Starch vs Cellulose: Which is Soluble in Water?

[parwana]

Starch vs Cellulose??

In general, starch is soluble in water but cellulose is insoluble in water. Choose the one statement that may be responsible for this observation.



a) Starch has more dipoles per monomer unit than cellulose

b) Cellulose is a hydrocarbon polymer

c) Only starch can form hydrogen bonds with water

d) Starch consists of ions

e) Cellulose molecules have a much higher molecular weight than starch molecules


i know a and b are wrong, so out of c, d and which is correct?

 

[Astronuc]

Apparently the correct answer is 'e'.

See cellulose, starch, and the comparison of the two.

Both use the same monomer - glucose - but all of the 1,4 bonds in starch are $$\alpha-$$glycosidic, whereas all such bonds in cellulose are $$\beta-$$glycosidic.

In the formation of starch, the link to the next ring is formed at the same angle the original OH was positioned, whereas in cellulose, the link to the next ring is formed at the opposite angle the original OH was positioned.

See also - http://webpages.marshall.edu/~chai/Classes_And_Labs/Chem327/notes327/chap12.ppt -(just click right mouse button and select Save Target As).

 

[ravenprp]

The correct statement is c) Only starch can form hydrogen bonds with water. Starch is composed of glucose monomers that have hydroxyl (-OH) groups, which can form hydrogen bonds with water molecules. Cellulose, on the other hand, has a different arrangement of glucose monomers that do not have as many hydroxyl groups available for hydrogen bonding with water. This makes starch more soluble in water compared to cellulose.