L3: Carbohydrates

CARBOHYDRATES

CARBOHYDRATES

Major source of energy from our diet.

C, H, and O

CARBOHYDRATES Composed of the elements: ____________

saccharides

CARBOHYDRATES is also known as ___________

sugar

saccharides means ____________

CARBOHYDRATES

Produced by photosynthesis in plants.

CARBOHYDRATES

Are oxidized in living cells (respiration) to produce CO2, H20, and energy.

CARBOHYDRATES

“Hydrate of carbon”.

CARBOHYDRATES

Derived from the formula Cn(H2O)m

Glucose

C6H12O6 or C6(H2O)6

CARBOHYDRATES

Provides energy.

Glycogen

provides short term energy reserves.

CARBOHYDRATES

Supply carbon for synthesis of other biochemical substances.

CARBOHYDRATES

Part of the structure of DNA and RNA

CARBOHYDRATES

Linked to lipids – in cell membrane.

CARBOHYDRATES

Linked to proteins – in biological recognition processes

CARBOHYDRATES

Regulation of blood sugar.

CARBOHYDRATES

Spare the use of protein for energy

CARBOHYDRATES

Breakdown of fatty acids and preventing ketosis.

CARBOHYDRATES

Provide flavor and sweetness.

CARBOHYDRATES

Source of dietary fibers

Superimposable Mirror Images

coincide at all points when images are laid upon each other

Nonsuperimposable Mirror Image

not all points coincide when images are laid upon each other.

Chiral Center

Atom in a molecule that has four different tetrahedrally bonded to it.

TRUE

Mirror images are NOT superimposable

T/F

Isomers

compounds possessing identical molecular formulas but different structures

Geometric

Isomers differ in their spatial arrangement about a double bond

Optical

Isomers differ in the arrangement of atoms in 3D space which create mirror images of each other

Structural Isomers

same molecular formula but differ from each other by having different structures.

Stereoisomerism

same molecular formula and same structure but differ in configuration.

Stereoisomerism

differ in arrangement of their atoms in space.

Stereoisomerism

presence of chiral centers allows for the formation of stereoisomers.

D and L, Optical, Epimerism, α and β anomerism.

Types of Stereoisomerism Associated with Glucoses:

Enantiomers

molecules are nonsuperimposable mirror images of each other.

Diastereomers

molecules are not mirror images of each other.

Optical Isomerism

optical activity is the capacity of a substance to rotate the plane polarized light passing through it.

Dextrorotatory(d) or (+)

Optical Isomerism

Clockwise direction

Levorotatory(l) or (-)

Optical Isomerism

Counterclockwise direction

chiral compounds

______________ rotate polarized light clockwise or counterclockwise through a certain angle.

Epimerism

if two monosaccharide differ from each other in their configuration around a single specific carbon (other than anomeric) atom

Anomerism

isomers obtained from the change of position of hydroxyl group attached to the anomeric carbon e.g. α and β glucose are 2 anomers.

Anomerism

Also α and β fructose are 2 anomers

Mutarotation

the change in the specific optical rotation by the interconversion of α and β forms of D glucose to an equilibrium mixture.

Monosaccharide

simplest carbohydrates

Disaccharides

2 monosaccharides

Oligosaccharides

2-10 monosaccharides

Polysaccharides

many monosaccharides

3-6

MONOSACCHARIDE typically consists of __________ carbon atoms

MONOSACCHARIDE

A carbonyl group (aldehyde or ketone)

MONOSACCHARIDE

Several hydroxyl groups.

MONOSACCHARIDE

Colorless, crystalline solids.

Aldose

Monosaccharides with an aldehyde group.

Triose

With many hydroxyl (–OH) groups: ________________ = 3 C atoms

Tetrose

With many hydroxyl (–OH) groups: __________ = 4 C atoms

Pentose

With many hydroxyl (–OH) groups: _____________ = 5 C atoms

Hexose

With many hydroxyl (–OH) groups: _____________ = 6 C atoms

Ketose

Monosaccharides with a ketone group.

D-glucose

Found in fruits, corn syrup, and honey.

D-glucose

An aldohexose with the formula = C6H12O6

D-glucose

Known as blood sugar in the body

D-glucose

The monosaccharide in polymers of starch, cellulose, and glycogen.

70-90

In the body, glucose has a normal blood level of ________ mg/dL/

Glucose Tolerance Test

measures blood glucose for several hours after ingesting glucose.

D-fructose

Is a ketohexose = C6H12O6

D-fructose

The sweetest carbohydrate

D-fructose

Found in fruit juices and honey.

D-fructose

Converts to glucose in the body.

D-galactose

An aldohexose = C6H12O6

D-galactose

Not found free in nature.

D-galactose

Obtained from lactose, a disaccharide.

D-galactose

A similar structure to glucose except for the –OH on C4.

Fischer Projection

Straight chain structural formula

Haworth Projection

Cyclic formula or ring structure.

X-ray Diffraction Analysis

Boat and chair form

Hermann Emil Fischer (German)

Fischer Projection - Developed by __________________________

Fischer Projection

Used to represent carbohydrates.

Fischer Projection

Places the most oxidized group at the top

Fischer Projection

Shows chiral carbons as the intersection of vertical and horizontal lines

Walter Norman Haworth (British).

Haworth Projection - Developed by ___________________

Haworth Projection

Two-dimensional structural annotation that specifies the three-dimensional structure of a cyclic form of monosaccharide.

Cyclic Structures

The prevalent form of monosaccharides with 5 or 6 carbon atoms

Cyclic Structures

Formed when the hydroxyl group on C5 reacts with the aldehyde or ketone group.

DISACCHARIDES

Glycosides formed by the condensation of 2 simple sugars.

non-reducing

If the glycosidic linkage involves the carbonyl groups of both sugars (sugars) the resulting disaccharide is _________

reducing

If the glycosidic linkage involves the carbonyl group of only one of the 2 sugars (as in maltose and lactose) the resulting disaccharide is _____________.

Maltose

Known as “malt sugar”

Maltose

Composed of 2 D-glucose molecules.

Maltose

Obtained from the hydrolysis of starch.

Maltose

Linked by an α-1,4-glycosidic bond formed from the α –OH on C1 of the first glucose and –OH on C4 of the second glucose.

Maltose

Used in cereals, candies, and brewing

Maltose

Found in both the α- and β- forms

Lactose

A disaccharide of β-D-galactose and α- or β-D-glucose

Lactose

Contains a β-1,4-glycosidic bond

Lactose

Found in milk and milk products

Sucrose

“Table sugar”.

Sucrose

Obtained from sugarcane and sugar beets

Sucrose

Consists of α-D-glucose and β-D-fructose.

Sucrose

Has an α, β-1,2-glycosidic bond.

Fructose

sweetest

Fructose

even sweeter than sucrose

Honey

D-fructose and D-glucose