Carbohydrates

furan

5-membered ring containing one O atom

What are the 10 major basic sugars?

6 aldoses, 4 ketoses aldoses: glyceraldehyde, erythrose, ribose, glucose, galactose, mannose ketoses: dihydroxyacetone, ribulose, xylulose, fructose all are in the D-conformation where applicable

pyran

6-membered ring containing one O atom

monosacchs. that have the same number of carbons but differ in content of either an aldehyde or ketone are:

isomers they still have the same chemical formula

fructose

ketohexose hydroxyl configuration: left, right, right

xylulose

ketopentose hydroxyl configuration: left, right

ribulose

ketopentose hydroxyl configuration: right right

What are the major naturally occurring disaccharides?

maltose, lactose, and sucrose

starch

mixture of amylose and amylopectin main storage form of plants

carbohydrate

molecule that contains multiple alcohol, ketone, and/or aldehyde groups

epimers

molecules that have identical configurations of their multiple chiral centers to each other except at one chiral center

diastereomers

molecules that have multiple chiral centers and are similar in configurations but differ at more than one chiral center

monosaccharide

monomeric unit of carbs, has formula Cn(H20)n, where n is greater than 3

ketose

monosacch. with a ketone group

aldose

monosacch. with an aldehyde group

furanose

monosaccharide converted into a five-membered ring

pyranose

monosaccharide converted into a six-membered ring

largest naturally occuring monosacch.

nonoses (9 carbs)

mutorotation

rapid change from open chain to cyclic system

aldonic acid

results from oxidation of aldose's carbonyl group COH → COOH forms from reaction of a sugar and the oxidizing agents, such as Tollen's and Benedict's

uronic acid

results from terminal carbon of monosacchs. being oxidized C2OH → COOH

Which of the monosacchs. produces furanoses?

ribose and fructose

dextrans

storage form of yeasts and bacteria, very similar to the other forms starch and glycogen component of dental plaque, usually glucans (glucose homopolymers) or levans (fructose homopolymers)

a sugar is in the D-conformation if:

the last chiral carbon's hydroxyl group points to the right in the Fischer projection

carbon names according to #: 3, 4, 5, 6, 7...

triose, tetrose, pentose, hexose, heptose...

disaccharide

two monosaccs. covalently linked

ribulose is an epimer to

xylulose

example of anomers

α-D-mannose and β-D-mannose

about glyceraldehyde, erythrose, and ribose

1. all alcohol groups point to the right 2. glyceraldehyde: 3 carbons, erythrose: 4 carbons, ribose: 5 carbons

Which enantiomeric form of the sugars is used by cells?

D-form (dextro, meaning right side)

the last carbon of the monosaccharides is always:

above the plane of the ring

mannose

aldohexose alcohol group configuration: left, left, right, right

galactose

aldohexose alcohol group configuration: right, left, left, right

glucose

aldohexose all alcohol groups point to the right except for C3 "right, left, right, right"

alpha sugar

anomeric alcohol points down

beta sugar

anomeric alcohol points up

esterification

any hydroxyl on the sugar is bound to a phosphate, sulfat, organic acid via ester linkage

reducing sugar

any sugar that can be oxidized Ex: all the aldoses, which have an aldehyde COH → COOH

How do glucose and mannose differ?

at carbon 2: mannose's OH group points left

How do ribulose and xylulose differ?

at carbon 3: xylulose's alcohol points to the left

How do glucose and galactose differ?

at carbon 4: galactose's OH group points left

glucose is an epimer to:

both galactose and mannose

all of the common ketoses have their ketone groups at:

carbon 2

anomeric carbon

carbonyl carbon in open chain form, hemiacetal carbon in ring form

oligosaccharide

contain 2-20 monosacchs.

polysaccharide

contain more than 20 monosacchs.

anomers

cyclic monosacchs. that differ only in alpha/beta configuration of alcohol group on anomeric carbon.

maltose

derived from broken down starch glucose (α1 → 4) glucose reducing sugar because second glucose molecule has unlocked anomeric carbon, can revert back to reducible aldehyde

stereochemically, galactose and mannose are

diastereomers

Which of the 10 monosacchs. is the only one without a chiral center?

dihydroxyacetone (3 carbs, symmetrical)

glycosidic bond

formed between the anomeric hydroxyl of one cyclic sugar and the hydroxyl group on another sugar bond between di-, oligo-, and polysaccharides

muramic acid

formed when an acetate group is added to amino sugar via amide linkage

deoxy sugar

formed when any hydroxyl on the sugar is reduced CHOH → CH2

sugar alcohol

formed when carbonyl group is reduced to an alcohol Ex: mannitol, xylitol, erythritol (Truvia)

amino sugar

formed when hydroxyl group on carbon #2 of glucose, galactose, and mannose is replaced with amino group glucose → glucosamine

cyclic hemiacetal

forms when an alcohol group of a 5 or 6 carbon-long sugar reacts with the carbonyl carbon of the aldehyde group

cyclic hemiketal

forms when the alcohol group of a 5 or 6 carbon-long sugar reacts with the carbonyl carbon of the ketone group

How many chiral carbons do the three aldohexoses have?

four

the only ketose that forms a ring is

fructose

lactose

galactose (β1 → 4) glucose reducing sugar

glycogen

glucose (α1 → 4) glucose branched polymer, exact same structure as amylopectin and amylose, except it branches out every 8-12 units at branch points, glycosidic bond is α1 → 6 main storage form of mammals

amylopectin

glucose (α1 → 4) glucose branched polymer, exact same structure as amylose except it branches out every 24-30 units at branch points, glycosidic bond is α1 → 6

amylose

glucose (α1 → 4) glucose linear polymer

sucrose

glucose (α1 ↔ β2) fructose glucose stacked over fructose anomeric hydroxyls of both sugars bound to each other, therefore this disacch. is locked in position and is not a reducing sugar

cellulose

glucose (β1 → 4) glucose linear homopolymer, very strong, very few organisms can hydrolyze this glycosidic bond

galactose is an epimer to

glucose only

mannose is an epimer to

glucose only

Which of the monosacchs. forms pyranoses?

glucose, galactose, and mannose

the simplest monosacchs.

glyceraldehyde and dihydroxyacetone (both 3 carbs long)