Hey guys, has anyone done the SAC on coordination and regulation?
Im so confused... Something to do with the stimulus?
I still don't fully understand signal transduction and hormones... the text book definitions are so confusing.
Hey vanessa14
I can give you a quick run down on hormones and signal transduction but I still haven't done the SAC for it yet. Hormones are basically chemical messengers in the body that are secreted/released (meaning specific glands produce them and release them) into the blood stream. Once in the blood stream, each hormone has a specific target cell that it needs to communicate with so that the stimulus can be regulated. This hormone molecule will travel through the bloodstream, passing many cells on its journey until it reaches its specific target tissue of cell. The hormone molecule then binds to its specific receptor, which has a complementary shape to the molecule, so that not any hormone can bind but only that specific one. Now, there can be intercellular receptors (called cytoplasmic receptors) or receptors in the cell membrane (called transmembrane receptors). Now from your studies in AOS1, you should know that the cell membrane is semi-permeable to only certain molecules, this means that lipid-soluble (lipophillic/hydrophobic) hormones can DIRECTLY diffuse through the membrane, so their specific receptors are inside the cell. But we have protein-based hormones, and we know that proteins are hydrophilic, so their chemical nature restricts them from diffusing through the membrane, so how will they communicate to the cell? Well, they bind to a receptor that's om the cell surface, and the message is related from there. So now that the hormone-receptor complex has been formed (a hormone has binded to its receptor), a series of chemical reactions occur where the message being communicated is related among other molecules. You do not need to know the specifics to the signal transduction pathways (beyond VCE levels). The end of the signal transduction pathway basically determines the cells response. The cells response can anything from producing new enzymes that will break down other molecules or even enzymes that bind molecules together! This is the cells response, it RECIEVED the message, it TRANSDUCTED the message, and then it RESPONDED to it. Obviously once the response has been carried out, the original hormone or one of the signalling molecules must be broken down so that the response can be regulated to prevent an over-stimulation!
I hope that helped, good luck with your SAC!