Question

I.-(3 pts) What is the structural difference between an aldose and a ketose 2. (2 pts) Which two functional groups are present in all monosaccharides? 3. (4 pts) Wha is the name of the molecule below? Which enantiomer is represented? C-H но-с-н CH2OH 4. (2 pts) Wha property of a pair of molecules results in the formation of enantiomers? 5. (3 pts) How are the symbols D- or L- assigned in naming a sugar? 6. (3 pts The following disaccharides are formed from which monosaccharides? a) Maltose b) Lactose c)Sucrose 7. (2 pts) There are two metabolic conditions associated with lactose. One is life threatening and is called The other causes intestinal discomfort and is called 8. (1 pt) Glucose oxidase is an enzyme that oxidizes glucose toacid.

Answer 1

Answer 1

Aldoses are those monosaccharides which contains aldehyde group.

Ketoses are those monosaccharides which contains ketone group.

H_COH CH2OH CH2OH glyceraldehyde dihydroxyacetone

Glyceraldehyde is a simplest aldose and dihydroxyacetone is simplest ketone.

Answer 2

All monosaccharides contain carbonyl (either aldehyde or ketone) and alcohol group.

Answer 3

The molecule given is Glyceraldehyde.

Enantiomer is  L

It is designated as L because -OH group on second last carbon is on left.

Answer 4

The property of molecule that result in enantiomerism is the chirality i.e. presence of four different groups on a carbon atom.

Answer 5

D- and L- are designated on the basis of direction of -OH on second last carbon.

If -OH is present on left, it is designated as L

If -OH is present on right, it is designated as D.

(CHOH)n (CHOH)n OH CH2OH CH20H D- sugar L- sugar

Answer 6

a) Maltose : 2 glucose units

b) Lactose : Galactose and Glucose

c) Sucrose : Glucose and Fructose

Answer 7

First blank Galactosemia (inability to metabolize galactose)

Second blank Lactose intolerance (deficiency of lactase enzyme)

Answer 8

Gluconic acid