Eukaryotic Cell Structures
The nucleus is basically the cell's control centre - think of it as the brain that runs the whole show. This powerhouse contains your genetic material (DNA) and controls everything from cell division to protein production.
The nucleus has five key parts you need to know. The nuclear envelope is a double membrane covered in ribosomes that acts like a protective barrier. Nuclear pores work as gatekeepers, letting important molecules move in and out. Inside, you'll find nucleoplasm - a jelly-like substance that fills the space.
Your chromosomes live here too, containing linear DNA wrapped around proteins called histones. The nucleolus is particularly important because it's where ribosomes are made and RNA is produced. This is where DNA replication and transcription happen - processes you'll definitely see on your exams.
Mitochondria are often called the cell's powerhouses, and for good reason. These double-membraned organelles are where aerobic respiration takes place, producing the ATP that fuels cellular activities. The inner membrane folds into structures called cristae, which massively increase surface area for ATP production. The fluid centre, called the mitochondrial matrix, contains the cell's own loop of DNA to code for essential respiratory enzymes.
Key Tip: Remember that mitochondria have their own DNA - this supports the theory that they were once independent bacteria that became part of eukaryotic cells!