VCE Biology Question Thread

[Jason12]

vcaa has a paper about signal transduction on their website and they have the definition as this:

Signal transduction involves the conversion by a cell of an external stimulus to one or more internal events by a sequence of processes that take place in the cell plasma membrane.

this might be a dumb question, but should I always use that definition in sacs and possibly, the exam?

my previous definition was: a process by which a cell converts one signal into another

[Yacoubb]

vcaa has a paper about signal transduction on their website and they have the definition as this:

Signal transduction involves the conversion by a cell of an external stimulus to one or more internal events by a sequence of processes that take place in the cell plasma membrane.

this might be a dumb question, but should I always use that definition in sacs and possibly, the exam?

my previous definition was: a process by which a cell converts one signal into another

Use what VCAA uses. You can't go wrong there!

[jessica666]

is material covered in 1/2 assumed knowledge or not necessary? Obviously a lot of unit 1 is covered again in 3/4 but what about respiratory, circulatory, urinary systems etc ? also is any of unit 2 necessary as i have not completed unit 2

[alchemy]

is material covered in 1/2 assumed knowledge or not necessary? Obviously a lot of unit 1 is covered again in 3/4 but what about respiratory, circulatory, urinary systems etc ? also is any of unit 2 necessary as i have not completed unit 2

From here on in (past AOS1), most of the stuff hasn't been taught in Units 1/2. I don't think we have to know about those 'systems' you mentioned, in great detail.

[alchemy]

After the body has responded to a stimulus, that signal must be removed in order to prevent overreaction from happening. One way is to disrupt the signal pathway. Can someone please give an example of when and how the body does this?

[vox nihili]

After the body has responded to a stimulus, that signal must be removed in order to prevent overreaction from happening. One way is to disrupt the signal pathway. Can someone please give an example of when and how the body does this?

Enzymes. There are heaps of enzymes floating around to degrade signalling molecules, so that their binding is short lived.

[RazzMeTazz]

does signal transduction only occur in relation to hormones?
or with pheromones and nervous impulses as well?

since technically when a stimulus is present in the external environment (external stimulus) this is converted into a a series of internal events (nervous impulses), by cells?

[vox nihili]

does signal transduction only occur in relation to hormones?
or with pheromones and nervous impulses as well?

since technically when a stimulus is present in the external environment (external stimulus) this is converted into a a series of internal events (nervous impulses), by cells?

It occurs for all of them yes. And indeed for external stimuli like light (think retinae)

[RazzMeTazz]

Is intercellular fluid the same as interstitial/tissue fluid?

And does the extracellular fluid consist of blood plasma and interstitial fluid?

Also would the internal environment of unicellular organisms be their intracellular fluid?

 

[alchemy]

Is intercellular fluid the same as interstitial/tissue fluid?

And does the extracellular fluid consist of blood plasma and interstitial fluid?

Also would the internal environment of unicellular organisms be their intracellular fluid?

 

The term 'extra cellular fluid' refers to all body fluid outside of cells. Tissue fluid (or interstitial fluid) is a component of the extra cellular fluid. It consists of all the constituents of blood plasma, less the proteins. Yes, mammalian tissue contains tissue fluid in places such as the tiny channels and spaces between cells. Btw, I'm pretty sure intercellular fluid refers to the cytosol, so you shouldn't confuse if for interstitial or tissue fluid.

[RazzMeTazz]

The term 'extra cellular fluid' refers to all body fluid outside of cells. Tissue fluid (or interstitial fluid) is a component of the extra cellular fluid. It consists of all the constituents of blood plasma, less the proteins. Yes, mammalian tissue contains tissue fluid in places such as the tiny channels and spaces between cells. Btw, I'm pretty sure intercellular fluid refers to the cytosol, so you shouldn't confuse if for interstitial or tissue fluid.

oh okay thankyou!!

oh oops I thought intracellular fluid referred to the cytosol and intercellular fluid was between the cells  ahah sorry I think all these different types of fluids are confusing me!

[RazzMeTazz]

Can someone please give me an example of signal transferral?

Because all the different types of signals I can think of (hormones, nervous impulses etc) are relayed via signal transduction not signal transferal.

What is the difference between these two?
o.O

[vox nihili]

Can someone please give me an example of signal transferral?

Because all the different types of signals I can think of (hormones, nervous impulses etc) are relayed via signal transduction not signal transferal.

What is the difference between these two?
o.O

It's not a thing.

[grannysmith]

The term 'extra cellular fluid' refers to all body fluid outside of cells. Tissue fluid (or interstitial fluid) is a component of the extra cellular fluid. It consists of all the constituents of blood plasma, less the proteins. Yes, mammalian tissue contains tissue fluid in places such as the tiny channels and spaces between cells. Btw, I'm pretty sure intercellular fluid refers to the cytosol, so you shouldn't confuse if for interstitial or tissue fluid.

I think intercellular fluid refers to the fluid between cells (aka tissue fluid), whereas intracellular fluid refers to the internal fluid of the cell.

oh okay thankyou!!

oh oops I thought intracellular fluid referred to the cytosol and intercellular fluid was between the cells  ahah sorry I think all these different types of fluids are confusing me!

That's correct.

[RazzMeTazz]

Would we have to know what the different components of the stimulus-response model (receptor, co-ordinating centre, effector etc) are at a cellular level when hormones bind with the cell?

Eg: The receptor would be the protein receptor in the cytoplasm of the cell
      The co-ordinating centre would be the nucleus in which some genes are turned off and others are
       turned on
       The response would be the new proteins produced by the cell

^
Or does this not make sense at all and the stimulus-response model is only for overall responses such as when the blood glucose level rises?