1. CELL : THE UNIT OF
LIFE PART 1
BY NIHALA…
GULF ASIAN ENGLISH SCHOOL..

2. what is a cell ?
Cell is the basic unit of life.
All organisms are composed of cell
Some organisms are unicellular .eg: bacteria
And while some are multicellular . eg: human
Cell is the fundamental structural and
functional unit of all living organisms.

3. History of cell study
Robert hooke-1665
Coined the word “cell”.
Looked at cork cells.
Robert brown-1831
Discovered the “nucleus”.
Theodor Schwann- 1838
Cells are unit of biological structures.
Mattias Schleiden-1850
Cell are the fundamental basis of life.
Virchow-1858
All cells come from cells.

4. Theodor Schwann
Mattias Schleiden
Rudolf Virchow
Robert Brown

5. 1. Every organisms is made up of at least one cell.
2. Cells are the basic structural and functional
unit of multicellular organisms.
3. All cells arise from preexisting cells.

6. Cell Overview
 There are two types of cells, eukaryotes, which
contain a nucleus, and prokaryotes, which do not.
 Prokaryotic cells are usually single celled
organisms, while eukaryotic cells can be either
single-celled or part of multicellular organisms.

7. Cell Organelle
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Besides the nucleus, the eukaryotic cells have other
membrane bound distinct structures called
organelles.
An organelle is a specialized subunit within a cell
that has a specific function, and it is usually
separately enclosed within its own lipid bilayer.

9. Organelles and its functions
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Cell wall
Support(grow tall)
Protection
Cell membrane
Barrier between cell and its membrane
Maintains homeostasis
Nucleus
Control cell activities
Nuclear membrane
Controls movements of materials in and out of nucleus
Endoplasmic reticulum
Carries materials through cell

10.  Vacuoles
 Store food ,water , waste(plants need to store large
amounts of food)
 Lysosome
 Breaks down larger food molecules into smaller molecules
 Digests old cell parts
 Chloroplasts
 Uses energy from sun to make food for plants
(photosynthesis)
 Ribosome
 Produces proteins
 Mitochondrion
 Breaks down sugar molecules into energy

11.  Cell differ greatly is size , shape and activities.
Cells may be disc-like ,polygonal,columnar,cuboid,threadlike,or even irregular.
Cell shape may vary with the function they performed.
red blood cells
(round and biconcave)
white blood cells
(amoeboid)

12. Columnar epithelial cells
(long and narrow)
Nerve cell
(branched and long)
A tracheid
(elongated)