VCE Biology Question Thread

[geminii]

Your second question ( which for some reason I can't quote ) as far as I know both are correct. I was once told , however , that the formal definition of organic is the one Douchy mentioned and that the other one arises because all organic molecules tend to have oxygen anyways( think about the elements involved in carbs ,lipids , proteins and nucleic acids.

Thanks! But say if there was a molecule that had only carbon and hydrogen, would that be counted as an organic molecule? Or would it need to have an oxygen as well to be counted as organic? (aka what is the correct definition of an organic molecule and what it contains?)

And if they asked (in an exam) what an organic molecule consists of, should I write 'carbon and hydrogen', or 'carbon, hydrogen and oxygen'?

[sunshine98]

It's not letting me quote your post again , but yes. The thing is the chemistry definition afaik is that if it contains carbon and hydrogen it's considered organic. But the organic molecules which we look at in bio ( the 4 bio macromolecules ) all contain oxygen as well so that's what makes it kinda confusing. If I were asked a definition tho I would probably say something like "molecules containing carbon and hydrogen ( often also containing oxygen as demonstrated by the 4 biomacromolecules - carbs , lipids , proteins and nucleic acids ) " or something along those lines.

[geminii]

It's not letting me quote your post again , but yes. The thing is the chemistry definition afaik is that if it contains carbon and hydrogen it's considered organic. But the organic molecules which we look at in bio ( the 4 bio macromolecules ) all contain oxygen as well so that's what makes it kinda confusing. If I were asked a definition tho I would probably say something like "molecules containing carbon and hydrogen ( often also containing oxygen as demonstrated by the 4 biomacromolecules - carbs , lipids , proteins and nucleic acids ) " or something along those lines.

Ah, ok, thanks! That makes sense

[TheAspiringDoc]

yeh , I guess. But I think it would be better for u to think that:
- amino acid undergo condensation reactions to form proteins
And
- proteins undergo hydrolysis to form amino acids again
Also , worth noting that as a 'polymer' proteins are often referred to as polypeptides. I remember, however ,  that there was a quite small distinction between the terms proteins and polypeptides but as far as i know in vce bio it is quite negligible
Your second question ( which for some reason I can't quote ) as far as I know both are correct. I was once told , however , that the formal definition of organic is the one Douchy mentioned and that the other one arises because all organic molecules tend to have oxygen anyways( think about the elements involved in carbs ,lipids , proteins and nucleic acids.

is the distinction that polypeptides are only are sequence of peptide-bonded amino acids, whereas a protein also takes into account the higher structural levels of significance?

[geminii]

is the distinction that polypeptides are only are sequence of peptide-bonded amino acids, whereas a protein also takes into account the higher structural levels of significance?

Yea, that's right.
A polypeptide is primary structure, secondary structure and (sometimes) tertiary structure.
A protein is (sometimes) a tertiary structure and the quaternary structure.

[geminii]

Can anyone explain briefly what the difference (in structure AND function) is between the smooth ER and the rough ER? Also, what is the difference (in structure AND function) between the two ER's and the Golgi Apparatus?

Also, in how much detail do we need to know the stages of cellular respiration, particularly glycolysis? For example, in glycolysis there are several stages. Do we need to know how much of each input and output there are, for the exam?

Thanks!

[TheAspiringDoc]

Can anyone explain briefly what the difference (in structure AND function) is between the smooth ER and the rough ER? Also, what is the difference (in structure AND function) between the two ER's and the Golgi Apparatus?

Also, in how much detail do we need to know the stages of cellular respiration, particularly glycolysis? For example, in glycolysis there are several stages. Do we need to know how much of each input and output there are, for the exam?

Thanks!

rER: helps with protein synthesis, fuses carbohydrates and proteins to form glycoproteins (which then go into plasma membrane)

sER: lipid synthesis, carbohydrate metabolism, storage of calcium ions, detoxification of poisons and drugs.

Overall, the ER is involved in transport as well.

