Polysaccharides help

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

Moderators: Leonid, amiradm, BioTeam

Post Reply
User avatar
Navin
Coral
Coral
Posts: 277
Joined: Thu Jun 09, 2005 2:23 pm
Location: Singapore (Asia Pacific)

Polysaccharides help

Post by Navin » Wed Jan 25, 2006 11:22 am

I have learnt in school about 3 polysaccharides: starch, glycogen and cellulose and know their structural formula.

I also fully understand how the structure of cellulose allows it to become a structural polysaccharide in plants.

However I do not understand some things. What is it that starch and glycogen have that make them storage polysaccharides?

Also, why is it that glycogen is the storage polysaccharide in animals/fungi whilst starch is the storage polysaccharide in plants and not vice-versa?
Botany is the study of what? Bottoms!

User avatar
victor
King Cobra
King Cobra
Posts: 2668
Joined: Sat Apr 30, 2005 12:01 pm
Location: Yogyakarta, Indonesia..
Contact:

Post by victor » Wed Jan 25, 2006 11:37 am

that make them storage polysaccharides?? they ARE polysaccharides...a polymer of glucose.
for the second question, I can think that it's about the enzyme contained in each organisms..
Q: Why are chemists great for solving problems?
A: They have all the solutions.

User avatar
Navin
Coral
Coral
Posts: 277
Joined: Thu Jun 09, 2005 2:23 pm
Location: Singapore (Asia Pacific)

Post by Navin » Wed Jan 25, 2006 12:55 pm

I think you mistook what i said. When i say " storage polysaccharides" i mean polysaccharides whose function is for storage. Do you get it now?

So to further elaborate on my question: Why is starch used as for storage? Is it because of its structure? ...
Botany is the study of what? Bottoms!

fran008
Garter
Garter
Posts: 39
Joined: Thu Oct 13, 2005 7:48 pm
Location: Malta

Post by fran008 » Wed Jan 25, 2006 2:19 pm

The reason is because starch or glycogen in that matter are polymers of glucose/fructose- they have many units join together which they can hydrolyse to monomers and use them as energy. The energy store is the monomers themselves. They will be broken down to provide energy when needed.

User avatar
Navin
Coral
Coral
Posts: 277
Joined: Thu Jun 09, 2005 2:23 pm
Location: Singapore (Asia Pacific)

Post by Navin » Wed Jan 25, 2006 2:37 pm

Ok, then why is it that cellulose is not used for storage?
Botany is the study of what? Bottoms!

User avatar
MrMistery
Inland Taipan
Inland Taipan
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)
Contact:

Post by MrMistery » Wed Jan 25, 2006 7:41 pm

For the second question: less energy is spent to create/break down starch as oposed to glycogen, so plants use it. Animals, on the other hand use glycogen because it is much more easy to break down(the reaction is faster)- this is because of it's structure that has "branches"(didn't find a translation)
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

User avatar
Navin
Coral
Coral
Posts: 277
Joined: Thu Jun 09, 2005 2:23 pm
Location: Singapore (Asia Pacific)

Post by Navin » Thu Jan 26, 2006 7:27 am

Thank you people, I understand it now. Oh yes it is ok to call it "branches". That is what my lecturer called them too.
Botany is the study of what? Bottoms!

User avatar
victor
King Cobra
King Cobra
Posts: 2668
Joined: Sat Apr 30, 2005 12:01 pm
Location: Yogyakarta, Indonesia..
Contact:

Post by victor » Thu Jan 26, 2006 8:32 am

glycogen is composed of glucose polymer by forming alpha-1,4-glycosidic bond while cellulose is beta-1,4-glycosidic bond..this beta isoform have a stronger bonding so it would take lots of energy to breakdown those bonds...
Q: Why are chemists great for solving problems?
A: They have all the solutions.

User avatar
Navin
Coral
Coral
Posts: 277
Joined: Thu Jun 09, 2005 2:23 pm
Location: Singapore (Asia Pacific)

Post by Navin » Thu Jan 26, 2006 8:37 am

1. Then since like mr.mistery said, that starch requires less energy to break than glycogen, does that mean that the alpha 1,6 glycosidic bond requires more energy to break than the alpha 1,4 glycosidic bond?

2.
on the other hand use glycogen because it is much more easy to break down(the reaction is faster)- this is because of it's structure that has "branches"(didn't find a translation) - MrMistery


How does having branches lead to that?
Botany is the study of what? Bottoms!

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests