├── Size
│ │ ├── Shape
│ │ └── Function
│ │
│ └── Example
│ ├── Nerve Cell → Long
│ ├── RBC → Circular
│ └── Muscle Cell → Elongated
│
└── IMPORTANT NEET FACTS
│
├── Smallest living cell → Mycoplasma
├── Genetic material → DNA
├── Powerhouse of cell → Mitochondria
├── Protein synthesis → Ribosomes
├── Cell division (animal cell) → Centrosome
├── Plant-specific structure → Cell Wall
├── Universal cell boundary → Plasma Membrane
└── Omnis cellula e cellula → Every cell from a pre-existing cell
CBSE Class 11 Biology
Cell Theory & Overview of Cell – Question Bank with Answers
A. MCQs (1 Mark Each)
1. Who proposed that all plants are composed of cells?
a) Schwann
b) Virchow
c) Schleiden
d) Hooke
Answer: c) Schleiden
2. Who discovered that animals are made up of cells?
a) Virchow
b) Schwann
c) Hooke
d) Brown
Answer: b) Schwann
3. "Omnis cellula e cellula" was proposed by:
a) Schleiden b) Schwann c) Virchow d) Hooke
Answer: c) Virchow
4. Genetic material is present in:
a) Cytoplasm b) Cell wall c) Chromosomes d) Vacuole
Answer: c) Chromosomes
5. Membrane-bound nucleus is present in:
a) Prokaryotes b) Viruses c) Eukaryotes d) Bacteria
Answer: c) Eukaryotes
6. Which organelle is present in both prokaryotes and eukaryotes?
a) Mitochondria b) Golgi body c) Ribosome d) Lysosome
Answer: c) Ribosome
7. Smallest living cells are:
a) Bacteria b) Amoeba c) Mycoplasma d) Virus
Answer: c) Mycoplasma
8. Centrosome is found mainly in:
a) Plant cells b) Animal cells c) Bacterial cells d) Fungal cells
Answer: b) Animal cells
9. Cell wall is absent in:
a) Onion cell b) Plant cell c) Animal cell d) Algae
Answer: c) Animal cell
10. The powerhouse of the cell is:
a) Golgi body b) Ribosome c) Lysosome d) Mitochondria
Answer: d) Mitochondria
B. Very Short Answer Questions (1 Mark)
1. Who gave the final shape to cell theory?
Answer: Rudolf Virchow.
2. What is plasma membrane?
Answer: A thin living membrane surrounding the cell.
3. What is the genetic material of the cell?
Answer: DNA.
4. Name the smallest living cell.
Answer: Mycoplasma.
5. Name the organelle responsible for protein synthesis.
Answer: Ribosome.
6. Define cytoplasm.
Answer: Semi-fluid matrix present inside the cell where metabolic activities occur.
7. What is a eukaryotic cell?
Answer: A cell having a membrane-bound nucleus.
8. What is a prokaryotic cell?
Answer: A cell lacking a membrane-bound nucleus.
C. Short Answer Questions (2–3 Marks)
1. State the Cell Theory.
Answer:
- All living organisms are composed of cells and cell products.
- All cells arise from pre-existing cells.
2. Differentiate between prokaryotic and eukaryotic cells.
| Prokaryotic | Eukaryotic |
|---|---|
| No true nucleus | True nucleus present |
| No membrane-bound organelles | Organelles present |
| Smaller | Larger |
3. What are chromosomes?
Answer: Chromosomes are thread-like structures present in the nucleus. They contain DNA and carry hereditary information.
4. Why is cytoplasm called the site of cellular activities?
Answer: Most biochemical and metabolic reactions occur in the cytoplasm. Hence it is called the site of cellular activities.
5. Write any three differences between plant and animal cells.
Answer:
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Large vacuole | Small vacuoles |
| Chloroplast present | Chloroplast absent |
D. Long Answer Questions (5 Marks)
1. Explain the contributions of Schleiden, Schwann and Virchow in Cell Theory.
Answer:
- Schleiden (1838) concluded that all plants are composed of cells.
- Schwann (1839) concluded that all animals are composed of cells.
- Together they proposed Cell Theory.
- The theory failed to explain the origin of new cells.
- Virchow (1855) proposed "Omnis cellula e cellula" meaning all cells arise from pre-existing cells.
- This gave the final form to Cell Theory.
2. Describe the structure of a typical eukaryotic cell.
Answer:
A typical eukaryotic cell consists of:
- Plasma membrane – outer covering.
- Cytoplasm – semi-fluid matrix.
- Nucleus – contains chromosomes and DNA.
- Membrane-bound organelles:
- ER
- Golgi body
- Lysosomes
- Mitochondria
- Vacuoles
- Ribosomes for protein synthesis.
E. Assertion and Reason Questions
1.
