Cells are the fundamental units of life, classified into prokaryotic and eukaryotic types, and were first identified by Robert Hooke in 1665. The cell theory states that all living things are composed of cells, which are the basic units of structure and function, and that new cells arise from existing cells. Cells come in various shapes and sizes, with examples including smooth muscle cells, nerve cells, and bacteria.

1. CELL SCIENCE

2. 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”

3. ROBERT HOOKE
He is the
first person
who
identified
the cells in
1665

4. SIZE OF THE CELLS
The smallest cell is 0.1 to 0.5 micrometer in
bacteria.
The largest cell measuring 170mm x 130mm, is he
ostrich egg.

5. THE CELL THEORY
The cell theory states that:
All the living things are composed of cells
Cells are the basic units of structure and
function in living things
New cells are produced from existing cells
Schleiden Virchow Schwann

6. SHAPE OF CELLS
Smooth muscle cell
Ovum
Epithelial cells
Nerve cell
Fat cell
RBCs
Spirogyra
Sperm
Amoeba
Bacteria

7. TYPES OF CELLS
Prokaryotic cells
Eukaryotic cells

8. PROKARYOTIC CELLS
Prokaryotic cells are a group of organisms whose
cells lack a membrane- bound nucleus
BLUE GREEN ALGAE BACTERIA

10. 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

12. PARTS OF A CELL
Cell membrane
Cytoplasm
Organelles
Mitochondria
Ribosomes
Golgi bodies
Nucleus
Nuclear membrane
Chromosomes
Vacuole
Chloroplasts

13. PLANT CELL