Biology Unit 3 Questions Megathread

[HERculina]

are second messengers the same as relay molecules?
AND
the definition of signal transduction says that signal amplification happens. but with lipid-soluble hormones how does this happen when second messengers are not used

[Inside Out]

are 2nd messnegers relay molecules

[shinny]

are second messengers the same as relay molecules?
AND
the definition of signal transduction says that signal amplification happens. but with lipid-soluble hormones how does this happen when second messengers are not used

Second messengers are a type of relay molecule. That definition is just trying to stay broad once again to avoid losing marks unnecessarily. Signal transduction is a very loosely defined term. With lipid hormones, this happens because although they directly cause the transcription of DNA, the protein product which results is itself a relay molecule because that protein will go on to cause other effects.

[Inside Out]

is a g protein a 2nd messenger

[shinny]

is a g protein a 2nd messenger

Yes.

[Inside Out]

what does the term amplified mean

[HERculina]

but you know second messengers arent they non-protein. how does that work when relay molecules are proteins.
(sorry about all these questions ^^)

[shinny]

but you know second messengers arent they non-protein. how does that work when relay molecules are proteins.
(sorry about all these questions ^^)

Relay molecules aren't necessarily proteins.

what does the term amplified mean

Are you serious? =/ Hopefully you meant in the context of all of this then. Basically it's referring to fact that a single relay molecule could interact with a cell to produce a second messenger, then this second messenger can interact with 100 relay molecules, with these 100 relay molecules then interacting with another 1000 different relay molecules and so on, leading to the production of exponentially increased numbers of protein relative to the initial signal.

[HERculina]

but you know second messengers arent they non-protein. how does that work when relay molecules are proteins.
(sorry about all these questions ^^)

Relay molecules aren't necessarily proteins.

what does the term amplified mean

Are you serious? =/ Hopefully you meant in the context of all of this then. Basically it's referring to fact that a single relay molecule could interact with a cell to produce a second messenger, then this second messenger can interact with 100 relay molecules, with these 100 relay molecules then interacting with another 1000 different relay molecules and so on, leading to the production of exponentially increased numbers of protein relative to the initial signal.

ok. so if you think about it, relay molecules are everything in the cell involved in signal transduction except for the hormone-receptor complex?

and with the signal being amplified, could you also say that it means many responses can be produced in cytosol form one signal

[shinny]

but you know second messengers arent they non-protein. how does that work when relay molecules are proteins.
(sorry about all these questions ^^)

Relay molecules aren't necessarily proteins.

what does the term amplified mean

Are you serious? =/ Hopefully you meant in the context of all of this then. Basically it's referring to fact that a single relay molecule could interact with a cell to produce a second messenger, then this second messenger can interact with 100 relay molecules, with these 100 relay molecules then interacting with another 1000 different relay molecules and so on, leading to the production of exponentially increased numbers of protein relative to the initial signal.

ok. so if you think about it, relay molecules are everything in the cell involved in signal transduction except for the hormone-receptor complex?

and with the signal being amplified, could you also say that it means many responses can be produced in cytosol form one signal

You could possibly include that? I'm not sure. Once again, everything's fairly loosely defined here.

And yeh, you could probably interpret amplification that way as well.

[Kaille]

Would i be correct in saying that extracellular pathogens cause the humoral immune response and intracellular pathogens cause the cell-mediated response?

[Russ]

Yes, but intracellular pathogens can also cause humoral response and extracellular pathogens can cause CMI responses

[Kaille]

oh i see, but generally, in exam questions can i follow that "rule"?

for example if i had a question like how would t cells and b cells be involved in and infected cut on a finger, i would explain the humoral response?

[TrueLight]

well its not a set rule because both arms of the adaptive immune response are involved but if you were talking about extracellular bacteria for example, you would emphasise more the phagocytosis, inflammatory immune response, complement, DC activation, antibody response which would be the more predominant response... stuff like that

[WhoTookMyUsername]

In childbirth, is the effector the posterior pituitary or the uterus?

And how do you tell in general?