Chemistry of Life

Macromolecules

Macromolecules

• Smaller molecules linked together to create large molecules

– Polymerization

– Have specific 3d shape • Proteins - enzymes, hormones, structure,

transport

• Carbohydrates – storage, structure

Macromolecules

• Carbon’s properties enable it to make many different molecules

Isomers = molecules with the same formula but different structural

formulae

Specific 3d shape

Ethane

Ethanol

Functional group

Functional groups -Create the necessary variety of shapes of macromolecules for life to exist

Dehydration synthesis =

enzymatically controlled

formation of macromolecules by removal of

water

Macromolecules

• Macromolecules are broken down (catalyzed) by HYDROLYSIS (‘water splitting’)

• Requires specific enzyme(s)

Check Point

• What are macromolecules?

• Why is carbon so important to life?

• What are functional groups?

• How are macromolecules formed?

• How are macromolecules broken down?

• What molecule makes up most organisms?

Macromolecules Important to Life

• Carbohydrates

• Lipids

• Proteins

• Nucleic acids

Macromolecules

• What do you need to know for each macromolecule:

– Monomers

– Function in organisms

Carbohydrates:

• Carbon + water (hydrate)• Monomers = monosaccharide• Monosaccharides – sugars

– Glucose– Fructose– Galactose– Ribose– Deoxyribose

Monosaccharides

• Monomers may be functional:

– Glucose is primary source of energy for organisms

• Glucose - C6H12O6

• Many monomers form rings in solutions to become more stable

Carbohydrates

• Monosaccharide + monosaccharide =

• Disaccharide

• Glucose + glucose = maltose

• Glucose + fructose = sucrose

• Glucose + galactose = lactose

Polysaccharides

• Polymers of monosaccharides

• Type of monosaccharide and arrangement creates variability in polysaccharides– Starch (Amylose, amylopectin) = plants

– Glycogen = glucose storage for animals

– Cellulose = plant cell walls

– Chitin = exoskeleton of arthropods, some fungi

Carbohydrates: Function

• Energy; stored energy _____(?)

• Structure – ___________(?)

• Cell-to-cell communication, identification (glycoproteins, glycolipids) ______(?)

Lipids • InsolubleInsoluble in water; (long, nonpolar hydrocarbon

chains) • Three types:

– Fats, oils, waxes– Phospholipids – Steroids

Lipids: Fats

• Macromolecules of glycerol + 3 fatty acids

• Fatty acids = hydrocarbon chain (16-18 carbons)

• Fats = triglycerides (3 fatty acids)

• Structure of the fatty acid chains creates different kinds of fats

Fats• Fatty acids may have more or less carbons

atoms in their chains

• Carbon atoms may be double bonded

– Double bonds reduce the number of hydrogen atoms in the chain

– Causes chain to bend

Fats

• Fatty acid chains with double bonds have less hydrogen

• Chains with the maximum amount of hydrogen (no double bonds) are said to be ‘saturated’

• Chains with less than the maximum are said to be ‘unsaturated’

Types of Fats

• Saturated

• No double bonds

• Solids @ (200)

• Animal fats

• Bacon grease, lard, butter

• Unsaturated • Double bond(s)• Liquids @ (200)• Plant fats (oil)• Corn, peanut, olive

oils

Triglycerides

• Important to diet

• Limit amount of saturated fats

• Hydrocarbon chains are high in energy

• More difficult to breakdown

• Link to triglycerides and arteriosclerosis

Lipids: Phospholipids

• Glycerol + 2 fatty acids • 3rd position on the glycerol is

taken by a phosphate group• Major component of cell

membrane

Lipids: Steroids

• 4 fused carbon rings• Cholesterol

– Cell membranes – Help to moderate the effects of extreme

temperatures • Precursors of sex hormones – estrogen, testosterone• Too much causes atherosclerosis (?)

Cholesterol

Proteins

• Many shapes = many functions

• Polymers of AMINO ACIDS

• Linked by PEPTIDE BONDS

• POLYPEPTIDES

• Proteins = folded, shaped polypeptides

Proteins: Amino Acids

• 20 different amino acids• R group determines properties of the amino

acid • May be nonpolar, or polar; acidic or alkaline• Essential amino acids - body cannot produce

on its own, must be part of the diet

Tremendous Variety

Proteins

• Peptide bonds are produced by DEHYDRATION SYNTHESIS

• String of polypeptide bonds - POLYPEPTIDE

Proteins

• Function depends upon shape

• Globular

• Fibrous = ‘stringy’

• CONFORMATION = 3d shape caused by H-bonds

– Fold and twist the amino acids

Protein Structure

• Sequence of amino acids

– Determined by genetic code– ‘Goof’ in sequence can have harmful or

lethal effects

Denaturation • Alteration of conformational shape

• Caused by:

– Heat – body T

– pH -

– Salinity

– Organic solvents (alcohols, acetone, etc.)

– Inorganic chemicals that dissolve bonds (HCl)

Denaturation

• Some proteins change shape in order to function

– Receptor, contractile

Nucleic Acids

• DNA, RNA

• Polymers of nucleotides

• Nucleotide:

– Simple sugar (ribose or deoxyribose)

– Nitrogenous base

– Phosphate group (PO4)

4 nitrogenous bases;

Nucleic Acids

• Nitrogenous bases are complimentary

• A-T

• C-G

• Hydrogen bonds

• Sugar-phosphate backbone

H bonding

Relationship between

nucleic acids and proteins