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).
Most cells have: 1  A nucleus â controlling the activity of the cell. 2  Cytoplasm â where chemical reactions occur. 3  A cell membrane â to control the passage of substances in and out of the cell. 4  A Mitochondria which is where the energy is released from.ost cells have: 1  A nucleus â controlling the activity of the cell. 2  Cytoplasm â where chemical reactions occur. 3  A cell membrane â to control the passage of substances in and out of the cell. 4  A Mitochondria which is where the energy is released from.