Cell The Unit of Life- 1
-
Upload
aisharobayda -
Category
Education
-
view
504 -
download
1
Transcript of Cell The Unit of Life- 1
CELL : THE UNIT OF
LIFE PART 1
BY NIHALA…GULF ASIAN ENGLISH SCHOOL..
what is a cell ?
Cell is the basic unit of life.All organisms are composed of cellSome organisms are unicellular .eg: bacteriaAnd while some are multicellular . eg: humanCell is the fundamental structural and functional unit of all living organisms.
History of cell studyRobert hooke-1665Coined 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-1858All cells come from cells.
Theodor Schwann Mattias Schleiden
Rudolf Virchow Robert Brown
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.
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.
Cell Organelle• 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.
Organelles and its functions
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
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
Cell differ greatly is size , shape and activities.Cells may be disc-like ,polygonal,columnar,cuboid,thread-like,or even irregular.Cell shape may vary with the function they performed.
red blood cells (round and biconcave)
white blood cells (amoeboid)
Columnar epithelial cells(long and narrow) Nerve cell
(branched and long)
A tracheid (elongated)