Biomedicine Question Thread

[Shenz0r]

Hey where was that question from? I finished the exam wiki stuff but desperately need more practice

...I haven't even started exam wiki. Was it hard?

D or L as being either positive or negative is provided in this question for these set of examples.

Just because there are two groups which 'appear' to be the same (but are not actually so) doesn't mean that there isn't optical activity. I guess a way you could think of it is in chemistry even though molecules have the same numbers of atoms and elements in it, they can still be different. Even if they have the same bonds, they can still be different (stereoisomers).

But if a primary alcohol is produced, there aren't any chiral centres right? So theoretically they should be optically inactive right :/

[ferrsal]

I only did the MC (there are ~22) and they seem reasonable, some required more thinking than others and about 2 questions I was uncertain of (mostly to do with identifying the type of reaction because I am kinda bad at that)

[Destiny]

Omg, started the exam wiki and so far it seems so much easier than the 2009 paper wtf?

[Shenz0r]

I thought it would be better to save that exam for later?

[golden]

I thought it would be better to save that exam for later?

Save some for later; they will prove handy.

But if a primary alcohol is produced, there aren't any chiral centres right? So theoretically they should be optically inactive right :/

I hope I understand what you are saying. I apologise if I don't.

Look at say D-(+)-altrose, I'll use that unrelated example so you can still do the question:
If you reduce the aldehyde, it will become an alcohol as you have mentioned.
So now it has terminal alcohol groups. The carbons attached to these alcohols are not chiral. But all of the other carbons in the chain (4 of them) are chiral as they have different groups. Does that help?

[Destiny]

I thought it would be better to save that exam for later?

Exam or MST, I don't know. Now I realise that I wasted the 2009 paper because I couldn't do any of the questions!

[Russ]

2009 was the best year :3

[Shenz0r]

Save some for later; they will prove handy.

I hope I understand what you are saying. I apologise if I don't.

Look at say D-(+)-altrose, I'll use that unrelated example so you can still do the question:
If you reduce the aldehyde, it will become be an alcohol as you have mentioned.
So now it has terminal alcohol groups. The carbons attached to these alcohols are not chiral. But all of the other carbons in the chain (4 of them) are chiral as they have different groups. Does that help?

Oh right! Yes, I understand now. I didn't take into account all the other carbons on the Fischer Projection. So because they still have at least one chiral group, they can still have some optical activity.

In this case, is L-Galactitol optically inactive? I flipped it around upside down and sure enough, the mirror-image was superimposable so it was achiral. Hence B?

I wasn't able to tell that it was achiral just by looking at the groups branching off each carbon though, could someone explain to me how to do that?

[Belgarion]

anyone remember roughly how many marks the bio exam for first year biomed is?

[ferrsal]

Has anyone done the Chem MST? Just wondering what it's like in terms of difficulty

[cuppo5]

Is it possible to transfer to BioMed provided I get the marks in first year uni? Also, what prereqs would I definitely need? I'm doing Methods now

[Leronziia]

Anybody else finding chemistry incredibly boring and painful to learn? This semester cannot end quick enough...

[REBORN]

Anybody else finding chemistry incredibly boring and painful to learn? This semester cannot end quick enough...

Yes.

[ferrsal]

Yes... especially the new stuff with the new lecturer. He's nice but the content is completely uninteresting

PS does anybody know if the Chem MST is the same for everyone?

[Shenz0r]

The content's not that bad, although hearing all this pile of information the first time through feels pretty overwhelming.

The MST is slightly different for everybody, similar concept-related questions but they may vary some stuff.