The Chemistry of Life

Organic Molecules

• Organic Molecules– Contain carbon and hydrogen

• Four 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

EsterHydroxyl

CarboxylAmino

SulfhydrylPhosphate

Type of Molecule Chemical Structure FunctionsCarbohydrates

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

Complex Carbohydrates - Polysaccharides

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

Lipids

• Hydrophobic• Energy-rich• Used for:

protection, insulation, energy store

Types of Organic Molecules - Lipids

• Lipids – DO NOT dissolve in water• Fatty Acids

– Saturated – all single bonds and hydrogen bonds, hard to break down

– Unsaturated – has at least 1 double bond, liquid at room temperature

– used to make or catabolize other lipids• Triglycerides (Fats) – fatty acids + glycerol

– protection, insulation, energy storage• Sterols – lipids with carbon rings

– Vitamin D, cortisone, cholesterol, testosterone (hormones)• Waxes – fatty acids + alcohols or other hydrocarbons

Types of Organic Molecules - Lipids

• Phospholipids – Glycerol + 2 fatty acids + phosphate– Amphipathic – have polar and nonpolar ends

• Only polar end can bond to water molecules• Hydrophobic – Cannot bond with water• Hydrophilic – Will bond with water

– Build cell membranes• Eicosanoids – prostaglandins, leukotrienes• Carotenes – make Vitamin A, antioxidants• Vitamin E, K – healing, antioxidant, blood clotting• Lipoproteins – transport other lipids in blood

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

Nucleic Acids

DNA