LE2_Carbohydrate Structure, Funtion and Digestion Flashcards by Hazel Ayala

are polyhydroxylated aldehydes and ketones and substances that yield such compounds upon hydrolysis

carbohydrates

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Functions of carbohydrates

as energy source

as part of the structural framework

as structural elements in cell walls

as part of nucleic acids and some lipids and proteins

as units on cell surfaces for cell-to-cell recognition processes

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Major classes of carbohydrates

Monosaccharides (simple sugars)

Disaccharides (2 monosaccharides)

Oligosaccharides (3-10 monosaccharides)

Polysaccharides (long chains of monosaccharides)

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single polyhdroxylated aldehyde or ketone unit

Monosaccharide (simple sugar)

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consist of two monosaccharides linked together by a glycosidic bond

Disaccharides

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carbohydrates made up of 3-10 monosaccharide units

Oligosaccharides

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long chains of monosaccharide units

Polysaccharides

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Can a monosaccharide be hydrolyzed further into simpler units?

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general formula for monosaccharides

(CH2O)n

n-number of carbons present in the structure

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how many carbons are present in the simplest monosaccharide sugars?

n=3

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Simplest monosaccharide

aldotriose & Ketoriose

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Example of aldotriose

Glyceraldehy

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Example of ketotriose

Dihydroxyacetone

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What class of carbohydrates does glyceraldehyde belongs to?

Monosaccharides (Aldotriose)

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What carbonyl group is present in Dihydroxyacetone

Ketose (Ketotriose)

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Draw the structure of glyceraldehyde (an aldotriose)

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Draw the structure of Dihydroxyacetone (a ketotriose)

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How are monosaccharides classified?

Based on carbonyl group present:

aldose

ketose

Based on the number of carbon atoms:

Triose

Tetrose

Pentose

Hexose

Heptose

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Classification of monosaccharides based on the carbonyl group present

Aldose

Ketose

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Classification of monosaccharides based on the number of carbon atoms

Triose

Tetrose

Pentose

Hexose

Heptose

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If you were tasked to classify the given monosaccharides, where would you classify each of them?

D-Glucose

D-Fructose

D-Ribose

2-Deoxy-D-Ribose

Aldohexose

Ketohexose

Aldopentose

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In Stereochemistry, which among all monosaccharides is the only not optically active?

Dihydroxyacetone

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Are all monosaccharides optically active?

No, Dihydroxyacetone is an exemption

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In stereochemistry, what is the relative configuration of a monosaccharide if its hydroxyl (-OH) group is at the right of the penultimate carbon?

D-

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In stereochemistry, what is the relative configuration of a monosaccharide if its hydroxyl group (-OH) is at the left of the penultimate carbon?

L-

What does penultimate carbon means?

2nd to last carbon in a carbon chain

Identify the structure and determine its relative configuration

D-Glyceraldehyde

Identify the structure and determine its relative configuration?

L-Glyceraldehyde

How would you determine the number of stereoisomers of a certain monosaccharide?

2^n (superscript) n=number of chiral centers

What are chiral centers of chiral carbons?

are carbons that is bonded to four different substituents or groups (non-superimposable mirror images, enantiomers)

How many stereoisomers can be formed among aldotriose sugars?

2 stereoisomers only (D- and L-Glyceraldehyde for instance)

How many stereoisomers can be formed in an aldotetrose sugar?

4 stereoisomers (D- and L-Erythrose, D- and L-Threose

Examples of aldotetrose monosaccharides

Erythrose and Threose

What type of class of sugar is D-Erythrose?

Aldotetrose

Draw the structure of D-Threose

Draw the structure of D-Erythrose

How many stereoisomers can be formed from aldopentose?

8 stereoisomers (Ribs Are Xtra Lean)

Examples of Aldopentoses

Ribs Are Xtra Lean Ribose Arabinose Xylose Lyxo

How many stereoisomers can be formed form Aldohexose?

16 stereoisomers (All Altruist Gladly Make Gum In Gallon Tanks)

Examples of Aldohexose

All Altruist Gladly Make Gum In Gallon Tanks Allose Altrose Glucose Mannose Gulose Idose Galactose Talo

How many stereoisomers can be formed in Ketohexoses

8 stereoisomers (PeFect SuiTor)

How many stereoisomers can be formed from Ketopentose?

4 stereoisomer

Examples of Ketopentose

Ribulose and Xylulos

Examples of Ketohexoses

PerFect SuiTor Psicose Fructose Sorbose Tagatose

sugars that differ in configuration in only one carbon other than the penultimate carbon

Epimers

Epimers of D-glucose

D-Mannose and D-Galactose

D-mannose is an epimer of D-glucose at what carbon?

Carbon 2

D-Galactose is an epimer of D-Glucose at what carbon?

Carbon 4

Draw the structure of D-Ribose

Draw the structure of D-Arabinose

Draw the structure of L-Xylose

Note: just change the orientation of the groups attached in the penultimate carb

Draw the structure of L-Lyxose

Note: just change the orientation of the groups attached in the penultimate carbon

Draw the structures of D-Allose

Draw the structure of L-Idose

Note: just change the orientation of the groups attached in the penultimate carbon

Draw the structure of D-Ribulose

Draw the structures of D-Xylulose

Draw the structure of D-psicose

Draw the structure of L-Sorbose

Note: just change the orientation of the groups attached in the penultimate carbon

What cyclic structure is formed when alcohol group forms a bond with an aldehyde group?

