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AQA Biology A2 Assistance Needed

I am stuck on a few understandings from the Nelson Thornes Text Book and would really appreciate some guidance.
In the text document I will write what ‘text (from the text book) I am having trouble in understanding and then my understanding of it so you guy’s can correct me exactly where I am going wrong please.
Just to provide ease of understanding of what I am trying to put across: TB= Text Book (what they say) and MU= My Understanding.
(edited 10 years ago)
Reply 1
Original post by king101
I am stuck on a few understandings from the Nelson Thornes Text Book and would really appreciate some guidance.
In the text document I will write what ‘text (from the text book) I am having trouble in understanding and then my understanding of it so you guy’s can correct me exactly where I am going wrong please.
Just to provide ease of understanding of what I am trying to put across: TB= Text Book (what they say) and MU= My Understanding.

To anyone that can answer all my queries in enough sense that would allow me to understand my confusion I will send £5.00 via paypal. The reason for the cash is since my understanding of these bits sucks and I’m really panicking.

Firstly mate, I think we are all out here to help others on a community basis, not for monetary means -_-

Now, coming to the confusion itself. You have assumed a lot on the basis of functioning of insulin/pancreas etc etc. In the first case, then: The receptors for hormones are proteins, that undergo a structural change when hormones bind to them. This leads to triggering of chemical (not electrical) events inside the cell that ultimately lead to response by effector.
EXAMPLE: when a ligand, such as acetylcholine binds to a specific receptor called a G-protein linked receptor (skip that), the receptor undergoes a conformational change, which leads to replacement of GDP by GTP. This is a chemical event, which ultimately leads to the cell response (GTP bound proteins activate the receptor by causing a conformational change in it and/or phosphorylating it, which leads to a series of events blah blah blah, but we needn't go into that now).

Second: you assume that the book is wrong when it says that hormones are secreted by glands because of the specific case of pancreas. Tbh, hormones are secreted from certain cells (or regions, such as adrenal medulla and adrenal cortex), but aside from pancreas (which is both exocine and endocrine) the hormonal secretion is taken generally as being from a certain gland called an endocrine gland.

In case of that thingummy about neurotransmitters, Ach binds to a specific receptor called an Ach receptor. This leads to a hell load of cell signaling you won't find relevant, before the voltage gated channels open.

Hormones target cells as well as organs.

About plants: they have hormones called growth factors, which have no relation to insulin whatever. I don't know from where you picked up that one.

I can't answer the rest of these, since I am short of time. Hope it helps! :biggrin:
Reply 2
Original post by Dynamo123
Firstly mate, I think we are all out here to help others on a community basis, not for monetary means -_-

Now, coming to the confusion itself. You have assumed a lot on the basis of functioning of insulin/pancreas etc etc. In the first case, then: The receptors for hormones are proteins, that undergo a structural change when hormones bind to them. This leads to triggering of chemical (not electrical) events inside the cell that ultimately lead to response by effector.
EXAMPLE: when a ligand, such as acetylcholine binds to a specific receptor called a G-protein linked receptor (skip that), the receptor undergoes a conformational change, which leads to replacement of GDP by GTP. This is a chemical event, which ultimately leads to the cell response (GTP bound proteins activate the receptor by causing a conformational change in it and/or phosphorylating it, which leads to a series of events blah blah blah, but we needn't go into that now).

Second: you assume that the book is wrong when it says that hormones are secreted by glands because of the specific case of pancreas. Tbh, hormones are secreted from certain cells (or regions, such as adrenal medulla and adrenal cortex), but aside from pancreas (which is both exocine and endocrine) the hormonal secretion is taken generally as being from a certain gland called an endocrine gland.

In case of that thingummy about neurotransmitters, Ach binds to a specific receptor called an Ach receptor. This leads to a hell load of cell signaling you won't find relevant, before the voltage gated channels open.

Hormones target cells as well as organs.

About plants: they have hormones called growth factors, which have no relation to insulin whatever. I don't know from where you picked up that one.

I can't answer the rest of these, since I am short of time. Hope it helps! :biggrin:


Thank's a ton mate. Yep helped a great deal and don't worry Munrot helped me a great deal with those others!

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