BI108 Carbohydrates & Lipids

Macromolecules

molecules that make up living organisms

Functional groups:

groups of atoms with particular properties

Hydroxyl group

polar

Methyl group

nonpolar

Carbonyl group

polar

Sulfhydryl group

polar

Carboxyl group

• charged

• ionizes to release H+

• acidic

Amino group

• charged

• accepts H+ to form NH3+

• basic

Phosphate group

• charged

• ionizes to release H++

• acidic

Condensation reaction (dehydration synthesis)

removing water and making a bond

Hydrolysis reaction

inputting water and breaking a bond

Carbohydrate

source of stored energy within plants and animals

Monosaccharide

simple sugars; “one sugar”

Disaccharides

“two sugars” linked by covalent bonds

Oligosaccharides

medium-sized polymers; 3-20 monosaccharides

Polysaccharides

“many sugars”; hundreds or thousands of monosaccharides

Glycosidic linkages

a covalent bond that connects a carbohydrate molecule to another molecule; formed by condensation reactions (H2O is a product)

Alpha (ɑ) glycosidic linkages

Bent, branched

Relatively easy to break

Glycogen

storage of glucose in animals

Starch

storage of glucose in plants

Beta (β) glycosidic linkages

Linear

Hydrogen bonding makes it relatively hard to break

Cellulose

very stable, good for structural components, found in plants

Chitin

structural support and protection that forms the exoskeleton of arthropods (insects, crustaceans), the cell walls of fungi, and various hard structures in invertebrates

Glycan

polymers of simple sugars bonded with glycosidic linkages

Hydrocarbon chains

chains that consist of hydrogen and carbon atoms

Fats

important in energy processing and storage

Glycerol

has three hydroxyl groups, serving as the backbone of triglycerides

Fatty acid

nonpolar hydrocarbon with a polar carboxyl group (-COOH)

Saturated fatty acid

when all C-C bonds are single bonds; long straight chain

Unsaturated fatty acid

contains C=C bonds that are double bonds; introduces bends in the structure

Ester bond

when carboxyls interact with hydroxyls of glycerol

Steroids

a lipid containing carbon atoms arranged in four “fused rings”

Phospholipids

phosphate-containing compound, glycerol, 2 fatty acid chains

• hydrophilic head

• hydrophobic tail

Amphipathic molecules

molecules that have hydrophilic and hydrophobic regions; opposing chemical properties