I'll get back to you on the other one a little later

[geminii]

rER: helps with protein synthesis, fuses carbohydrates and proteins to form glycoproteins (which then go into plasma membrane)

sER: lipid synthesis, carbohydrate metabolism, storage of calcium ions, detoxification of poisons and drugs.

Overall, the ER is involved in transport as well.

I'll get back to you on the other one a little later

Awesome, thanks! No rush

[sunshine98]

Can anyone explain briefly what the difference (in structure AND function) is between the smooth ER and the rough ER? Also, what is the difference (in structure AND function) between the two ER's and the Golgi Apparatus?

Also, in how much detail do we need to know the stages of cellular respiration, particularly glycolysis? For example, in glycolysis there are several stages. Do we need to know how much of each input and output there are, for the exam?

Thanks!

Amazing answer to ur first question  by TheAspiringDoc.
The Golgi Body/Apparatus /Complex's  function is mainly transport and storage in the cell( some of it kinda buds off to form vesicles to store things as well )
Your second question :
The SD requires you to know the "main inputs and outputs of glycolysis " so you just need the main ones. All the stages inside glycolysis is beyond the SD and hence not examinable. I think you need to know the amounts of each tho , particularly the number of ATP molecules formed at each stage.

[geminii]

Amazing answer to ur first question  by TheAspiringDoc.
The Golgi Body/Apparatus /Complex's  function is mainly transport and storage in the cell( some of it kinda buds off to form vesicles to store things as well )
Your second question :
The SD requires you to know the "main inputs and outputs of glycolysis " so you just need the main ones. All the stages inside glycolysis is beyond the SD and hence not examinable. I think you need to know the amounts of each tho , particularly the number of ATP molecules formed at each stage.

Ah, ok. So there's no need to know, like, which enzyme does what, and all that? I've seen some pretty complicated stuff related to glycolysis.
Thanks for the answers!

[heids]

Ah, ok. So there's no need to know, like, which enzyme does what, and all that? I've seen some pretty complicated stuff related to glycolysis.
Thanks for the answers!

I swear (especially with AspiringDoc's questions that would utterly stump me without a cheeky google ) that my only input to this thread is 'You Do Not Need To Know That' , but no, you don't.  Do be aware that while it's absolutely great to learn these things if you enjoy them and have the time, for most of the processes in Bio (respiration, photosynthesis, transcription/translation, immunity etc.) people round this site give far more detail than actually necessary.

Glycolysis, I'd just know that it's the breakdown of glucose into two pyruvates releasing 2 ATP, plus list the inputs and outputs.

[sunshine98]

Ah, ok. So there's no need to know, like, which enzyme does what, and all that? I've seen some pretty complicated stuff related to glycolysis.
Thanks for the answers!

Yh no enzymes and stuff like that. I think I attached a table a few pages back so you might want to see if you can find that , just to give you an idea of what you need to know. Also don't forget to know the locations at which they occur and the structure of the mitochondria.

[geminii]

Attached a table
hope it helps

Found the post, but when I click on the attached document it  says its not available. Any chance you could re-upload it?

Also thanks bangali! I can't quote your answer but your input was very helpful

[TheAspiringDoc]

I find it helps to find reasons for things when trying to understand the stages of cellular respiration. For example the chemical formula of pyruvate is C3H4O3. This shows us that of of the 12H from the initial glucose, 4 are 'emitted' and 2 are used to form 2 loaded carrier molecules of NADH, while 2 are left free for later use. 

Also, I'm trying to look back in this thead (about page 40 I think) to find this post by psyxwar that like detailed all of cellular resp.

[sunshine98]

Found the post, but when I click on the attached document it  says its not available. Any chance you could re-upload it?

Would've done it but unfortunately the Internet on my computer is not working for some reason so I'm on my phone. Sorry.
But it was basically a table with the stages ( glycolysis , kreb cycle , electron transport chain) on the horizontal end and verticle columns had input and outputs.