a)
Write a chemical equation to summarise how two molecules of glucose are joined
to form maltose. Structural formulae are not expected.
α Glucose + α Glucose Maltose + Water
b)
State two ways by which the reaction you have shown in (a) could be reversed.
Maltose could be broken
down into 2 glucose molecule by Maltase through hydrolysis.
ci)
Maltose and sucrose both have the same empirical formula, but different
structural formulae. What biochemical term is used to describe this?
Maltose is from aldehyde
group and sucrose is from keto group.
cii)
Maltose is a reducing sugar but sucrose is a non- reducing sugar. If you were
given a solution suspected to contain a mixture of these two sugars and asked
to prove their presence, describe the procedure you would use.
To test for the presence
of monosaccharides in Maltose and Sucrose, Maltose and Sucrose are dissolved in
water, and a small amount of Benedict’s reagent is added. During a water bath,
which is usually 4-10 minutes. A colour change will be observed. Brick red
precipitate will be obtain in Maltose because of the presence of glucose. On
the other hand, the sucrose solution will remains blue because it does not
react with Benedict’s reagent. If dilute hydrochloric acid is added into the
test, positive result will be obtain because acidic condition will break the
glycosidic bond in sucrose through hydrolysis. The products of sucrose
decomposition are glucose and fructose.
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