Cell Structure and Organisation

Prokaryotic cells (like bacteria) are the simpler cousins in the cell family - they don't have a proper nucleus or fancy internal compartments. Instead, they've got some brilliant survival features that help them thrive almost everywhere.

The cell wall acts like a protective suit of armour, made from a tough material called peptidoglycan that keeps the cell's shape intact. Many bacteria also sport a capsule - think of it as a slimy outer coat that helps them stick to surfaces and retain moisture (pretty handy when you're trying to survive on a kitchen worktop!).

Flagella work like tiny propellers, whipping around to help bacteria swim towards food or away from danger. Pili are like molecular grappling hooks that let bacteria grab onto other cells. Inside, ribosomes churn out proteins, whilst mesosomes (infoldings of the membrane) house the enzymes needed for respiration.

Quick Tip: Remember that prokaryotic cells pack all their essential functions into one compartment - no separate rooms like in human cells!

Meanwhile, viruses aren't even proper living things - they're basically genetic material (DNA or RNA) wrapped in a protein coat called a capsid. Some get an extra lipid envelope for protection, but they can't do anything on their own.