This document compares and contrasts prokaryotic and eukaryotic cells. It notes that prokaryotes like bacteria and archaea lack complex internal structures like membrane-bound organelles, while eukaryotic cells have structures like the nucleus enclosed in membranes. A key difference is that prokaryotes have 70S ribosomes while eukaryotes have 80S ribosomes in the cytoplasm and 70S in organelles. The endosymbiotic theory proposes that mitochondria and chloroplasts were originally prokaryotic cells that lived symbiotically inside eukaryotic cells and became permanent organelles.

1. ANKIT ALANKAR
CHANAKYA EDUCATION HUB
Prokaryotes & Eukaryotes

2. MEANS
 Prokaryotes
Pro :- before
Karyon :- kernal or nucleus
Eukaryotes
Eu :- new
karyon :- kernal or nucleus

3. PROKARYOTES
 Prokaryotes consist of eubacteria & archaea.
Eubactria :- the term refer specifically to bactria .
Archaea :- also term as archaebacteria or archaeobactria
Prokaryotic cell have a simpler internal structure then eukaryotic
cells.
Prokaryotes can be distinguished from eukaryotes in terms of their
cell structure & molecular make up.
Most prokaryotes lack extensive , complex , internal membrane
system.
Although many structure are common to both cell types , some
are unique to prokaryotes .

4. MAJOR CHARACTERISTICS OF PROKARYOTES &
EUKARYOTES
 Feature of prokaryotic organisms
Ture membrane bound nucleus - absent
DNA complexed with histone - absent
Number of chromosomes - one(mostly)
Mitosis & Meiosis - absent
Ribosome - 70S
( S means sendimation rate)
Genetic recombination -Partial (unidirectional transfer of
DNA)
Sterol in plasma membrane - absent (except Mycoplasma )
Unit membrane bound organelles – absent
Cell Wall - present in most of prokaryotic cells. In eubactria
,it is made up of Peptidoglycan.

5. MAJOR CHARACTERISTICS OF PROKARYOTES &
EUKARYOTES
 Feature of eukaryotic organisms
Ture membrane bound nucleus - present
DNA complexed with histone - present
Number of chromosomes - more then one
Mitosis & Meiosis - present
Ribosome - 80S (in cytosol), 70S (in
organelles)
(cytoplasm lack cell organelles that’s called a Cytosol)
Genetic recombination - By crossing over during meiosis
Sterol in plasma membrane present
Unit membrane bound organelles – present
Cell Wall -made up of cellulose in plant & chitin in fungi . Absent
in animal cells.

6. SIMILARITIES BETWEEN PROKARYOTES CELL &
EUKARYOTIC ORGANELLES
Prokaryotic cell Eukaryotic cell
Name of DNA ds circular ds circular
Histone protein absent absent
Ribosomes types 70S 70S
Growth Binary fission Binary fission

7. THE ENDOSYMBIOTIC THRORY
 Prokaryotic cells show similarities with eukaryotic
organelles like mitochondria & chloroplast .
The Endosymbiotic theory (Margulis ,1993) proposes
that the mitochondria & chloroplast of eukaryotic cells
originated as symbiotic prokaryotic cells.
The presence of circular , covalently closed DNA & 70S
ribosomes in mitochondria & chloroplast support this
theory.