Prokaryotes vs. Eukaryotes
The key difference between prokaryotic and eukaryotic cells lies in their genetic organization. A nucleus is a membrane-bound structure in eukaryotes that houses multiple chromosomes, while a nucleoid is an irregularly shaped region in prokaryotes that contains a single chromosome without a protective membrane.
Ribosomes, composed of ribosomal RNA and about 50 different proteins, are the protein factories in all cells. In prokaryotes, many cells move using flagella, whip-like structures that propel them through their environment. Some bacteria also have a capsule that protects them from being engulfed by predator cells.
The Golgi apparatus acts like the cell's post office, receiving proteins from the rough ER, then modifying, packaging, and shipping them to their final destinations. In plant cells, the Golgi also produces polysaccharides needed for cell wall construction.
💡 Cool Biology Fact: The endosymbiotic theory explains how mitochondria and chloroplasts came to exist inside our cells - they were once free-living bacteria that were engulfed by larger cells and developed a mutually beneficial relationship!
Chloroplasts, found only in plant and algae cells, are the sites of photosynthesis where sunlight energy is converted into sugar. Unlike animal cells, plant cells have rigid cell walls made of cellulose that provide structural support and protection.