Eukaryotic Cells Class 11 Notes (NCERT + Cell Membrane + Diagram + MCQ + NEET PYQ)

🧬 Eukaryotic Cells – Introduction & Cell Membrane

📌 Overview of Eukaryotic Cells

Eukaryotic cells are advanced cells with a well-defined nucleus enclosed by a nuclear membrane. They contain complex membrane-bound organelles that perform specialized functions.

🔹 Examples of Eukaryotic Cells

• Protists
• Plants
• Animals
• Fungi

Examples of Eukaryotic Cells

Did you know? Fungal cell walls are made of chitin, while plant cell walls are made of cellulose.

Important Comparison:
Animal cells lack cell wall and plastids, but contain centrioles. Plant cells have cell wall and plastids but usually lack centrioles.

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🧫 Cell Membrane (Plasma Membrane)

The plasma membrane is composed of lipids and proteins and controls the movement of substances in and out of the cell.

Fluid Mosaic Model

🔬 Chemical Composition

• Lipids: Phospholipid bilayer
• Proteins:
  • Integral proteins
  • Peripheral proteins

🌊 Fluid Mosaic Model (Most Important for NEET)

Proposed by Singer and Nicolson (1972).

• Concept: Lateral movement of proteins
• Fluidity: Important for cell growth and division

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⚙️ Functions of Plasma Membrane

• Selective permeability
• Transport:
  • Passive (diffusion, osmosis)
  • Active (ATP required)

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📚 NEET Previous Year Questions (PYQ)

Q1. Fluid Mosaic Model proposed by?

A) Watson & Crick
B) Singer & Nicolson
C) Mendel
D) Darwin

Answer: B

Q2. Fungal cell wall composition?

A) Cellulose
B) Chitin
C) Protein
D) Lipid

Answer: B

Q3. Plasma membrane fluidity depends on?

A) Lipids
B) Proteins
C) Carbohydrates
D) DNA

Answer: A

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📝 Practice MCQs

Q1. Fluid Mosaic Model allows:

A) Vertical movement
B) Lateral movement
C) Fixed position
D) Outer layer only

Answer: B

Q2. Cell wall of fungi:

A) Cellulose
B) Chitin
C) Protein
D) Peptidoglycan

Answer: B

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