CarbohydratesCarbohydrates

Objectives• Distinguish among proteins, carbohydrates, lipids

and nucleic acids. (SPI 3210.1.3) – Identify or describe the skeleton structure of carbohydrates.– Identify the most metabolically important carbohydrate.– Identify and describe the carbohydrate form used to store

excess energy resources in plants, animals and fungi.– Identify the major carbohydrate polymers and their

respective biological functions.– Explain the biochemical processes that form polymers of

simple sugars.• Identify positive tests for carbohydrates, lipids and

proteins (SPI 3210.1.4)– Describe the biochemical test to detect simple sugars and

starch

Mono-, di-, and poly- saccharides(Sugars)

CARBOHYDRATES

Carbohydrate Skeleton Structure

Have the general formula:(CH2O)n

“Carbonated Water”

Simple sugars with a backbone of three to seven carbon atoms.

Best known monosaccharides sugars have six carbons (hexoses).

GlucoseFructoseGalactose

Monosaccharides(Single Sugars)

Dissacharides(Double Sugars)

Two monosaccharide (single sugars) joined by dehydration synthesis. -Lactose Galactose + Glucose

Found in milk.-Maltose Glucose + Glucose

Forms in human digestive tract during starch digestion.-Sucrose Glucose + Fructose

Transported within plants.

Polysaccharides

Chains of glucose molecules or modified glucose molecules.

Polysaccharides(carbohydrates) Used For Energy Storage

Starch.Found in plants.Straight chain of glucose moleculesFew side branches.

Glycogen.Found in animals (called “animal starch”).Highly branched polymer of glucoseMany side branches

Cellulose - Primary constituent of plants cell walls; Not easily digested;.

– Grazing animals can digest cellulose due to special stomachs and bacteria.

– Cotton - nearly pure cellulose.

Chitin - Found in exoskeleton of animals like lobsters and insects; Polymer of glucose with amino acid attached to each.

Polysaccharides(carbohydrates) Structural Forms

Chitin(carbohydrates) Structural Forms

Modified form of cellulose

Test for Simple Sugars

Benedict’s Reagent + Heat (boiling)Positive = Brick Red/Orange

Lugol’s Iodine

Test for Starch

Review• Describe the skeleton structure of

carbohydrates.• What is the most metabolically important

carbohydrate?• Describe the carbohydrate form(s) used to

store excess energy resources in plants, animals and fungi.

• Identify the major carbohydrate polymers and their respective biological functions.

• How are polymers made from simple sugars.