Question

5. Carbohydrates

a. What is the molecular formula of all carbohydrates? How does this differ from hydrocarbons? How do monosaccharides like glucose and lactulose differ structurally if they have the same molecular formula?

b. What is the function of glycoproteins? Where would you find them in a cell? How does their structure support their function?

c. What is the difference between a monosaccharide, a disaccharide, an oligosaccharide, and a polysaccharide?

d. What are three ways monosaccharides differ from each other?

f. What is the function of polymerization reactions? Hydrolyzing reactions?

Answer 1

A.

(CH₂O)_n

​​​​​​​​​​​​Carbohydrates are biomolecules which are called as hydrates of carbon. They contain carbon Oxygen and hydrogen.

They are different from hydrocarbon in the presence of oxygen.

Monosaccharides have the same molecular formula but the structure is different because the arrangement of hydrogen and hydroxyl groups around carbon atom is different.

B.

Glycoproteins are molecules which are the combination of Carbohydrates and proteins. These are present on the surface of cell membrane and are associated with cell signalling.

C.

A monosaccharide is a sugar molecule which has only one unit. For example glucose and fructose.

A disaccharide is a sugar molecule which has two units. For example sucrose is a disaccharide of glucose and Fructose. In between glucose and Fructose, a glycosidic bond is present which joins them.

An oligosaccharide is a sugar molecule which has around 3 to 10 units. A polysaccharide is a sugar molecule which has more than 10 repeating units. For example cellulose is a unbranched polysaccharide of glucose, glycogen is a branched polysaccharide of glucose.

D.

Monosaccharides differ with each other by the arrangement of hydroxyl group and hydrogen group around carbon atom.

The second difference is that a monosaccharide with same molecular formula can be either linear or cyclic.

Third difference - A linear monosaccharide can be either a ketose sugar or an Aldose sugar. A cyclic monosaccharides can be either pyranose or furanose.

E.

Polymerization reactions are condensation reaction which are meant for the formation of large size Polymers from simple small sized monomeric units. These involve loss of water molecule.

Hydrolyzing reactions are associated with breakdown of large Polymers into simple monomeric units.

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