TABLE 2-1.
Comparison of Prokaryotes and Eukaryotes
| Feature | Prokaryotes | Eukaryotes |
|---|---|---|
| Chromosome | Single, circular or linear | Yes |
| Gene organization | Operon-polycistronic mRNA | Single genes and block of genes |
| Nucleosomes | No | Yes |
| Nuclear membrane | No | Yes |
| Mitosis | No | Yes |
| Introns in genes | No | Yes |
| Transcription | Coupled with translation | Separate from translation |
| mRNA | No terminal polyadenylation (except archaebacteria); polygenic | Terminal polyadenylation; usually monogenic |
| First amino acid | Unstable formylmethionine (except archaebacteria) | Methionine |
| Ribosome | 70S (30S + 50S) | 80S (40S + 60S) |
| Cell wall | Presence of muramic acid, d-amino acids, peptidoglycan (except archaebacteria and mycoplasma) | No muramic acid, d-amino acids or peptidoglycan |
| Membrane | No sterols or phosphatidyl-choline (except mycoplasma) | Sterols and phosphatidyl-choline |
| Endoplasmic reticulum | No | Yes |
| Mitochondria | No | Yes (Entamoeba histolytica, Giardia and microsporidia have vestigial remnants of mitochondria) |
| Lysosomes and peroxisomes | No | Yes |
| Movement | By flagella, composed of a single fiber | Ameboid, by cilia or cilia-like flagella |