Difference Between Prokaryotic and Eukaryotic Cells: NEET Notes for Beginners
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Comparison of Prokaryotic and Eukaryotic Cells with key structures explained for NEET Biology preparation. |
- Dr.Sanjaykumar Pawar
Bacterial Cell Structures (Continuation)
- Some bacterial membrane extensions help in:
- Cell division (formation of daughter cells)
- DNA replication and distribution
- Respiration
- Secretion processes
- Increasing surface area of plasma membrane
- Increasing enzyme content
Chromatophores (in some bacteria)
- Found in cyanobacteria
- They are membrane extensions inside cytoplasm
- Contain photosynthetic pigments
- Help in photosynthesis
Movement in Bacteria
- Some bacteria are motile (can move)
- Some are non-motile (cannot move)
Flagella
- Long, thin, thread-like structures outside cell wall
- Help in movement (motility)
- Present only in motile bacteria
Structure of flagellum
-
Made of 3 parts:
- Filament → longest outer part
- Hook → connects filament to basal body
- Basal body → anchors flagellum in cell
-
Number and arrangement of flagella vary in bacteria
Pili and Fimbriae
- Both are surface structures of bacteria
- Do NOT help in movement
Pili
- Long, tubular protein structures
- Help in attachment and sometimes DNA transfer
Fimbriae
- Short, hair-like structures
- Help bacteria attach to surfaces like:
- Rocks in streams
- Host tissues
Ribosomes in Prokaryotes
- Present in cytoplasm, often attached to plasma membrane
- Small size: 15 nm × 20 nm
- Made of two subunits:
- 50S + 30S = 70S ribosome
Function
- Site of protein synthesis
Polyribosomes (Polysomes)
- Many ribosomes attach to one mRNA
- Form a chain called polysome
- Helps in making many protein copies quickly
Inclusion Bodies
- Storage granules in prokaryotic cells
- Not surrounded by membrane
- Free in cytoplasm
Examples
- Phosphate granules
- Cyanophycean granules
- Glycogen granules
Gas Vacuoles
- Found in:
- Blue-green algae (cyanobacteria)
- Purple and green photosynthetic bacteria
- Help in buoyancy (floating in water)
Eukaryotic Cells
Basic Features
- Found in:
- Protists
- Plants
- Animals
- Fungi
Main Characteristics
- Have membrane-bound organelles
- Cytoplasm is compartmentalized
- Have a true nucleus with nuclear envelope
- DNA is organized into chromosomes
- Have complex cytoskeleton and movement structures
Plant vs Animal Cells
Plant cells have:
- Cell wall
- Plastids (like chloroplasts)
- Large central vacuole
Animal cells have:
- Centrioles
- No cell wall
- No plastids
CELL
│
├── PROKARYOTIC CELL
│ │
│ ├── Cell Membrane Extensions
│ │ ├── DNA replication
│ │ ├── Distribution to daughter cells
│ │ ├── Respiration
│ │ ├── Secretion
│ │ ├── Increase surface area
│ │ └── Increase enzyme content
│ │
│ ├── Chromatophores
│ │ ├── Found in Cyanobacteria
│ │ ├── Membranous extensions
│ │ └── Contain pigments
│ │
│ ├── Surface Structures
│ │ │
│ │ ├── Flagella (Motility)
│ │ │ ├── Filament
│ │ │ ├── Hook
│ │ │ └── Basal Body
│ │ │
│ │ ├── Pili
│ │ │ ├── Tubular structures
│ │ │ └── Attachment / DNA transfer
│ │ │
│ │ └── Fimbriae
│ │ ├── Short bristle-like fibres
│ │ └── Attachment to surfaces & host tissues
│ │
│ ├── Ribosomes
│ │ ├── 70S Ribosome
│ │ │ ├── 50S Subunit
│ │ │ └── 30S Subunit
│ │ ├── Protein synthesis
│ │ └── Polysomes
│ │ └── Many ribosomes on one mRNA
│ │
│ └── Inclusion Bodies
│ ├── Non-membrane bound
│ ├── Storage materials
│ ├── Phosphate granules
│ ├── Cyanophycean granules
│ ├── Glycogen granules
│ └── Gas vacuoles
│ ├── Cyanobacteria
│ └── Purple & Green bacteria
│
└── EUKARYOTIC CELL
│
├── Found In
│ ├── Protists
│ ├── Plants
│ ├── Animals
│ └── Fungi
│
├── Features
│ ├── Membrane-bound organelles
│ ├── Compartmentalized cytoplasm
│ ├── True nucleus
│ ├── Nuclear envelope
│ ├── Chromosomes
│ └── Cytoskeleton
│
├── Plant Cell
│ ├── Cell wall
│ ├── Plastids
│ └── Large central vacuole
│
└── Animal Cell
└── Centrioles
1. MCQs (1 Mark Each)
Q1. The ribosome present in prokaryotic cells is:
a) 80S
b) 70S
c) 60S
d) 90S
Answer: b) 70S
Q2. Which structure helps bacteria in motility?
