Last updated on May 16th, 2021
All living cells can be classified as either prokaryotic or eukaryotic. Prokaryotic cells lack a nucleus and other membrane-enclosed structures, whereas eukaryotic cells have such structures.
All prokaryotes are single-celled organisms and all are bacteria. Eukaryotes include all plants, animals, fungi, and protists (such as malaria parasites).
| Features | Procaryotic cells | Eucaryotic cells |
| Size | 1-2 by 1-4 micrometer or less | Greater than 5 micrometer in width or diameter |
| Genetic system | ||
| Location | Nucleoid, chromatin body or nuclear material | Nucleus, mitochondria, chloroplasts |
| Structure of nucleus | Not bounded by nuclear membrane; one circular chromosome Chromosome does not contain histones; no mitotic division Nucleolus absent; functionally related genes may be clustered. | Bounded by nuclear membrane; more than one chromosome Chromosomes have histones; mitotic nuclear divisionNucelolus present; functionally related genes not clustered |
| Sexuality | Zygote nature is merozygotic (partial diploid) | Zygote is diploid |
| Cytoplasmic nature and Structures | ||
| Cytoplasmic streaming | Absent | Present |
| Pinocytosis | Absent | Present |
| Gas vacuoles | Can be present | Absent |
| Mesosome | Present | Absent |
| Ribosomes | 70S, distributed in the cytoplasm. | 80S arrayed on membranes as in endoplasmic reticulum; 70S in mitochondria and chloroplasts |
| Mitochondria | Absent | Present |
| Chloroplasts | Absent | May be present |
| Golgi structures | Absent | Present |
| Endoplasmic reticulum | Absent | Present |
| Membrane-bound (true) vacuoles | Absent | Present |
| Outer Cell Structure | ||
| Cytoplasmic membranes | Generally do not contain sterols; contain part of respiratory and, in some, photosynthetic machinery | Sterols present; do not carry out respiration and photosynthesis |
| Cell Wall | Peptidoglycan (murein or mucopeptide) as component | Absence of peptidoglycan |
| Locomotor organelles | Simple fibril (flagella) | Multifibrilled with “9+2” microtubules |
| Pseudopodia | Absent | Present in some |
| Metabolic mechanisms | Wide variety, particularly that of anaerobic energy yielding reactions; some fix nitrogen gas; some accumulate poly-β-hydroxybutyrate as reserve material | Glycolysis is pathway for anaerobic energy-yielding mechanism |
| DNA base ratios as moles % of guanine + cytosine (G+C%) | 28 to 73 | About 40 |
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