Tea.towel's Biology questions

[pi]

LOLsure jw

lol

New Question: Can you guys tell me how deep I have to know photosynthesis and cellular respiration (basically ch.3 NOB)
I don't feel that NOB goes deep enough for the "light-independent reactions"

Should know how to draw a basic diagram as well and know all the electron carriers (by acronym) and make sure you know which comes in where in the respected cycles.

[simpak]

You need to know a lot for them a lot of people muck up!  Obviously the equations but also where each stage occurs and what happens in each stage.  This is extremely important for cellular resp. because a lot of people muck up here.  Look on youtube because there should be some good videos on light independent stage and the deal with all of that.

Basically, you should know how each substance is formed or consumed during the process - at which stage and as a result of what, etc.  I think my school's notes covered this quite well for both processes, so have a look at those if you like.

[tea.squaredd]

New Question:
Do Lipid based hormones (i.e. steroid hormones) initiate/trigger signial transduction? S: Or is it water-soluble hormones only?

An explanation would be nice also

[Russ]

New Question:
Do Lipid based hormones (i.e. steroid hormones) initiate/trigger signial transduction? S: Or is it water-soluble hormones only?

An explanation would be nice also

What sort of explanation do you want?

I usually think of signal transduction as the domain of hormones that can't cross the membrane (ie not steroid hormones) because they're the only ones actually transducing anything.

I guess it's not really that big a deal, it still works the same way

[tea.squaredd]

Russ, are you saying its water-soluble hormones only?

[Russ]

It's just that since you specifically refer to transduction, I'm not sure if steroid hormones would qualify.

Obviously if they bind a cytosolic receptor then a signal can't be transduced across the membrane. Might want to do a bit of research or ask a teacher. Both are certainly capable of triggering gene transcription, which is usually the end result of hormone signalling

[shinny]

Mmm yeh, I see the problem here that Russ has brought up =/ Never thought of it like that but it's a fair point. For example, glucocorticoids (a type of steroid) pretty much bind to an intracellular receptor, and this complex then moves into the nucleus and binds to promoter regions on target genes. Other steroids operate in a similar manner. Given that there isn't really an amplification of the signal, I would be hesitant to call this transduction as well. I think it really depends on what definition you use. Some sources seem to use it just to state any sort of extracellular message changing something intracellularly. I've seen other definitions which mention it must specifically bind to extracellular receptors. However, the VCE definition seems to always require mentioning some sort of amplification of the signal if I remember correctly, so I'd stick with this one. Either way, doubt it's going to be tested. Just know your definition of signal transduction word for word (probably comes up every second VCAA exam) and you'll be fine.