Cell Structure
Cells are the basic building blocks of all living things, with two main types: eukaryotic and prokaryotic. Eukaryotic cells are found in animals, plants, fungi, and protista, measuring 10-100 micrometers in diameter. They have a nucleus containing DNA, a cell membrane, and cytoplasm.
Animal and plant cells share common features but have key differences. Both contain a cell membrane (controlling what enters and leaves), cytoplasm (where chemical reactions occur), ribosomes (for protein synthesis), and mitochondria (where energy is transferred during respiration). Plant cells have additional structures like a cellulose cell wall for strength, chloroplasts for photosynthesis, and a large permanent vacuole that makes the cell rigid.
Prokaryotic cells, like bacteria, are much smaller (0.1-5.0 micrometers) and simpler. Unlike eukaryotes, they don't have a nucleus - their DNA floats in the cytoplasm or exists as plasmids (loops of DNA). They often have a cell wall, slime capsule for protection, and flagellum for movement.
Did you know? Scientists use "orders of magnitude" to describe size differences. If something is 10 times bigger, it's 10¹ bigger; 1000 times bigger is 10³ bigger. This helps compare the vast size differences between cell types!
