Endomembrane System Class 11 Notes (ER, Golgi, Lysosomes, Vacuoles) | NCERT + NEET PYQ

🧬 Endomembrane System (ER, Golgi, Lysosomes, Vacuoles)

📌 Introduction

In eukaryotic cells, several organelles work together in a coordinated manner forming the Endomembrane System.

• Includes: ER, Golgi apparatus, Lysosomes, Vacuoles
• Not included: Mitochondria, Chloroplast, Peroxisomes

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1️⃣ Endoplasmic Reticulum (ER)

Endoplasmic Reticulum

• RER: Protein synthesis
• SER: Lipid & steroid synthesis, detoxification

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2️⃣ Golgi Apparatus

Golgi Apparatus

• Discovered by Camillo Golgi
• Cis face: Receiving side
• Trans face: Shipping side
• Forms glycoproteins & glycolipids

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3️⃣ Lysosomes

Lysosomes

• Contain hydrolytic enzymes
• Function at acidic pH
• Known as suicidal bags

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4️⃣ Vacuoles

Vacuole

• Membrane = Tonoplast
• Occupies ~90% in plant cells
• Maintains osmotic balance

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📊 Quick Revision Table

Organelle	Function
RER	Protein synthesis
SER	Lipid synthesis
Golgi	Packaging & transport
Lysosome	Digestion
Vacuole	Storage

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📚 NEET PYQ

Q1. Golgi apparatus discovered by?

A) Mendel B) Golgi C) Darwin D) Watson

Answer: B

Q2. Lysosome works best at?

A) Neutral B) Basic C) Acidic D) Alkaline

Answer: C

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📝 Practice MCQs (NEET Level)

Q1. Which organelle is responsible for protein synthesis?

A) SER
B) RER
C) Golgi
D) Lysosome

Answer: B

Q2. Detoxification of drugs occurs in:

A) RER
B) SER
C) Golgi
D) Vacuole

Answer: B

Q3. Which organelle modifies and packages proteins?

A) ER
B) Lysosome
C) Golgi apparatus
D) Vacuole

Answer: C

Q4. Lysosomes are known as:

A) Powerhouse
B) Suicidal bags
C) Brain of cell
D) Storage sacs

Answer: B

Q5. Vacuole membrane is called:

A) Plasmalemma
B) Tonoplast
C) Cristae
D) Matrix

Answer: B

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