Chapter-7_Carbohydrates

Sialic acid

A complex monosaccharide that is found on the surface of normal cells and some cancer cells; serves as a marker for cell identity.

Carbohydrates

The most abundant class of bioorganic molecules, constituting about 75% by mass of dry plant materials.

Cellulose

A structural carbohydrate in plants that serves as a building material for plant cell walls.

Starch

A storage carbohydrate in plants that provides energy reserves.

Glycogen

A storage form of glucose in animals, highly branched and used for short-term energy reserves.

Monosaccharide

A simple carbohydrate that contains a single polyhydroxy aldehyde or polyhydroxy ketone unit.

Disaccharide

A carbohydrate that consists of two monosaccharide units linked together.

Oligosaccharide

A carbohydrate that contains 3 to 10 monosaccharide units covalently bonded.

Polysaccharide

A polymeric carbohydrate containing many monosaccharide units linked together.

Chirality

The geometric property of a molecule having non-superimposable mirror images.

Aldose

A monosaccharide that contains an aldehyde functional group.

Ketose

A monosaccharide that contains a ketone functional group.

Reducing sugar

A sugar that can act as a reducing agent because it can be oxidized to a carboxylic acid.

Glycoside

An acetal formed from a cyclic monosaccharide by replacement of the hemiacetal carbon -OH group with an -OR group.

Hyaluronic acid

An acidic polysaccharide that serves as a lubricant in joints and has jelly-like consistency.

Heparin

A small highly sulfated polysaccharide that acts as a blood anticoagulant.

Glycolipid

A lipid molecule that has one or more carbohydrate units covalently bonded, involved in cell recognition.

Glycoprotein

A protein molecule that has one or more carbohydrate units covalently bonded; plays a role in cell recognition.

Trioses

are monosaccharides that contain three carbon atoms.

Tetroses

are monosaccharides that contain four carbon atoms.

Pentoses

are monosaccharides that contain five carbon atoms.

Hexoses

monosaccharides that contain six carbon atoms.

Heptoses

are monosaccharides that contain seven carbon atoms.

Sucrose

is a disaccharide composed of glucose and fructose linked by an α-1,2-glycosidic bond.

Lactose

is a disaccharide composed of glucose and galactose linked by a β-1,4-glycosidic bond.

Maltose

is a disaccharide composed of two glucose units linked by an α-1,4-glycosidic bond.

Oligosaccharides

are carbohydrates composed of 3 to 10 monosaccharide units.

Homopolysaccharides, Heteropolysaccharides

____________ consist of one type of monosaccharide, while consist _______________of multiple types.

Homopolysaccharides

Examples include starch, glycogen, and cellulose.

Heteropolysaccharides

Examples include hyaluronic acid and heparin.

Cellulose

provides structural support to plant cell walls.

Starch

is composed of amylose and amylopectin, which are polymers of glucose.

Glycogen

serves as a short-term energy reserve in animal cells.

Glycoproteins

facilitate cell recognition and signaling.

Reducing Sugars

can participate in redox reactions due to their ability to be oxidized.

Disaccharide

is composed of two monosaccharides linked by a glycosidic bond.

Polysaccharides

are made up of multiple monosaccharide units linked together.

Starch, Cellulose

__________ is a storage carbohydrate, while _________ provides structural integrity.

Enantiomers

are pairs of molecules that are non-superimposable mirror images of each other, often related to chirality.

Optical Activity

refers to the ability of chiral compounds to rotate the plane of polarized light.

Racemic Mixture

is a 1:1 mixture of two enantiomers of a chiral molecule.

Oxidation, Reduction

Monosaccharides can undergo __________, __________, and glycosylation reactions.

hydrolysis

Disaccharides can undergo ___________ to yield monosaccharides and can participate in glycosidic bond formation.

cellular signaling

Oligosaccharides can participate in hydrolysis and can be involved in __________ and recognition.

monosaccharides

Polysaccharides generally undergo hydrolysis to release __________ and can also be involved in modifications.

