Thank you for your answers! Just a quick question, how come a few years ago VCAA said that a hormone is "a chemical compound produced in a cell. It either acts within the cell or diffuses or is transported to other cells where it brings about a specific response," this implying paracrine autocrine and endocrine signalling?
Yeah, I know exactly what definition you are talking about - this could technically - given the vagueness of the definition imply both (i.e. paracrine signalling molecules diffuse between cells and initiate a specific response)... to be honest, if asked for the definition of a hormone - I would simply mention:
- Produced by a cell
- Transported between cells
- Act on specific target cells
- Initiate specific response.
Given that many different resources use the term 'hormone' interchangeably with 'signalling molecule', I wouldn't be too accurate in terms of the defintion (you cannot be sure which resources VCAA are using), hence, if VCAA are going to feed you vague definitions in past exams - I would also feed these similarly 'vague' definitions back... (NOTE: DO NOT try this with other types of questions, for example, in the 2016 VCAA Biology Exam, the level of detailed required for a transcription question increased relative to other years)
Hope this helps...