CELL SCIENCE

WHAT IS A CELL?The cell is the basic structural, functional and biological unit of all known living organisms. It is the smallest unit of life that is classified as a living thing and is often called as “ building block of life”

ROBERT HOOKE

He is the first person who identified the cells in 1665

SIZE OF THE CELLSThe smallest cell is 0.1 to 0.5 micrometer in bacteria.

The largest cell measuring 170mm x 130mm, is he ostrich egg.

THE CELL THEORY

The cell theory states that:

All the living things are composed of cellsCells are the basic units of structure and function in living thingsNew cells are produced from existing cells

Schleiden Virchow Schwann

SHAPE OF CELLSSmooth muscle cellOvumEpithelial cellsNerve cellFat cellRBCsSpirogyraSpermAmoebaBacteria

TYPES OF CELLS

Prokaryotic cellsEukaryotic cells

PROKARYOTIC CELLS

Prokaryotic cells are a group of organisms whose cells lack a membrane- bound nucleus

BLUE GREEN ALGAE BACTERIA

EUKARYOTIC CELLS

Eukaryotic cells has well organized nucleus with a nuclear membrane.

Ex: All organisms other than blue green algae and bacteria are eukaryotic cells

PARTS OF A CELLCell membraneCytoplasmOrganellesMitochondriaRibosomesGolgi bodiesNucleusNuclear membraneChromosomesVacuoleChloroplastsPlastids

PLANT CELL