Hemiacetal

What cyclic structure is formed when alcohol group forms a bond with a ketone group?

Hemiketal

Stereoisomers that differ in configuration at the anomeric carbon

Anomers

A process involved in the conversion of anomers

Mutarotation

What are the three forms of sugar structures that are in equilibrium in aqueous solution?

Linear Form Cyclic Form Anomeric form

What does anomeric carbon means?

A carbon that was previously part of the carbonyl group in the linear open-chain form and participate in the formation of the cyclic structures

Draw the anomeric structure of B-D-glucopyran

Draw the structure of a-D-glucopyranose

What is the anomeric form of a sugar if the -OH group at anomeric carbon is Cis to the -CH2OH group?

B-anomer

What is the anomeric form of a sugar if the -OH group at anomeric carbon is trans to the -CH2OH group?

a-anomer

sugars that are able to undergo oxidation coupled with a reduction of another substance

Reducing sugar

Is glucose a reducing sugar?

Yes

Examples of reducing sugars

D-Fructose An enediol D-Glucose D-Mann

What is glycoside?

a molecule which the anomeric carbon of a monosaccharide reacts with an -OH of an alcohol to give acetal

Example of a glycosid

Methyl B-D-glucopyranoside

Is methyl B-D-Glucopyranoside a disaccharide?

No, its glycoside

How are disaccharides form?

the anomeric carbon of a monosaccharide reacts with an -OH group that is part of another monosaccharide forming glycosidic bond

What is the disaccharide scientific name of lactose?

O-B-D-Galactopyranosyl-(1-4)-a-D-Glucopyranose

Draw the structure of O-B-D-Galactopyranosyl-(1-4)-a-D-Glucopyranose (Lactose)

Examples of disaccharides and its monosaccharide units

Lactose (Galactose and Glucose) Sucrose (Glucose and Fructose) maltose (2 Glucose) Trehalose (2 Glucose) Cellobiose (2 Glucose)

Milk sugar

Lacto

Is lactose a reducing sugar?

yes, free anomeric carbon at a-D-Glucopyranose

Glycosidic bond present in Lact

B-1, 4

Disaccharide Sugar used in brewing beer

Maltose (reducing)

glycosidic bond present in maltose

a-1, 4

What is the disaccharide scientific name of Maltose?

O-a-D-glucopyranosyl-(1-4)-a-D-glucopyranose

Draw the structure of maltose (O-a-D-Glucopyranosyl-(1-4)-a-D-Glucopyranose)

Example of non-reducing sugar

Sucrose (common table sugar)

Glycosidic bond present in sucrose

a-1, B-2

What is the disaccharide scientific name of sucrose?

O-a-D-glucopyranosyl-(1-2)-b-D-fructofuranoside

Draw the structure of sucrose (O-a-D-glucopyranosyl-(1-2)-B-D-fructofuranoside

Depending on the type of monosaccharide repeating units, polysaccharide can be?

homopolymers heteropolymers

a polysaccharide with only one type of monosaccharide as repeating unit

Homopolymer

a polysaccharide with more than one type of monosaccharide which are linked together

heteropolymer

Examples of polysaccharide

Cellulose Chitin starch Glycogen Hyaluronic acid Carrageenan

what glycosidic bond is present in the cellulose?

B-1, 4

is cellulose heteropolymer or homopolymer?

Homopolymer

What is the monosaccharide unit of cellulose?

Glucose

major component of plant cell wall

cellulose

major storage form of carbohydrates in plants

starch

what glycosidic bond is present in starch?

a-1, 4 (between glucose), a-1, 6 (

What polysaccharide comr

Amyl

What are the monosacchari

Glucos

What is the glycosidic bond present in amylose?

a-1,4

What glycosidic bond is present in amylopectin?

a-1, 6

Is starch a heteropolymer or homopolymer?

Homopolymer

major storage form of carbohydrates in animals and fungi

glycogen

is glycogen heteropolymer or homopolymer?

Homopolymer (glucose, highly branched amylopectin)

N-containing polysaccharide which is the major component of exoskeleton of crustaceans (shrimp, crab, lobsters)

Chit

What is the monosaccharide unit of chitin?

NAG (N-acetyl-D-Glucosamine)

Is chitin heteropolymer or homopolymer?

Homopolymer (NAG)

major component of neural, connective and epithelial tissues that functions as shock absorber

Hyaluronic acid

Monosaccharide units of hyaluronic acid

NAG (N-acetyl-D-glucosamine) & D-gluconic acid

Is hyaluronic acid heteropolymer or homopolymer?

Heteropolymer (NAG & D-gluconate)

cell wall material sulfated polysaccharides widely used in the food industry

Carrageenan

Is carrageenan homopolymer or heteropolymer?

Heteropolymer

LE2_Carbohydrate Structure, Funtion and Digestion Flashcards

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