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Biochemistry questions (lipids)

Just a few questions I'd be grateful if anyone could clear up.

1) When is it a glycosidic bond and when is it an ester bond? I know bonds between all carbohydrates are glycosidic, but what if it's for example a fatty acid (which isn't a carb) attached to sucrose (which is)?

2) Starting with separate molecules of glucose, fructose and fatty acids. how many molecules of water would be produced when one molecule of olestra is formed?

I thought it would be 10 since there are 8 fatty acids, plus the bond called X and then fructose had to join to sucrose, but apparently it's 9? Thanks!

Thanks!
Original post by Qaiys
Just a few questions I'd be grateful if anyone could clear up.

1) When is it a glycosidic bond and when is it an ester bond? I know bonds between all carbohydrates are glycosidic, but what if it's for example a fatty acid (which isn't a carb) attached to sucrose (which is)?

2) Starting with separate molecules of glucose, fructose and fatty acids. how many molecules of water would be produced when one molecule of olestra is formed?

I thought it would be 10 since there are 8 fatty acids, plus the bond called X and then fructose had to join to sucrose, but apparently it's 9? Thanks!

Thanks!


A glycosidic bond is an ether linkage, it is a bridging oxygen between two alkyl carbons.

There are eight fatty acids and one glycosidic link + 9 water molecules.
Reply 2
Original post by Qaiys
Just a few questions I'd be grateful if anyone could clear up.

1) When is it a glycosidic bond and when is it an ester bond? I know bonds between all carbohydrates are glycosidic, but what if it's for example a fatty acid (which isn't a carb) attached to sucrose (which is)?

2) Starting with separate molecules of glucose, fructose and fatty acids. how many molecules of water would be produced when one molecule of olestra is formed?

I thought it would be 10 since there are 8 fatty acids, plus the bond called X and then fructose had to join to sucrose, but apparently it's 9? Thanks!

Thanks!


The two bonds highlighted are the same.

EDIT: Oh you said fructose joins TO sucrose. That is incorrect, see the post below for more information. The bond called X is holding the sucrose together.
(edited 9 years ago)
Original post by Qaiys
Just a few questions I'd be grateful if anyone could clear up.

1) When is it a glycosidic bond and when is it an ester bond? I know bonds between all carbohydrates are glycosidic, but what if it's for example a fatty acid (which isn't a carb) attached to sucrose (which is)?

2) Starting with separate molecules of glucose, fructose and fatty acids. how many molecules of water would be produced when one molecule of olestra is formed?

I thought it would be 10 since there are 8 fatty acids, plus the bond called X and then fructose had to join to sucrose, but apparently it's 9? Thanks!

Thanks!


fructose joins to glucose to make sucrose ...
Reply 4
Original post by charco
fructose joins to glucose to make sucrose ...


I meant wouldn't the fructose also have to join glucose to make sucrose, plus all the other bonds?
Reply 5
Original post by Qaiys
I meant wouldn't the fructose also have to join glucose to make sucrose, plus all the other bonds?


The bond between glucose and fructose is bond X
Reply 6
Original post by Exon
The bond between glucose and fructose is bond X


Ohhhh, I thought that was joining the fatty acid to the sucrose but I realise that's stupid, I understand now thankkks :smile:

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