Carbohydrates (sugars) Classified based on # of simple sugars C H O in 1:2:1 ratio Major nutrients for cells; ie glucose Produced by photosynthetic organisms Store energy in chemical bonds C skeletons raw materials for other organic compounds

Carbohydrates-disaccharides Disacch.Monomers Maltoseglu + glu Lactoseglu + galac Sucroseglu + fru

Carbohydrates: Polysaccharides 2 Important biological functions: –Energy storage (starch, glycogen) –Structural support (cellulose, chitin)

Storage Polysaccharides Starch = glucose polymer, for energy storage in plants –Helical glucose polymer –Most animals have enzymes to hydrolyze it –Major sources in human diet are potatoes and grains

Storage Polysaccharides Glycogen = glucose polymer, for energy storage in animals Branched molecule Stored in muscle and liver of humans and other vertebrates

Structural Polysaccharides Cellulose = linear unbranched polymer –Major structural component of plant cell walls –Differs from starch in its monomer linkage –Cannot be digested by most organisms

Structural Polysaccharides Chitin = structural polysacch.; a polymer of an amino sugar (nature’s plastic) Forms exoskeleton of Arthropods Found as cell walls in fungi

Lipids Diverse group of organic compounds that are insoluble in water Includes animal fats, plant oils, steroids, phospholipids Made of fatty acids and glycerol

Fat Saturated All single bonds Solid at room temp Animal fats Unsaturated One or more double bonds between carbons Liquid at room temp “Vegetable” or plant oils

Useful functions of fat Energy storage More compact fuel reserve than carbo. Cushions vital organs in mammals Insulates against heat loss

Phospholipids Component of cell membranes (bilayer) 2 fatty acids & phosphate group Amphipathic behavior in water

Steroids Lipids w/ 4 fused carbon rings and various functional groups Cholesterol important as precurser to other steroids; and enhance membrane fluidity

Proteins Complex polymers of amino acids Abundant: make up 50% or more of dry wt Varied functions in cell: structure, metabolism, transport, signaling, movement, defense Each has unique 3-D shape Made of only 20 different amino acids

Amino Acid Structure

Nucleic Acids Deoxyribonucleic Acid (DNA) Can replicate itself and be passed from one generation of cells to the next Genes are segments of DNA that code for protein Ribonucleic Acid (RNA) Functions as mediator between genotype and phenotype 3 functional forms carry out “protein synthesis”

Nucleic Acids DNA, the Genetic CodeRNA the Trait Maker

Nucleotides: monomers of nucleic acids Pentose, a 5C sugar Nitrogen Base Phosphate