Carbohydrates

Question 1

What is the most basic structural unit of carbohydrates?

Answer 1

monosaccharides

Question 2

What is the simplest monosaccharide?

Answer 2

trioses

Question 3

What are aldoses?

Answer 3

carbohydrates that contain an aldehyde group as their most oxidized functional group

Question 4

What are ketoses?

Answer 4

carbohydrates that contain a ketone group as their most oxidized functional group

Question 5

Structure of D-fructose

Answer 5

google it

Question 6

Structure of D-glucose

Answer 6

google it

Question 7

Structure of D-galactose

Answer 7

google it

Question 8

Structure of D-mannose

Answer 8

google it

Question 9

What are stereoisomers?

Answer 9

compounds that have the same chemical formula but differ in spatial arrangement of atoms

Question 10

What are enantiomers?

Answer 10

stereoisomers that are non-identical, nonsuperimposable mirror images of each other

Question 11

Equation for number of stereoisomers

Answer 11

2^n

Question 12

What are diasteroemers?

Answer 12

stereoisomers that are non identical and not mirror images

Question 13

What are epimers?

Answer 13

diastereoisomers that differ in configuration at exactly on chiral center

Question 14

What is a six membered ring called?

Answer 14

furanose

Question 15

What is a five membered ring called?

Answer 15

pyranose

Question 16

What is an alpha -anomer?

Answer 16

when the -OH group of C-1 is trans to the CH2OH group (axial and down)

Question 17

What is a beta-anomer?

Answer 17

when then -OH group of C-1 is cis to the CH2OH group (equatorial and up)

Question 18

What is mutarotation?

Answer 18

spontaneous change of configuration about C-1 and is catalyzed with acid or base; results in a mixture of both alpha and beta anomers

Question 19

What are aldonic acids?

Answer 19

oxidized aldoses

Question 20

What are lactones?

Answer 20

a cyclic ester with a carbonyl group

Question 21

What are two reagents used to test the presence of a reducing sugar?

Answer 21

Tollen’s reagent and Benedict’s reagent

Question 22

What is Tollen’s reagent?

Answer 22

silver nitrate + NaOH –> silver oxide + ammonia –> Tollen’s reagent

Question 23

How does Benedict’s reagent work?

Answer 23

aldehyde group of aldose is readily oxidized and a red precipitate is formed

Question 24

What is tautomerization?

Answer 24

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

Question 25

What is an enol?

Answer 25

a compound with a double bond and alcohol group

Question 26

What is an alditol?

Answer 26

when the aldehyde group of an aldose is reduced to an alcohol

Question 27

What is a deoxy sugar?

Answer 27

contains a hydrogen that replaces a hydroxyl group on the sugar

Question 28

What is phosphorylation of glucose?

Answer 28

metabolic reaction of glycolysis in which a phosphate group is transferred from ATP to glucose, thus phosphorylating glucose while forming ADP

Question 29

What is the difference between esterification and glycoside formation?

Answer 29

Esterification is the reaction by which a hydroxyl group reacts with either a carboxylic acid or a carboxylic acid derivative to form an ester; glycoside formation refers to the reaction between an alcohol and a hemiactal/ketal group on a sugar to yield an alkoxy group

Question 30

Do carbs get oxidized or reduced?

Answer 30

oxidized

Question 31

What is a disaccharide?

Answer 31

glycosidic bonds formed between hydroxyl groups of two monosaccharides

Question 32

Structure of sucrose

Answer 32

google it

Question 33

Structure of lactose

Answer 33

google it

Question 34

Structure of maltose

Answer 34

google it

Question 35

What are polysaccharides?

Answer 35

long chains of monosaccharides linked together by glycosidic bonds

Question 36

What is a polysaccharide made entirely of glucose?

Answer 36

homopolysaccharide

Question 37

What is cellulose?

Answer 37

homopolysaccharide - a chain of beta-D-glucose molecules linked by beta-1,4 glycosidic bonds, with hydrogen bonds holding the actual polymer chains together for support

Question 38

What are starches?

Answer 38

polysaccharides that are more digestible by humans because they are linked alpha-D-glucose monomers

Question 39

What is amylose?

Answer 39

linear glucose polymer linked via alpha-1,4 glycosidic bonds (plants store starch as this)

Question 40

What reagent tests for the presence of starch?

Answer 40

iodine

Question 41

What does beta-amylase do?

Answer 41

cleaves amaylose at the nonreducing end of the polymer (the end with the acteal) to yield maltose

Question 42

What does alpha-amylase do?

Answer 42

cleaves randomly along the chain to yield shorter polysaccharide chains, maltose and glucose

Question 43

What is glycogen?

Answer 43

carbohydrate storage for animals -

Question 44

What is glycogen phosphorylase?

Answer 44

functions by cleaving glucose from the nonreducing end of a glycogen branch and phosphorylating it, thereby producing glucose 1-phosphate