Chirality

can significantly influence the interactions and functions of biochemical

N-acetylneuraminic acid

IUPAC name of sialic acid

Carbohydrates

constitute 75% by mass of dry plant materials

2/3 carbohydrates by mass

average human diet for carbohydrate intake

4 kilocalories of energy

how much energy does each burned gram of carbohydrates release

CnH2nOn

general formula for carbohydrates

molecular size

carbohydrates are classified based on…

Monosaccharides

cannot be broken down into smaller substances by hydrolysis reaction

stereoisomers

same molecular formula and same bonding patterns but differ in the arrangement of atoms in space

chiral carbon

a carbon atom that has 4 different groups bonded to it

nonsuperimposable mirror images

are images where not all of the points coincide when the mirror images are laid upon each other

superimposable mirror images

are images which all of its points coincide

Constitutional Isomers

are isomers that have different connectivity

Skeletal Isomers

isomers with different carbon atom arrangements

Positional Isomers

have different locations of functional groups

Functional Isomers

are isomers that have different functional groups

Diastreoisomers

stereoisomers that are not mirror images of each other

Dextrorotatory compound, clockwise

is a chiral compound that rotates the plane-polarized light in a ________ direction

Levorotatory compound, counterclockwise

is a chiral compound that rotates the plane-polarized light in a ___________ direction

20

The response of the body to the D isomer of the hormone is__ times greater than its response to the L isomer of the hormone

D-Glyceraldehyde and Dihydroxyacetone

two trioses that are important intermediates in the process of glycolysis

Glycolysis

series of reactions that converts 2 glucose molecules to 2 molecules of pyruvate

D-Glucose

found in high amounts in ripe fruits; blood sugar; also known as dextrose

D-Galactose

brain sugar; synthesized from glucose in the body for the production of lactose

D-Fructose

also known as levulose and fruit sugar; sweetest-tasting of all sugars; dietary sugar

D-Ribose

Component of ribonucleic acids (RNAs) and energy-rich compounds such as adenosine triphosphate (ATP).

two cyclic structures

monosaccharides containing five or more carbon atoms, such open-chain structures are actually in equilibrium with….

Oxidation

reaction that will convert primary alcohol to aldehyde to carboxylic acid

Reduction

reaction that will convert aldehyde to primary alcohol

Aldonic Acid

Tollens and Benedict’s solutions, oxidize the aldehyde end of an aldose to give an

brick-red precipitate

Benedict’s solution gives a ___________ with reduced sugars; indicates a positive result

Strong oxidizing agents, dicarboxylic acids

can oxidize both ends of a monosaccharide at the same time (the carbonyl group and the terminal primary alcohol group) to produce a _________

Aldaric

Such polyhydroxy dicarboxylic acids are known as

primary alcohol; alduronic acid

biochemical systems enzymes can oxidize the ________ end of an aldose such as glucose, without oxidation of the aldehyde group, to produce an________

Hydrogen

The carbonyl group present in a monosaccharide (either an aldose or a ketose) can be reduced to a hydroxyl group, using ______ as the reducing agent.

Alditols

polyhydroxy alcohols

Glycoside

is an acetal formed from a cyclic monosaccharide by replacement of the hemiacetal carbon -OH group with an -OR group

Phosphoric Acids

Phosphate esters, formed from _________ and various monosaccharides, are commonly encountered in biochemical systems

Oxygen Bridge

Disaccharides consist of two monosaccharides joined through an “______________.”

Glycosidic Linkage

is the bond between two monosaccharide

Malt

germinated barley that has been baked and ground

Maltose

produced whenever the polysaccharide starch breaks down

Maltase

the enzyme that breaks the glucose–glucose α(1→4) linkage present in maltose, is found both in the human body and in yeast

Cellubiose

an intermediate in the hydrolysis of the polysaccharide cellulose

Lactose

major sugar found in milk

Scandinavians and Northern Europeans

Lactose intolerance is lowest among _______ and ______

North America, Southeast Asia, Africans, and Greek

Lactose Intolerance is highest among ______, _____, ______, ______

60%

percentage of majority in which are lactose intolerant

Lactic Acid

Bacterial fermentation of the lactose further along the intestinal tract produces

Sucrose

common table sugar; is the most abundant of all disaccharides and occurs throughout the plant kingdom.

Invert Sugar

When sucrose is cooked with acid-containing foods such as fruits or berries, partial hydrolysis takes place, forming some ______

Honeybees, invertase

______ and many other insects possess the enzyme ____-_