Starch vs Cellulose??

[parwana]

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 (http://hyperphysics.phy-astr.gsu.edu/hbase/organic/carb.html#c4), starch (http://hyperphysics.phy-astr.gsu.edu/hbase/organic/carb.html#c3), 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).