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AAT Bioquest

What are the differences between prokaryotic and eukaryotic cells?

Posted September 17, 2022


Answer

There are several significant differences between prokaryotic and eukaryotic cells, from structural variations to molecular variations. The most important difference between the two is the presence of a membrane-bound nucleus in eukaryotic cells, whereas prokaryotic cells have a nucleoid region instead of a true nucleus.

Basis of differentiationProkaryotic cells Eukaryotic cells
DefinitionUnicellular organisms that lack a true membrane-bound nucleus Cells that contain a true nucleus enclosed within the nuclear membrane
True membrane bound nucleusAbsent - DNA is bundled together in the nucleoid region instead of within a membrane-bound nucleusPresent – all genetic information is stored in this structure
Cell structureUnicellular (some cyanobacteria may be multicellular)Mostly multicellular – very few unicellular
SizeSmall, measuring around 0.1-5 μm in diameter.    Large, measuring around 10-100 μm 
Complexity of cellsSimple cellsMore complex cells
CytoskeletonMay be absent Present
Membrane bound organellesAbsent Present
MitochondriaAbsent Present
Endoplasmic reticulumAbsent Present
RibosomesPresent – smaller in size Present - larger in size
Golgi complexAbsent  Present
VesiclesPresent Present
MicrotubulesAbsent or rare Present
Lysosomes and peroxisomesAbsent Present
FlagellaSmaller, narrower, and single-stranded – perform rotary motionsLarger, thicker, and eleven-stranded – perform lashing or undulating movements
Number of chromosomesA single circular chromosomeMultiple linear chromosomes
DNA structure and locationSingle loop of stable chromosomal DNA located in an area named the nucleoidMultiple molecules of double-stranded linear DNA found on tightly bound and organized chromosomes – located in a true nucleus
DNA replicationOccurs through a single origin of replication – the prokaryotic organism duplicates its entire genome and the second copy is passed on to a daughter cellOccurs through multiple replication origins – genome typically duplicates prior to cell division
Coupling of transcription and translation

Transcription and translation are coupled – both processes can occur simultaneously because prokaryotic DNA can interact with the cytoplasm

Transcription and translation are not coupled - transcription occurs in the nucleus and translation occurs in the cytoplasm

Number of gene copiesMost are haploid - contain only one copy of each gene Most are diploid - contain two copies of each gene
Chloroplasts Present (in plants)Absent - chlorophyll scattered in the cytoplasm
Genetic recombinationOccurs through the unilateral transfer of DNA Occurs during the crossing over event of meiosis, when genetic material is exchanged by homologous chromosomes 
MitochondriaAbsentPresent
ExamplesBacteria and archaeaAnimals, plants, fungi, algae and protozoans 

 

Additional resources

The origin of eukaryotes: the difference between prokaryotic and eukaryotic cells

Cell Navigator® Lysosome Staining Kit *Blue Fluorescence*

Cell Structures and Organelles