churn in American English. churnverb [ I/T ] [ I ] The water was churning and the boat was rocking. [ M ] The fish churned up the water when we threw them some food. [ T ] fig. Seeing the car ahead flip over churned his stomach.
Animal cells and plant cells both contain: 1  cell membrane. 2  cytoplasm. 3  nucleus. mitochondria.
Basically it controls everything that happens inside the cell, it's like a boss of the cell. People also call it the brain of the cell. But, the nucleus does not control everything. There is one part the nucleus cannot control, it is the cell membrane. The cell membrane controls what gets in or out of the cell.