Organic 23: Carbohydrates

Question 1

Carbohydrate

Answer 1

polyhydroxy aldehyde or polyhydroxy ketone

Question 2

Monosaccharide

Answer 2

simple carbohydrate, one that on attempted hydrolysis is not cleaved to smaller carbohydrates; ex = glucose

Question 3

Disaccharide

Answer 3

on hydrolysis, is cleaved to 2 monosaccharides, which may be the same or different; ex = sucrose (glucose + fructose)

Question 4

Oligosaccharide

Answer 4

yields 2+ monosaccharides on hydrolysis; homogenous - each molecule of a particular one has the same # of monosaccharide units joined together in the same order as every other molecule of the same one

Question 5

Polysaccharides

Answer 5

hydrolyzed to many monosaccharides; almost always mixtures of molecules having similar, but not necessarily the same, chain length

Question 6

Aldoses

Answer 6

monosaccharides that are polyhydroxy aldehydes

Question 7

Ketoses

Answer 7

polyhydroxy ketones

Question 8

Furanose

Answer 8

5-membered cyclic hemiacetals of carbohydrates

Question 9

Pyranose

Answer 9

6-membered cyclic hemiacetals of carbohydrates

Question 10

Anomeric carbon

Answer 10

the ring carbon that is derived from the carbonyl group, the one that bears 2 oxygen substituents

Question 11

Haworth formulas

Answer 11

planar representations of furanose and pyranose forms of carbohydrates

Question 12

Mutarotation

Answer 12

the change in optical rotation that occurs when a single form of a carbohydrate is allowed to equilibrate to a mixture of isomeric hemiacetals

Question 13

Glycosides

Answer 13

large and important class of carbohydrate derivatives characterized by the replacement of the anomeric hydroxyl group by some other substituent

Question 14

Fischer glycosidation

Answer 14

glycosides are prepared by simply allowing a carbohydrate to react with an alcohol in the presence of an acid catalyst

Question 15

Alditols

Answer 15

products of carbohydrate reduction

Question 16

Aldonic acid

Answer 16

oxidation of CH=O yields this

Question 17

Uronic acid

Answer 17

oxidation of CH2OH yields this

Question 18

Aldaric acid

Answer 18

oxidation of CH=O and CH2OH yields this

Question 19

Kiliani-Fischer synthesis

Answer 19

version of the chain-extension sequence; proceeds through a cyanohydrin but uses a less efficient method for converting the cyano group to the required aldehyde

Question 20

Epimers

Answer 20

2 stereoisomers that have multiple chirality centers but differ in configuration at only 1 of them

Question 21

Glycolysis

Answer 21

the isomerization of D-glucose to D-fructose by way of an enediol intermediate is an important step in this complex process by which an organism converts glucose to chemical energy