Prokaryotes (Greek word: Pro- before and karyon- nucleus) are organisms without a cell nucleus or any membrane-bound organelles. It has a simple cell structure.
Eukaryotes (Greek word: true and karyon-nucleus) are organisms with a cell nucleus and other membrane-bound organelles. It has complex cell structures.
Difference between Prokaryotic cells and Eukaryotic cells
| Characteristics | Prokaryotic cells | Eukaryotic cells |
| Size of organism | 0.1-10 μm | 10-100 μm |
| Cell type | Unicellular | Unicellular to multicellular |
| Genetic system location | Nucleoid, chromatin body, or nuclear material | Nucleus, mitochondria, chloroplasts |
| Nucleus Nuclear membrane Nucleolus Chromosome Histone protein Nuclear division | Absent Absent Absent One Absent By binary fission | Present Present Present Many Present Mitotic nuclear division |
| Membrane-bound organelles | ||
| Mitochondria | Absent | Present |
| Ribosomes | 70S (50S+30S) | 80S (60S+40S) |
| Gas vacuoles | Can be present | Absent |
| Mesosomes | Present | Absent |
| Chloroplasts | Absent | May be present |
| Endoplasmic reticulum | Absent | Present |
| Lysosomes | Absent | Present |
| Peroxisomes | Absent | Present |
| Golgi structures | Absent | Present |
| Cytoplasmic membranes | Sterol is absent | Sterol is present |
| Cell wall | Peptidoglycan (murein or mucopeptide) as component | Absence of peptidoglycan |
| Locomotory organelles | Simple fibril | Multifibrilled with “9+2” microtubules |
| Pseudopodia | Absent | Present in some |
| Sexuality | Zygote nature is merozygotic (partial diploid) | Zygote is diploid |
| Pinocytosis | Absent | Present |
| 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 a pathway for an anaerobic energy-yielding mechanism |
| DNA base ratios as moles % of guanine+cytosine (G+C%) | 28 to 73 | About 40 |
| Cell division | Binary fission | Mitosis |
| Examples | Bacteria | Plants, animals, fungi, algae |
Pinocytosis is a type of endocytosis in which the living cells ingests liquid droplets.
References:
- Pelczar Jr., M., Chan, E., & Krieg, N. (2007). Microbiology (5th edition). Tata McGraw-Hill.
