Cell the unit of life 70 MCQ/neet 2026 🔥/ncert line by line MCQ practice 🔥/score booster series 🔥🤯

Описание: “Cell: The Unit of Life” (Class 11 NCERT – NEET level):

Cell – The Unit of Life

The cell is the basic structural and functional unit of life. All living organisms are made up of one or more cells. The branch of biology that studies cells is called Cytology.

Discovery of Cell

Robert Hooke (1665) discovered cells in a thin slice of cork and coined the term cell.

Leeuwenhoek observed living cells under a microscope.

Robert Brown (1831) discovered the nucleus.

Cell Theory

Proposed by Schleiden and Schwann (1838-39):

All living organisms are composed of cells.

Cell is the basic unit of life.

Later, Rudolf Virchow (1855) added: 3. All cells arise from pre-existing cells.

Types of Cells

1. Prokaryotic Cell

No true nucleus (genetic material is naked).

No membrane-bound organelles.

Example: Bacteria, Cyanobacteria.

Small in size (1–10 µm).

2. Eukaryotic Cell

True nucleus present.

Membrane-bound organelles present.

Example: Plant and Animal cells.

Larger in size (5–100 µm).

Structure of a Cell

1. Plasma Membrane

Outer covering of the cell.

Made of lipid bilayer (Fluid Mosaic Model – Singer & Nicolson).

Selectively permeable.

2. Cell Wall (Plants only)

Made of cellulose.

Provides shape and protection.

3. Cytoplasm

Jelly-like substance.

Contains organelles.

4. Nucleus

Control center of the cell.

Contains DNA.

Surrounded by nuclear membrane.

Cell Organelles and Their Functions

Mitochondria – Powerhouse of the cell (ATP production).

Ribosomes – Protein synthesis.

Endoplasmic Reticulum (ER)

RER – Protein synthesis

SER – Lipid synthesis

Golgi Apparatus – Packaging and secretion.

Lysosomes – Suicidal bags (intracellular digestion).

Plastids (Plants only)

Chloroplast – Photosynthesis

Chromoplast – Pigments

Leucoplast – Storage

Vacuole – Storage (large in plant cells).

Important NEET Points

Mitochondria and chloroplast have their own DNA.

Ribosomes are non-membranous.

Cell membrane follows Fluid Mosaic Model.

Prokaryotes lack membrane-bound organelles.

Plant cells have cell wall and large central vacuole.