Organic Molecules Biochemistry

Organic Molecule Is a hydrocarbon Carbon bonds to hydrogen Simplest hydrocarbon is when 4 hydrogen atoms bond to one carbon (methane) CH 4

A Little Less Simple Carbon binds to other carbon atoms This is the uniqueness of carbon: it can bind to itself Ethane is C 2 H 6

A Little More Less Simple Carbon likes to form long chains Pentane: 5 carbons C 5 H 12

A Little More Complicated Branched chains Isohexane C 6 H 14

A Lot More Complicated Form rings C 6 H 12 Cyclohexane

Even More Complicated Carbon-Carbon single bonds Carbon-Carbon double bonds Carbon-Carbon triple bonds As you increase the number of bonds between carbons, the number of hydrogen atoms decreases

How many single vs double bonds? Determines saturated or unsaturated Have special names Saturated has only single bonds—every carbon is bonded singly to another carbon and hydrogen occupies every other spot These are Alkanes

Alkenes Unsaturated Contain one or more double bonds between carbon atoms Not EVERY possible spot is occupied by a hydrogen

Alkynes Contain a triple bond Fewer hydrogen atoms Ethyne

Living Things Simple hydrocarbons not common in living organisms They form the building blocks of more complex organic molecules that make up living organisms

Four Categories Based on function Carbohydrates Lipids Proteins Nucleic Acids

All four have in common… Carbon backbone Other atoms, usually H,O,N,P,and/or S These atoms form functional groups, which we can recognize These groups replace the H that would be in a typical hydrocarbon

In common… all form by dehydration synthesis This means single units (monomers) join together; water is removed to join them No polymers in lipids Enzyme catalyzed

Dehydration Synthesis

Functional groups give characteristics Attaching the functional groups to the carbon backbone gives the chemical characteristics of the organic molecule Methane gas vs. methanol liquid Methanol

Functional groups Formaldehyde has a strong odor, highly reactive Formic Acid, only slightly different— why an acid?

Hydrocarbons Only have H attached to carbon backbone Do not break easily Very stable

Carbohydrates Sugars and Starches #1 Energy Source (quick)

Characteristic of Carbohydrates A 2 to 1 ratios of Hydrogen to Oxygen C 6 H 12 O 6 The basic monomer (or building block) is the monosaccharide

Building Chains Two monosaccharides is a disaccharide Many is a polysaccharide A few is an oligosaccharide The simple chains are sugars The longer chains are starches

Starches

Sugars Consists of three or more C atoms with either an aldehyde or a ketone group And at least 2 OH groups Formed by dehydration synthesis

Simple Sugars Like to form ring formations Glucose, galactose, fructose all have the same molecular formula Different arrangements

Starch: the main polysaccharide Other polysaccharides include glycogen (storage in animals) Cellulose (plant material Pectin (plant material) Starch (storage in plants)

Lipids

Characteristics Do not dissolve in water Hydrophobic Greasy or oily Energy Storage Structural components (esp membranes) Cannot polymerize

Energy Efficient Number one method of energy storage Long term Can store twice as much energy as carbohydrates Due to high number of C-H bonds—very energy efficient

Common Types Triglycerides: one glycerol and three fatty acids (70 types) Fat is solid at room temperature (saturated) Oils are liquid (unsaturated)

Saturated vs Unsaturated Saturated: contains a H at every possible location on the fatty acids Unsaturated: contains one or more double bonds Saturated

Phospholipids Split personality A glycerol and two fatty acids A phosphate group takes the place of the third fatty acid Glycerol is hydrophobic Phosphate is hydrophyllic

Phospholipids

Sterols (Steroids) No fatty acid tails All have backbone of 4 fused carbon rings with functional groups Hormones and cholesterol are in this group Testosterone

Waxes Fatty acids linked to a long chain with alcohol Hydrophobic Waterproof covering for insects, leaves, skin on fruit

Proteins

Most diverse group Many functions Shape determines function Functions include: structural, hormones, enzymes Monomer is the amino acid

Each amino acid has One carbon with 4 groups attached The 4 groups are: amine group NH 2 Carboxyl group COOH Hydrogen R group—varies with each amino acid

Amino Acids The R group is what gives each amino acid its physical and chemical properties It does this by shape and the fact that the R group can be polar or nonpolar; acidic or basic

Making protein chains The more amino acids in the chain, the more complex the protein The amine group from one joins to the carboxyl end of the other This is known as a peptide bond

Protein Structure Proteins have a 3D shape Four factors contribute to the shape: primary structure, secondary structure, tertiary structure, and quaternary structure

Primary Structure This is the amino acid sequence. There are 20 different amino acids Which ones, and in what order, determines the primary structure

Secondary Structure Strand folds or coils Caused by hydrogen bonds between non adjacent amino acids

Tertiary Structure Actual 3D shape Bends and loops into a glob as R groups react with other R groups

Quaternary Structure Two or more polypeptide chains have joined together by numerous weak hydrogen bonds and/or covalent bonds between R groups