a) Pili
b) Fimbriae
c) Flagella
d) Ribosome
Answer: c) Flagella
Q3. Chromatophores are found in:
a) Animal cells b) Fungi c) Cyanobacteria d) Plant cells
Answer: c) Cyanobacteria
Q4. Gas vacuoles occur in:
a) Fungi b) Cyanobacteria c) Animals d) Protozoa
Answer: b) Cyanobacteria
Q5. Which organelle is absent in prokaryotes?
a) Ribosome b) Plasma membrane c) Nucleus d) Cytoplasm
Answer: c) Nucleus
Q6. Fimbriae help in:
a) Respiration b) Motility c) Attachment d) Digestion
Answer: c) Attachment
Q7. Reserve food materials in bacteria are stored as:
a) Lysosomes b) Inclusion bodies c) Vacuoles d) Plastids
Answer: b) Inclusion bodies
Q8. Plant cells possess:
a) Centrioles b) Plastids c) Flagella d) Pili
Answer: b) Plastids
2. Very Short Answer Questions (1 Mark)
Q1. What is a polysome?
Answer: A group of ribosomes attached to a single mRNA molecule.
Q2. Name the three parts of bacterial flagellum.
Answer: Filament, Hook and Basal Body.
Q3. What is the function of ribosomes?
Answer: Protein synthesis.
Q4. What are chromatophores?
Answer: Pigment-containing membranous structures found in cyanobacteria.
Q5. Which cell has a true nucleus?
Answer: Eukaryotic cell.
3. Short Answer Questions (2–3 Marks)
Q1. Differentiate between pili and fimbriae.
| Pili | Fimbriae |
|---|---|
| Longer structures | Short bristle-like structures |
| Help in attachment and DNA transfer | Help only in attachment |
Q2. Write any three characteristics of prokaryotic cells.
Answer:
- Lack true nucleus.
- Lack membrane-bound organelles.
- Possess 70S ribosomes.
Q3. What are inclusion bodies? Give examples.
Answer: Inclusion bodies are non-membrane-bound storage structures found in prokaryotes.
Examples:
- Glycogen granules
- Phosphate granules
- Cyanophycean granules
Q4. Mention any three differences between plant and animal cells.
| Plant Cell | Animal Cell |
|---|---|
| Cell wall present | Cell wall absent |
| Plastids present | Plastids absent |
| Large central vacuole | Small vacuoles |
4. Long Answer Questions (5 Marks)
Q1. Describe the structure and function of bacterial flagellum.
Answer:
The bacterial flagellum is a locomotory organ used for movement.
It consists of three parts:
-
Filament
- Longest part.
- Extends outside the cell.
-
Hook
- Connects filament to basal body.
-
Basal Body
- Anchors the flagellum in the cell wall.
Functions:
- Helps in movement.
- Enables bacteria to move toward favorable conditions.
Q2. Explain the major features of eukaryotic cells.
Answer:
- Possess a true nucleus enclosed by nuclear membrane.
- Have membrane-bound organelles.
- Cytoplasm is compartmentalized.
