A-Level Biology Edexcel B 9BI0

Understand the principles of mammalian hormone production by endocrine glands and their mode of action involving receptors on target cells.

Know that there are two main modes of action in hormones:

• hormones attach to receptor sites and trigger the release of a second messenger that activates specific enzymes in the cell, including adrenaline
• hormones enter cells and bind directly to transcription factors, including oestrogen.