Carbohydrates (sugars)

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

Maltose glu + glu

Lactose glu + galac

Sucrose glu + 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 molec.

• 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 Code RNA the Trait Maker

Nucleotides: monomers of nucleic acids

• Pentose, a 5C sugar

• Nitrogen Base

• Phosphate