- DNA organized into chromosomes.
- Have cytoskeleton and locomotory structures.
- Found in plants, animals, fungi and protists.
5. Assertion and Reason Questions
Q1.
Assertion (A): Ribosomes are the sites of protein synthesis.
Reason (R): Ribosomes are made up of 50S and 30S subunits in prokaryotes.
Answer: Both A and R are true, and R correctly explains A.
Q2.
Assertion (A): Fimbriae help in bacterial motility.
Reason (R): Fimbriae are short bristle-like structures.
Answer: Assertion is false but Reason is true.
Q3.
Assertion (A): Eukaryotic cells have membrane-bound organelles.
Reason (R): Their cytoplasm is compartmentalized.
Answer: Both A and R are true, and R correctly explains A.
6. Fill in the Blanks
-
Ribosomes in prokaryotes are ________ type. Answer: 70S
-
The longest part of flagellum is the ________. Answer: Filament
-
________ are pigment-containing membranous structures. Answer: Chromatophores
-
Storage granules in bacteria are called ________. Answer: Inclusion bodies
-
Animal cells possess ________. Answer: Centrioles
-
Plant cells contain ________. Answer: Plastids
-
A true nucleus is present in ________ cells. Answer: Eukaryotic
7. Statement-Based Questions
Q1. Read the statements:
I. Prokaryotes possess membrane-bound organelles.
II. Prokaryotes contain 70S ribosomes.
Choose the correct option:
a) Both correct
b) Both incorrect
c) I correct, II incorrect
d) I incorrect, II correct
Answer: d) I incorrect, II correct
Q2.
I. Plant cells have plastids. II. Animal cells have centrioles.
a) Both true b) Both false c) Only I true d) Only II true
Answer: a) Both true
8. Match the Columns
Q1.
| Column A | Column B |
|---|---|
| A. Flagella | 1. Storage |
| B. Ribosomes | 2. Protein synthesis |
| C. Inclusion bodies | 3. Motility |
| D. Fimbriae | 4. Attachment |
Answer:
A → 3
B → 2
C → 1
D → 4
Q2.
| Column A | Column B |
|---|---|
| A. Chromatophore | 1. Plant cell |
| B. Plastid | 2. Cyanobacteria |
| C. Centriole | 3. Animal cell |
| D. Gas vacuole | 4. Photosynthetic bacteria |
Answer:
A → 2
B → 1
C → 3
D → 4
9. Case Study Questions (CBSE Pattern)
Case Study 1
A student observed a bacterial cell under a microscope. He found a thread-like structure helping in movement and small granules storing reserve food material.
Questions:
Q1. Name the locomotory structure.
Answer: Flagellum
Q2. Name the storage granules.
Answer: Inclusion bodies
Q3. Which type of ribosome is present in this cell?
Answer: 70S ribosome
Q4. Is it a prokaryotic or eukaryotic cell?
Answer: Prokaryotic cell
Case Study 2
A scientist studied a cell possessing plastids, a cell wall and a large central vacuole.
Questions:
Q1. Identify the cell.
Answer: Plant cell
Q2. Name the organelle responsible for photosynthesis.
Answer: Chloroplast
Q3. Is centriole present in this cell?
Answer: No
Q4. Which category of cell is it?
Answer: Eukaryotic cell
Important CBSE Exam Questions
- Draw and label bacterial flagellum.
- Explain 70S ribosome structure.
- Differentiate between prokaryotic and eukaryotic cells.
- Explain inclusion bodies with examples.
- Compare plant and animal cells.
- Describe chromatophores and gas vacuoles.
- Explain the functions of pili and fimbriae.
- State the characteristics of eukaryotic cells.
Internal Links
Link this article to:
Cell: The Unit of Life Notes
Biomolecules Complete NEET Notes
Cell Membrane Structure and Functions
Nucleus: Structure and Functions
Ribosomes and Protein Synthesis
Plant Cell vs Animal Cell Differences
NCERT Class 11 Biology Chapter 8 Summary
Cell Organelles Explained for NEET
Photosynthesis in Cyanobacteria
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