Bio U1: Carbon and the Molecular Diversity of Life

Carbon

Backbone of life; can form 4 stable covalent bonds, allowing diverse molecules.

Organic Chemistry

Study of carbon compounds.

Hydrocarbons

Molecules made of only carbon and hydrogen; nonpolar, hydrophobic, stable.

Isomers

Molecules with the same molecular formula but different structures and properties.

Structural Isomers

Isomers that differ in the arrangement of atoms.

Stereoisomers

Isomers that differ in spatial arrangement; can have different biological effects.

Thalidomide Example

Stereoisomer caused severe birth defects despite similar formula.

Functional Groups

Specific chemical groups attached to carbon skeletons that determine molecular properties and reactions.

Hydroxyl (–OH)

Found in alcohols; polar; increases solubility in water; names often end in –ol (e.g., ethanol).

Carbonyl (C=O)

Found in aldehydes (end of chain) and ketones (middle of chain); polar.

Carboxyl (–COOH)

Acidic; found in amino acids and fatty acids; donates H+.

Amino (–NH2)

Basic; found in amino acids; can pick up H+.

Sulfhydryl (–SH)

Forms thiols; stabilizes protein structures via disulfide bonds.

Phosphate (–PO4)

Highly negative; transfers energy (e.g., ATP, GTP).

Methyl (–CH3)

Nonpolar; can affect gene expression and make molecules more hydrophobic.

Hormone Differences

Male and female hormones share a carbon skeleton but differ in functional groups, leading to different biological effects.

Polymer

Large molecule made by linking monomers in a chain via covalent bonds.

Monomer

Small building block that joins to form polymers.

Dehydration Synthesis

Reaction that joins monomers by removing water; requires energy and enzymes.

Hydrolysis

Reaction that breaks polymers into monomers by adding water; releases energy.

Macromolecules

Large biological molecules: carbohydrates, lipids, proteins, nucleic acids.

ATP

Adenosine triphosphate; main energy transfer molecule containing phosphate groups.