The Chemistry of Life

Organic Molecules Generate Life’s Form and Function

• Organic molecules– Contain carbon and hydrogen

• 4 most abundant types– Carbohydrates, lipids, proteins, and nucleic

acids• Monomers link together to form polymers

– Link by dehydration synthesis– Broken apart by hydrolysis

Functional Groups of Organic Molecules

Group Example

Hydroxyl

Methanol

Carbonyl

Butanone

Carboxyl

Acetic acid

Functional Groups of Organic Molecules

Group Example

Amino

Methylamine

Phosphate

Glyceraldehyde 3-phosphate

Type of Molecule Chemical Structure Functions

Carbohydrates

Simple Sugars MonosaccharidesDisaccharides

quick fuel for metabolism, being used both as an energy source (glucose being the most important in nature) and in biosynthesis

Complex Carbohydrates (starch, cellulose, chitin)

Polysaccharides cellulose and chitin are structural polysaccharides; others are used for energy

Lipids

Triglycerides (fats, oils) glycerol and three fatty acids

enable the bidirectional transference of adipose fat and blood glucose from the liver

Phospholipids glycerol, a diglyceride, a phosphate group, and a simple organic molecule

major component of all cell membranes as they can form lipid bilayers

Sterols fused four-ring core structure

important component of membrane lipids; hormones

Waxes long chain fatty acids and primary alcohols

provide waterproofing (are insoluble in water)

Proteins one or more long chains of amino acid residues

assist in cell function

Nucleic Acids (DNA, RNA)

polynucleotides—strands composed of nucleotides

store and use genetic information

Macromolecules of Life

Carbohydrates

• Monosaccharides – simple sugars– 5, 6 carbon atoms– Glucose, fructose

Carbohydrates

• Disaccharides – 2 monosaccharides joined by dehydration synthesis– Lactose, maltose (sugar cane, sugar beets)

Fructose Sucrose

Oligosaccharides

• Intermediate length carbohydrates– 3 – 100 monomers together– Glycoproteins – used for immunity

• Blood types – protein on the surface of blood cell for A, B, AB, O

Oligosaccharides

• Intermediate length carbohydrates– 3 – 100 monomers together– Glycoproteins – used for immunity

• Blood types – protein on the surface of blood cell for A, B, AB, O

Complex Carbohydrates - Polysaccharides

• Complex carbohydrates – Polysaharides– Cellulose, chitin, starch, glycogen

Lipids

• Lipids are hydrophobic and Energy-Rich– Do not dissolve in water– Not polymers – extremely diverse– Triglycerides

• 3 fatty acids plus glycerol– Saturated versus unsaturated

Function of Fats

• Fats protect , insulate and store energy• When energy resources low, body will pull from fat

stores (i.e. fat pad behind the eye)

Lipids

• Lipids are hydrophobic and Energy-Rich– Sterols

• 4 interconnected carbon rings• Vitamin D, cortisone, cholesterol, testosterone,

estrogen

Cholesterol Testosterone

Lipids

• Lipids are hydrophobic and Energy-Rich– Waxes

• Fatty acids combined with alcohols

• Stiff, water-repellant material

Honey encased in beeswax

Phospholipids• Amphipathic molecules

– Polar head– Nonpolar tails

Proteins

• Proteins – Carbohydrates with N atom– Need them to carry out most chemical reactions in

the body– Made of amino acids

• C atom + COOH, NH2, R-group (distinguishing character)• 20 types• Combined into proteins by peptide bonds

– Polypeptide = chain of amino acids– Protein = polypeptide shaped into protein shape– Denaturation – Modifying the structure of a protein

changing/destroying its function• pH, heat, salt

Proteins

Proteins

• Proteins Are Complex and Highly Versatile– Protein folding

• Primary (1º) structure• Secondary (2º) structure• Tertiary (3º) structure• Quaternary (4º) structure

– Genetic code specifies amino acid sequence

Proteins

• Denaturation: loss of function– Function depends on overall shape– Vulnerable to conditions that alter shape

• Heat, salt, pH

Nucleic Acids

• Nucleic Acids Store and Transmit Genetic Information– Nucleic acid (polymer)

• DNA – stores genetic information• RNA – enables cells to use DNA

– Nucleotide (monomer)• Nitrogenous base – A, G, T, C, or U

DNA