4.3 Monosaccharides

Question 1

Monosaccharides

Answer 1

• contain alcohols and either aldehydes or ketones
• these functional groups undergo the same reactions that they do when present in other compounds
• Including: oxidation and reduction, esterification, and nucleophilic attack (creating glycosides)

Question 2

What type of rxn is required to make carbohydrates into energy?

Answer 2

• Oxidation, of the carbs.

Question 3

Aldonic acids

Answer 3

• oxidized aldoses
• reducing agents

Question 4

Reducing Sugar

Answer 4

• any monosaccharide with a hemiacetal ring

Question 5

Lactone

Answer 5

• When an aldose in ring form is oxidized, creates a cyclic ester with a carbonyl group persisting on the anomeric carbon

Question 6

What reagents are used to detect the presence of reducing sugars?

Answer 6

Tollens’ reagent and Benedict’s reagent

Question 7

Tollens’ reagent

Answer 7

• Silver oxide is dissolved in ammonia to produce [Ag(NH3)2]+, the actual Tollens’ reagent

Question 8

Benedict’s reagent

Answer 8

• the aldehyde group of an aldose is readily oxidized,
  indicated by a red precipitate of Cu2O,

Question 9

Tautomerization

Answer 9

the rearrangement of bonds in a compound, usually by moving a hydrogen and forming a double bond

Question 10

Enol

Answer 10

• a compound with a double bond and an alcohol group

Question 11

Alditol

Answer 11

• When the aldehyde group of an aldose is reduced to an alcohol

Question 12

Deoxy sugar

Answer 12

• contains a hydrogen that replaces a hydroxyl group on the sugar

Question 13

What rxn do hydroxyl groups on carbs participate in?

Answer 13

• *Esterification
• they are able to participate in
  reactions with carboxylic acids and carboxylic acid derivatives to form esters
• very similar to the phosphorylation of glucose, in which a phosphate ester is formed

Question 14

How do Glycosides form?

Answer 14

• Hemiacetals form acetals with alcohol. Then Anomeric hydroxyl group transforms into alkoxy and glycosidic bonds along with glycosides.
• glycoside formation is a dehydration reaction
• Glycosides derived from furanose rings are referred to as furanosides and those derived from pyranose rings are called pyranosides

Question 15

How do Disaccharides and polysaccharides form?

Answer 15

-as a result of glycosidic bonds
between monosaccharides