1. Cellular Structure:
* Bacteria:
* Prokaryotic: Lack a true nucleus and other membrane-bound organelles (like mitochondria, Golgi apparatus).
* Simpler: They have a cell wall, a cell membrane, cytoplasm, ribosomes, and DNA in a region called the nucleoid.
* Eukaryotic Cells:
* Eukaryotic: Have a true nucleus containing their DNA, and other membrane-bound organelles.
* Complex: They have a more intricate internal structure, including a cytoskeleton, endoplasmic reticulum, and lysosomes.
2. Size and Shape:
* Bacteria: Generally much smaller (1-10 micrometers) than eukaryotic cells (10-100 micrometers). They come in a variety of shapes like spheres (cocci), rods (bacilli), and spirals (spirilla).
* Eukaryotic Cells: Can be much larger, ranging from single-celled organisms like amoeba to complex multicellular organisms.
3. DNA Organization:
* Bacteria: Have a single circular chromosome located in the nucleoid region. They can also have smaller, circular DNA molecules called plasmids.
* Eukaryotic Cells: Have multiple linear chromosomes located within the nucleus.
4. Reproduction:
* Bacteria: Typically reproduce asexually through binary fission (simple cell division). They can divide rapidly, allowing for quick population growth.
* Eukaryotic Cells: Typically reproduce sexually, involving the fusion of gametes (sperm and egg).
5. Metabolism:
* Bacteria: Have diverse metabolic pathways, some of which are unique to bacteria, like nitrogen fixation. Some bacteria are capable of photosynthesis.
* Eukaryotic Cells: Have more limited metabolic capabilities. They primarily rely on oxygen for energy production.
6. Cell Wall:
* Bacteria: Have a rigid cell wall, often made of peptidoglycan. The composition of the cell wall can vary, which is used for classifying bacteria (Gram-positive vs. Gram-negative).
* Eukaryotic Cells: Some eukaryotic cells (like plant cells) have cell walls, but they are made of different materials like cellulose. Animal cells lack cell walls.
7. Organelles:
* Bacteria: Lack complex organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum.
* Eukaryotic Cells: Possess a variety of organelles that perform specialized functions within the cell.
8. Sensitivity to Antibiotics:
* Bacteria: Susceptible to many antibiotics that target bacterial-specific processes like cell wall synthesis or protein production.
* Eukaryotic Cells: Generally not affected by antibiotics that target bacteria.
These differences are what make bacteria distinct from the cells of organisms they infect and also make it possible to target bacteria with antibiotics without harming the host organism.
