[BIOCHEM LEC MIDTERMS] SUGAR CODES AND GLYCOCONJUGATES

Sugar code

Information carried by the type, shape, arrangement, and connections of sugars

Carbohydrates

Important biomolecules that provide energy and building materials for cells

Glucose

A major carbohydrate that serves as an important source of energy and can also be used to make other biomolecules

Fructose

A simple sugar included among the carbohydrates discussed in the lesson

Starch

A complex carbohydrate used by plants to store glucose and energy

Glycogen

A complex carbohydrate that serves as a major glucose storage form in humans and animals

Cellulose

A complex carbohydrate that serves as an important structural material in plant cell walls

Photosynthesis

The process in which plants use light energy, carbon dioxide, and water to produce glucose and oxygen

Glucose storage in plants

The process in which plants convert excess glucose into starch for storage

Oxidation

A reaction in which an aldehyde is converted into a carboxylic acid in the context of the lesson

Reduction

A reaction in which a carbonyl group is converted into an alcohol

Aldehyde

A functional group that can be oxidized into a carboxylic acid

Carboxylic acid

The functional group produced when an aldehyde group is oxidized

Carbonyl group

The functional group that can be reduced to a hydroxyl group

Hydroxyl group

The –OH group produced when a carbonyl group is reduced

Tollens and benedicts soln

A weak oxidizing agent that oxidizes the aldehyde group of aldose sugars

Gluconic acid

The product formed when glucose is oxidized by a weak oxidizing agent

Galactonic acid

The product formed when galactose is oxidized by a weak oxidizing agent

Strong oxidation

Oxidation that converts both ends of a monosaccharide into carboxylic acid groups

Terminal alcohol group

The end group of a monosaccharide that can be oxidized into a carboxylic acid by a strong oxidizing agent

Dicarboxylic acid

A compound containing two carboxylic acid groups

Aldaric acid

The dicarboxylic acid produced when both ends of a monosaccharide are oxidized

Sugar alcohol

A product formed when the carbonyl group of a monosaccharide is reduced

Alditol

Another name for a sugar alcohol

D-glucitol

The sugar alcohol produced by reduction of D-glucose

Hydrogen

The substance used in the lesson to reduce a monosaccharide’s carbonyl group to a hydroxyl group

Glycoside

A compound that is an acetal formed when the –OH group of a cyclic monosaccharide is replaced by an –OR group

Phosphate ester

An ester formed when a sugar –OH group reacts with an acid, especially a phosphate group

Phosphate ester formation

The reaction in which sugar –OH groups react with acids to form esters

Amino sugar

A sugar in which an –OH group is replaced by an –NH₂ group

C2 amino sugar

The common natural amino sugar arrangement in which the OH at carbon 2 is replaced by NH₂

N-acetylglucosamine

An N-acetyl amino sugar important in polysaccharides and found on red blood cells

N-acetylgalactosamine

An N-acetyl amino sugar found on red blood cells that helps determine blood types

N-acetyl forms

Modified amino sugars that are important components of polysaccharides such as chitin and hyaluronic acid

Acetyl group

The chemical group shown in the lesson as part of N-acetyl amino sugars

Chitin

A polysaccharide containing important amino sugar derivatives and providing strength and rigidity to arthropod exoskeletons

Hyaluronic acid

A polysaccharide containing N-acetyl amino sugar derivatives and important in connective and structural functions

Glycosidic linkage

Another term for the C–O–C bond connecting monosaccharides

Anomeric carbon

The carbon containing the hemiacetal group that can participate in glycosidic bond formation

Acetal carbon

The carbon in a disaccharide formed when the anomeric OH participates in a glycosidic bond

Disaccharide

A carbohydrate formed by joining two monosaccharides through a glycosidic bond

Maltose

The malt sugar formed from two D-glucose units, with one unit being α-D-glucose

Malt sugar

Another name for maltose

starch breaks down during digestion or seed germination

Maltose formation?

Maltose structure

A disaccharide consisting of two D-glucose units, one of which must be α-D-glucose

Malted foods and baby food

Where is maltose found?

