alpha-glucose beta-glucose (1 Viewer)

[jackc91]

I've heard these terms before but don't understand the difference. Could somebody please explain. Thanks in advance.

 

[study-freak]

Alpha and beta glucose are both glucoses yet they have a slightly different structure. The difference in structure is summarised by "alpha is down, beta is up"-for hydroxyl groups at one end of the ring structure. Basically the only difference is the position of a hydroxyl group.

You might need to see a simplified diagram of both glucoses to understand what I'm talking about but cbb scanning them and posting- sorry xD.

google should give u the pictures (or some other replys)

 

[jackc91]

ahhh i see...
They are both glucose as they have the same atoms but differ in arrangement.
Thankyou very much.

 

[Omium]

Im pretty sure thats not examinable

 

[jackc91]

yeh but still handy to know

 

[Pwnage101]

Alpha and beta glucose are both glucoses yet they have a slightly different structure. The difference in structure is summarised by "alpha is up, beta is down"-for hydroxyl groups at one end of the ring structure. Basically the only difference is the position of a hydroxyl group.

You might need to see a simplified diagram of both glucoses to understand what I'm talking about but cbb scanning them and posting- sorry xD.

google should give u the pictures (or some other replys)

isn't it 'beta is up, alpha is down' ?

EDI: It all depends on how you've drawn it - if the CH₂OH attached to C-5 is 'up and the OH on C-1 is also up, then it is beta glucose.

see wikipedia: "When D-glucose is drawn as a Haworth projection or in the standard chain conformation, the designation α means that the hydroxyl group attached to C-1 is positioned trans to the -CH2OH group at C-5, while β means it is cis. An inaccurate but superficially attractive alternative method of distinguishing α from β is by observing whether the C-1 hydroxyl is below or above the plane of the ring; this may fail if the glucose ring is drawn upside down or in an alternative chair conformation. "

 

[Timothy.Siu]

beta is for cellulose i think lol
and the funny group alternates up and down or something

 

[study-freak]

isn't it 'beta is up, alpha is down' ?

I'm sorry, i have made a srs mistake.
edited the previous post

 

[Pwnage101]

I'm sorry, i have made a srs mistake.
edited the previous post

no worries

 

[gurmies]

Both alpha and beta alternate in terms of polymer structure....beta for cellulose, alpha for starch polymers

 

[xiao1985]

Small but useless fact: because the OH group alternate in the case of beta glucose, it causes the polarity of polymer to cancel out, resulting in the non-water soluability of cellulose. For the polymer of alpha glucose, the OH is aligned towards the same side of the polymer chain, making it much more water soluable.

Also, alpha and beta glucose equilibrate in water.

 

[Pwnage101]

interesting, yeh my teacher taught me how in water they equilibrate