Cell Organelles & Their Functions – CHEMASH Biology

Cell organelles are specialized structures present inside a cell that perform specific functions. They help the cell survive, grow, and reproduce. This topic is extremely important for Class 9, Class 11, NEET 2026, and other competitive exams.

Before reading this, revise Cell: The Unit of Life.

Nucleus
Mitochondria
Ribosomes
Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Plastids
Vacuole
MCQs
FAQs

1. Nucleus – Control Center

The nucleus is a membrane-bound organelle that controls all cellular activities. It contains genetic material (DNA) arranged in chromosomes.

Nuclear Membrane: Double-layered membrane with pores.
Nucleoplasm: Fluid inside nucleus.
Nucleolus: Produces ribosomes.
Chromatin: DNA + Protein material.

Function:

Controls cell metabolism
Stores hereditary information
Regulates cell division

Exam Tip (NEET): Prokaryotes lack a true nucleus.

2. Mitochondria – Powerhouse of the Cell

Mitochondria produce energy in the form of ATP through cellular respiration. They are called semi-autonomous organelles because they contain their own DNA and ribosomes.
Outer Membrane
Inner Membrane (Cristae)
Matrix
Function:
ATP production
Regulates cell death (apoptosis)
Controls metabolic activity
Important: High in muscle cells due to high energy demand.ns.

3. Ribosomes – Protein Factories

Ribosomes synthesize proteins. They can be free or attached to ER.

4. Endoplasmic Reticulum (ER)

Rough ER – Has ribosomes, makes proteins
Smooth ER – Makes lipids

5. Golgi Apparatus

Discovered by Camillo Golgi. It modifies, packages and transports proteins received from ER.

Helps in cell wall formation (plants)

Forms secretory vesicles

6. Lysosomes – Suicidal Bags

Lysosomes contain hydrolytic enzymes that digest waste materials, damaged organelles, and foreign particles.

Cause autolysis if cell is damaged

Perform intracellular digestion

7. Plastids (Plant Cells)

Chloroplast – Photosynthesis
Chromoplast – Color
Leucoplast – Storage

8. Vacuole

Stores water and maintains turgor pressure.

MCQs (Exam 2026)

1. Powerhouse of the cell?
Answer: Mitochondria

2. Protein synthesis occurs in?
Answer: Ribosomes

3. Suicidal bags of the cell?
Answer: Lysosomes

FAQs

Q. Which organelle has its own DNA?
A. Mitochondria.

Q. Are ribosomes membrane-bound?
A. No.

For official reference visit NCERT Biology.

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Cell Organelles