Question

What is Difference between prokaryotic and eukaryotic cells

Answer 1

Differences between Prokaryotic and Eukaryotic cells

Depending on the internal structure of cell, organisms are divided into two types i.e. prokaryotic and Eukaryotic.Prokaryotic organism are those which lacks true nucleus and membrane bound cell organelles. Eukaryotic organisms are those organisms which have true nucleus with nuclear and nucleolus and also contain all membrane bound cell organelles.

Differences between Prokaryotic and Eukaryotic cells

FeaturesProkaryoticEukaryoticSizeSize of cell is 1-2µm by 1-4µm or less.Greater than 5 µm in diameter.
Cell typeMostly unicellular(some cyanobacteria may be multicellular).Mostly multicellular.NucleusTrue nucleus is absent.

Nucleus lack nuclear membrane and nucleolus. Such nucleus is called nucleoid.Nuclear membrane and nucleolus are present.ChromosomeUsually single circular without histones.Multiple linear with histones.GenesExpressed in groups called operons.Expressedindividually.
ZygoteMerozygotic (partially diploid).Diploid.Cell divisionBinary fission of buddingInvolves mitosis.Sexual reproductionNo meiosis. Transfer of DNA only.Involves meiosis.Permeability of nuclear membraneAbsent.Selective.Cytoplasmic streamingAbsentPresentCytoskeletonAbsentPresentPinocytosisAbsentPresentGas vacuolesCan be presentAbsentMesosomePresent. Performs the function of Golgi bodies and mitochondria and also help in the separation of chromosome during cell division.AbsentRibosomeSmaller size 70S, distributed in the cytoplasm.Larger size 80s, found on membranes as in endoplasmic reticulum; 70s present in organelles such as chloroplast and mitochondria.MitochondriaAbsentPresentChloroplastAbsentPresentEndoplasmic ReticulumAbsentPresentGolgi structureAbsentPresentMembrane bound vacuolesAbsentPresentLysosomes and peroxisomesAbsentPresentMicrotubulesAbsent or rarePresentFlagellaSimple structure composed of protein, flagellin.Complex with 9+2 structure of tubulin and other protein.Plasma membraneGenerally lack sterol and no carbohydrate.

Contain part of respiration and in some photosynthetic machinery.

Sterol and carbohydrate is present that serve as receptors.
Do not carry out respiration and photosynthesis.GlycocalyxPresent as a capsule or slime layer.Present in some cells that lack cell wall.Cell wallUsually present. Chemically complex (typical bacterial cell wall includes peptidoglycan).When present, chemically simple (includes cellulose and chitin).Extrachromosomal plasmidPresent. Nonessential prokaryotic genes are encoded on extra chromosomal plasmid.AbsentTranscription and translationOccur simultaneously
.Transcription occurs in nucleus and then translation occurs in cytoplasm.RespirationMany strict anaerobes.
All aerobic, but some facultative anaerobes by secondary modification
.Photosynthetic enzymesBound to plasma membrane as composite chromatophores.Enzymes packed in plastids bound by membrane.
Nitrogen fixationSome possess this ability.None possess this ability.Metabolic mechanismWide variationGlycolysis, electron transport chain, Krebs cycle.Duration of cell cycleShort, takes 20-60 minutes to complete.
Long, takes 12-24 hours to complete.DNA base ratio as mol% of Guanine+ Cytosine (G+C %)28-73About 40



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Answer 2

(1) In Prokaryotic nucleus is not present and any other membrane bound organelles bt eukaryotic cell contain membrane bound organelles.
(2) There is RNA or DNA in cytoplasm where as DNA in nucleus and RNA travel in or out of nucleus.
(3)Most prokaryotes contain single copy of genes where as most eukaryotes contain two copies of each genes.