Bacteria are prokaryotes. They are single-celled organisms and microscopic. It does not have well defined nucleus and cell organelles. Thus, mitochondria is absent in them.

1. It is secreted in the adrenal gland into the medulla as well as in some neurons of the central nervous system.

2. It is known as an emergency hormone because it initiates an instant response that causes the person to think about the stress and react quickly.