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.
The nucleus controls everything that happens in the cell. This means that it controls the chemical reactions that take place in both and animal and plant cells. Some organelles in the cell have their own job like mitochondria control the respiratory (for example).
The cell membrane (or plasma membrane) surrounds all living cells. It controls how substances can move in and out of the cell and is responsible for many other properties of the cell as well. The membranes that surround the nucleus and other organelles are almost identical to the cell membrane.