Anatomy of cell
On the basis of the absence of well-defined nucleus, living organisms were earlier classified into two groups by molecular biologist viz.
- Prokaryotes: Cells not having well defined nucleus as in bacteria and blue green algae.
- Eukaryotes: Included remaining type of organisms having well-organized nucleus.
Differences Between Prokaryotic and Eukaryotic Cells
|
Prokaryotic Cells |
Eukaryotic cells |
|
small cells (< 5 mm) |
larger cells (> 10 mm) |
|
always unicellular |
often multicellular |
|
no nucleus or any membrane-bound organelles, such as mitochondria |
always have nucleus and other membrane-bound organelles |
|
DNA is circular, without proteins |
DNA is linear and associated with proteins to form chromatin |
|
ribosomes are small (70S) |
ribosomes are large (80S) |
|
no cytoskeleton |
always has a cytoskeleton |
|
motility by rigid rotating flagellum made of flagellin |
motility by flexible waving undulipodium, made of tubulin |
|
cell division is by binary fission |
cell division is by mitosis or meiosis |
|
reproduction is always asexual |
reproduction is asexual or sexual |
|
huge variety of metabolic pathways |
common metabolic pathways |