Cellobiose

A disaccharide formed when cellulose breaks down

Cellobiose

A disaccharide consisting of two D-glucose molecules with a β-glucose unit

B 1→4

The ____ glycosidic linkage found in cellobiose

Lactose

A disaccharide made of galactose + glucose joined by a β(1→4) glycosidic linkage

Reducing sugar

A sugar with a free anomeric carbon that can retain an open-chain form

Lactase

The enzyme that breaks lactose into glucose and galactose

Lactic acid

The acid produced when bacteria convert lactose and contribute to milk souring

Sour milk

The result of bacteria converting lactose into lactic acid

Sucrose

A disaccharide classified as a nonreducing sugar because both anomeric carbons participate in the glycosidic bond

Nonreducing sugar

A sugar whose anomeric carbon cannot open into an open-chain form because it is involved in the glycosidic bond

a/b

The forms that sucrose does not have because both anomeric carbons participate in the glycosidic bond

Sucrase

The enzyme that breaks sucrose into glucose and fructose

Invert sugar

The mixture produced when sucrase breaks sucrose into equal amounts of glucose and fructose

a(1→6) glycosidic linkage

A linkage connecting C1 of one α-D-glucose to C6 of another glucose

Oligosaccharide

A carbohydrate containing a small number of monosaccharide units

Raffinose

An oligosaccharide containing galactose + glucose + fructose, for a total of three sugars

Stachyose

An oligosaccharide containing four sugars, with an extra galactose compared with raffinose

Polysaccharide

A large carbohydrate made of many monosaccharides joined by glycosidic bonds

Glycan

Another term for a polysaccharide

Homopolysaccharide

A polysaccharide made of only one type of monosaccharide

Heteropolysaccharide

A polysaccharide made of two or more types of monosaccharides

Starch

A homopolysaccharide made only of glucose

Plant glucose storage

The role of starch

Amylose

The unbranched component of starch comprising about 15–20%

Amylopectin

The branched component of starch comprising about 80–85%

15-20%

The approximate proportion of starch represented by amylose

80-85%

The approximate proportion of starch represented by amylopectin

a 1→4

The ___ glycosidic bond found in amylose

Glycogen composition

A polysaccharide made only of glucose

Animal glucose storage

The role of glycogen

liver and muscle

The ____ are the main storage sites for glycogen

Cellulose

An unbranched polymer of glucose with β(1→4) glycosidic linkages

structural material in plant cell walls

The role of cellulose

cellulose

The fact that ___ is the most abundant natural polysaccharide

stems, stalks, trunks

Cellulose is found in high amounts in ___ (3)

Chitin

The fact that ____ is the second most abundant natural polysaccharide

strength and rigidity to exoskeletons of arthropods

The role of chitin

fungi

The presence of chitin in the cell walls of __

D-glucuronic acid

A sugar acid formed when the –CH₂OH group of glucose is oxidized to –COOH

Hyaluronic acid

A polysaccharide made of repeating disaccharide units with alternating β(1→3) and β(1→4) glycosidic bonds

50k

A hyaluronic acid chain that can contain about ___ disaccharide units

lubricating joints

The role of hyaluronic acid

Vitreous humor

The jelly-like substance in the eye whose consistency is supported by hyaluronic acid

Heparin

A highly sulfated polysaccharide made of repeating disaccharide units

Heparin

A polysaccharide composed of repeating disaccharide units with negatively charged sugar components

Natural anticoagulant

A substance that helps prevent blood clot formation

natural coagulant

The role of heparin as a ______ that prevents blood clots from forming and slows existing clot growth

does not

The fact that heparin ____ dissolve existing clots (does/does not)

Mast cells

The cells in which natural heparin is found

dialysis machines, test tubes, medical implants

The use of heparin to prevent blood clotting in ____ (3)

pig and cow tissues

The source of medical heparin commonly obtained from ___

Glycoconjugate

A molecule formed when a carbohydrate is attached to another type of molecule, such as a protein or lipid

Glycolipid

A glycoconjugate consisting of a lipid + carbohydrate

Glycoprotein

A glycoconjugate consisting of a protein + carbohydrate