Chapter 4: Carbohydrate Structure and Function

Question 1

aldoses

Answer 1

aldehyde group as their most oxidized fucntional group

Question 2

ketoses

Answer 2

ketone group as their most oxidized fucntional group

Question 3

glyseraldehyde

Answer 3

basic structure of an monosaccharide

Question 4

dihydroxyacetone

Answer 4

simplest ketose

Question 5

enantiomers

Answer 5

nonidentical, nonsuperimposable mirror image of each other. it is different in every chiral carbon. they must be opposite absolute configurations

Question 6

number of stereoisomers with common backbone=

Answer 6

2^n

n is the number of chiral carbons

Question 7

horizoantal lines are wedges and are _____

Answer 7

out of page

Question 8

vertical lines are dashes and are ____

Answer 8

into the page

Question 9

D- sugars have their hydroxide group of thier highest chiral center on their ___

Answer 9

right

Question 10

L- sugars have their hydroxide group of thier highest chiral center on their ___

Answer 10

left

Question 11

3 types of stereoisomers:

Answer 11

1) enantiomers: the same sugar in different optical families (such as D-gluose and L-glucose)
2) diastereoisomers: 2 sugars that are in the same family, but are not identical and are not mirroe images of each other
3)epimers: diastereomer that differes in only once chiral center

Question 11

hemiacetal

Answer 11

from aldoses

Question 12

hemiketal

Answer 12

from ketoses

Question 12

pyranoses

Answer 12

six-membered rings

Question 13

furanose

Answer 13

five-membered rings

Question 14

anomers

Answer 14

two molecules that differ in their anomeric crbon, they can be alpha and beta.

Question 15

haworth projection

Answer 15

any group in the right of a fisher projection goes down in the haworth projection

Question 15

beta-anomer

Answer 15

has the -OH group on the C-1 cis to the CH2OH substituint (equatorial and up)

Question 15

alpha-anomer

Answer 15

has the -OH group on the C-1 trans to the CH2OH substituint (axial and down)

Question 16

mutarotation

Answer 16

exposing hemiacetal rings to water will cause them to open and close

interconversion between alpha and beta anomers via ring open and close

the alpha anomer configuration is less favorabke because the hydroxyl group of the anomeric carbon is axial, adding to the steric hinderance of the molecule

Question 17

aldonic acids

Answer 17

oxidized aldoses, they are carboxylic acids

Question 18

reducing sugar

Answer 18

any monosaccharide with a hemiacetal ring

Question 19

lactone

Answer 19

cyclic ester with a carbinyl group persisting on the anomeric carbon. Contains a cyclic ester.

Question 20

tollen’s reagent

Answer 20

produce a silvery mirror when aldehyde are present

Question 21

tautomerization

Answer 21

ketones can be tautomerized to form a aldose under basic conditions via keto-enol shifts. it does the rearrangement of bonds in a compound, usually by moving a hydrogen and forming a double bond.

Question 21

benedict’s reagent

Answer 21

red precipitate of Cu2O

Question 22

enol

Answer 22

compond with a double bond and a alcohol group

Question 23

esterification

Answer 23

carboxylic acid derivatives to form esters

Question 24

phosphate ester

Answer 24

esterification is very similar to the phosphorylation of glucos in which phosphat ester is formed

Question 25

hemiacetals react with alcohol to form ___

Answer 25

acetals

Question 26

glycoside formation

Answer 26

the anomeric hydroxyl group is tranformed into a alkoxy group, yielding a mixture of alpha and beta acetals (with water as a leaving group). The resulting is a carbon-oxygen (C-O) bonds are called glycosidic bonds, and the acetals formed are glycosides.

Question 27

sucrose

Answer 27

glucose-alpha-1,2 - fructose

Question 27

disaccharides

Answer 27

glycosidic bonds formed between hydroxyl groups of two monosaccharides result in the formation of a disaccharide. Most common are sucrose, lactose and maltose

Question 28

lactose

Answer 28

galactose-beta-1,4-glucose

Question 29

maltose

Answer 29

glucose-alpha-1,4-glucose

Question 30

polysaccharides

Answer 30

long chains of monosacchairides linked togetehr by glycosidic bonds

Question 31

heteropolysaccharides

Answer 31

different ypes of monosaccharides

Question 31

homopolysaccharides

Answer 31

same type of monosaccharides

Question 31

starches

Answer 31

They are linked alpha-d-glucose monomers.

Plants store starch as amylose, a linear glucose polymer via alpha-1,4 glycosidic bonds. Another types is amylopectin, which has alpha-1,4 glycosidic bonds and branches with alpha-1,6 glycosidic bonds.

betha-amylase: cleaves anylose at the nonreducing end of the polymer. Yield maltose.

alpha-amylase: cleaves randomly along the chain to yield shorter chains

Question 32

cellulose

Answer 32

beta-d-glucose molecules linked by beta-1,4 glycosidic bonds, with hydrogen bonds holding the polysaccharides together

Question 33

glycogen

Answer 33

storage unit in animals

it has more alpha-1,6 glycosidic bonds, it is th emost branched compound It makes it more soluable in solution, thereby allowing more glucose to be stored in the body. Glycogen phosphorylase is an enzyme that functions by cleaving glucose from the ninreducinf end of a glycogen branch and phosphorylating it, thereby producing glucose 1-phosphate, which plays a important role in metabolism.