comparison of euk and prok

7/31/2019 Comparison of Euk and Prok

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A Comparison of Cells

ProkaryoticCells

Eukaryotic Cellsanimal plant

Cell Membrane

Cell Wall

Nucleus

Chromosomes

Ribosomes

Endoplasmic Reticulum

Golgi Apparatus

Lysosomes

Vacuoles

Mitochondria

Chloroplasts

Cytoskeleton


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A Comparison of Cells

ProkaryoticCells

Eukaryotic Cellsanimal plant

Cell Membrane Yes Yes yes

Cell Wall Yes No yes

Nucleus No Yes yes

ChromosomesYes (onecircularstrand)

Yes (many) Yes (many)

Ribosomes Yes (small) Yes (large) yes

Endoplasmic Reticulum no Yes yes

Golgi Apparatus no Yes yesLysosomes no Yes no

Vacuoles no Yes (small or none) yes

Mitochondria no Yes yes

Chloroplasts no No yes

Cytoskeleton no yes yes


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Prokaryotic and

Eukaryotic Cells Cellular Organization Prokaryotic cells have a simple structural

organization (no membrane-bound nucleus and

no membrane-bound organelles) Eukaryotic cells exhibit compartmentalization

(presence of membrane-bound nucleus andorganelles)

Prokaryotic cells can divide into twoindependent cells in as little as 15 minutes ascompared with an 18-24 hr dividing time foreukaryotes.


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Prokaryotic Cell

Organization Represented by cyanobacteria Bounded by a plasma membrane but

has no other separate membrane-bound organelles.

Do not possess mitochondria or

chloroplasts Usually possess a cell wall which

contains muramic acid


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Ribosomes are smaller than theribosomes in eukaryotes

Unable to take in materials unlessthey are soluble


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Gene Structure and

Organization Eukaryotic Genes DNA is not separated from the cytoplasm by a

nuclear envelope

DNA does not exists in multiple distinctchromosomes but in a single thread.

Prokaryotic chromosomes exist as a covalentlyclosed circular DNA structure completelylacking histones

Distribution of DNA to daughter cells is verysimple and doesnt require the elaboratemitotic process of the eukaryotic cell.


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Chemical Composition Prokaryotic cells do not have thecomplex lipids (sphingolipids,cerebrosides) found in eukaryotes

Prokaryotic cell walls contain muramicacid while eukaryotic cell walls do not

Eukaryotic membranes routinely

contain cholesterol (and sterol) whileno prokaryotic organisms cansynthesize cholesterol.


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Cellular Evolution Current evidenceindicates that eukaryotes

evolved from prokaryotesbetween 1 and 1.5 billionyears ago

Two theories:1. Infolding theory2. Endosymbiotic theory


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Infolding Theory The infolding of theprokaryotic plasma

membrane gave rise toeukaryotic organelles.

infolding organelle


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Endosymbiotic Theory Endosymbiosis refers to one species livingwithin another(the host) Movement of smaller photosynthetic &

heterotrophicprokaryotes into larger

prokaryotic host cells Formed cell organelles

chloroplast

mitochondria


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Endosymbiotic Theory

comparison of euk and prok

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