Assertion (A): Ribosomes are found in both prokaryotic and eukaryotic cells.
Reason (R): Ribosomes are non-membrane-bound organelles.
Answer: Both A and R are true, and R is the correct explanation.
2.
Assertion (A): Prokaryotic cells lack membrane-bound organelles.
Reason (R): They possess a true nucleus.
Answer: A is true but R is false.
3.
Assertion (A): Cell wall is a unique feature of plant cells.
Reason (R): Animal cells have only plasma membrane.
Answer: Both A and R are true and R is the correct explanation.
4.
Assertion (A): Virchow modified Cell Theory.
Reason (R): He explained the origin of new cells.
Answer: Both A and R are true and R is the correct explanation.
F. Fill in the Blanks
1.
All cells arise from __________ cells.
Answer: pre-existing
2.
The genetic material present in chromosomes is __________.
Answer: DNA
3.
The smallest living cells are __________.
Answer: Mycoplasma
4.
The site of protein synthesis is __________.
Answer: Ribosome
5.
Animal cells possess __________ which helps in cell division.
Answer: Centrosome
6.
Cells with membrane-bound nuclei are called __________.
Answer: Eukaryotic
7.
The semi-fluid matrix inside the cell is called __________.
Answer: Cytoplasm
8.
The outer boundary of animal cells is the __________.
Answer: Plasma membrane
G. True/False Statements
1.
All living organisms are composed of cells.
Answer: True
2.
Virchow proposed that cells arise spontaneously.
Answer: False
3.
Ribosomes are membrane-bound organelles.
Answer: False
4.
Plant cells possess cell wall.
Answer: True
5.
DNA is present inside chromosomes.
Answer: True
6.
Prokaryotic cells contain mitochondria.
Answer: False
H. Case Study Questions
Case Study 1
A student observed onion peel cells and human cheek cells under a microscope. He noticed that onion peel cells possessed an additional outer covering which was absent in cheek cells.
Questions
1. Name the additional covering.
Answer: Cell wall
2. Which type of cell possesses this structure?
Answer: Plant cells
3. Which structure is common in both cells?
Answer: Plasma membrane
4. What is the function of cell wall?
Answer: Provides shape, support and protection.
Case Study 2
A scientist observed a cell containing nucleus, mitochondria, Golgi body and ER.
Questions
1. Is it a prokaryotic or eukaryotic cell?
Answer: Eukaryotic cell
2. Why?
Answer: Presence of membrane-bound organelles.
3. Which organelle is called powerhouse of cell?
Answer: Mitochondria
4. What is the function of Golgi body?
Answer: Packaging and secretion of materials.
I. Match the Columns
Match Column A with Column B
| Column A | Column B |
|---|---|
| 1. Schleiden | a. Animal cells |
| 2. Schwann | b. Cell division |
| 3. Virchow | c. Plant cells |
| 4. Ribosome | d. Protein synthesis |
Answer
1 → c
2 → a
3 → b
4 → d
Match Column A with Column B
| Column A | Column B |
|---|---|
| 1. Mitochondria | a. Cell division |
| 2. Centrosome | b. ATP production |
| 3. DNA | c. Genetic material |
| 4. Cytoplasm | d. Metabolic reactions |
Answer
1 → b
2 → a
3 → c
4 → d
J. CBSE Competency-Based Statement Questions
1. Identify the incorrect statement.
a) Ribosomes are present in all cells.
b) Prokaryotic cells possess mitochondria.
c) DNA is present in chromosomes.
d) Animal cells lack cell wall.
Answer: b) Prokaryotic cells possess mitochondria.
2. Select the correct statements.
- Cell theory was proposed by Schleiden and Schwann.
- Virchow explained origin of new cells.
- Ribosomes are membrane-bound.
- Centrosome helps in cell division.
Options: a) 1 and 2 only b) 1, 2 and 4 only c) 2 and 3 only d) All of these
Answer: b) 1, 2 and 4 only
Important CBSE One-Liners
- Schleiden → Plants are made of cells.
- Schwann → Animals are made of cells.
- Virchow → Cells arise from pre-existing cells.
- DNA → Genetic material.
- Ribosome → Protein factory.
- Mitochondria → Powerhouse of cell.
- Centrosome → Cell division.
- Mycoplasma → Smallest living cell.
- Cytoplasm → Site of metabolic activities.
- Cell wall → Present in plant cells only.
INTERNAL LINKS
• Cell Structure and Cell Organelles Notes • Prokaryotic vs Eukaryotic Cells Explained • Plasma Membrane Structure and Function • Nucleus and Chromosomes NEET Notes • Cell Cycle and Cell Division Notes • Biomolecules Chapter Notes • Transport in Cells NCERT Guide • Complete Class 11 Biology Notes • Most Important Biology MCQs for NEET • NCERT Biology Chapter-wise Revision Notes
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