BIOCHEMISTRY

1. 'Which of the following statements best characterize glucose?

It usually exists in the furanose form

It is a ketose

It forms part of the disaccharide sucrose

Only the L-isomer can be transported into mammalian cells

glucose is an aldose (not ketose), the predominantly naturally occuring isomers are the D-isomers which are easily transported into mammalian cells

Explanation

glucose is an aldose (not ketose), the predominantly naturally occuring isomers are the D-isomers which are easily transported into mammalian cells

About This Quiz

Covers chemical stucture of biomoleculesmajor biomolecules are carbohydrates, lipids, proteins and nucleic acids

2. As a rule, the number of isomers that a sugar has depends on

The number of chiral carbons

The kind of substituents

The number of alcohol groups present

Its anomeric carbon

the number of isomers is equal to the square of the number of chiral or assymetric carbon atoms (n raised to 2nd power). Thus glucose has 4 chiral carbons; its isomers total 16 (4 raised to the power 2).

Explanation

3. The simplest of the hydrated carbons, with the formula (CH2O1) is called

Dihydroxyacetone

Formaldehyde

Pyranose

Glyceraldehyde

glyceraldehyde fulfills the definition of carbohydrate: "polyhydroxyaldehydes or ketones". It has an aldehyde (-CHO) and 2 (i.e. poly) hydroxyl (-0H) groups.

Explanation

glyceraldehyde fulfills the definition of carbohydrate: "polyhydroxyaldehydes or ketones". It has an aldehyde (-CHO) and 2 (i.e. poly) hydroxyl (-0H) groups.

4. All of the following are composed exclusively of glucose, EXCEPT:

Amylose

Lactose

Cellulose

Maltose

Glycogen

lactose is made up of glucose + galactose; all the others are made up of glucose only

Explanation

lactose is made up of glucose + galactose; all the others are made up of glucose only