Lecture 2a: Organic Chemistry

Vocabulary flashcards summarizing essential terms and definitions from Lecture 2a on the chemical foundations of life.

Life (general characteristics)

Earth organisms share biological molecules, maintain homeostasis, evolve, and require liquid water

Matter

Anything that has mass and takes up space

States of Matter

Solid, liquid, and gas

Conservation of Matter

Principle that matter is neither created nor destroyed, only transformed

Element

A substance that cannot be broken down by ordinary chemical reactions; 118 are known

Atom

Smallest particle displaying the properties of an element

Proton

Positively charged particle located in an atom’s nucleus

Neutron

Neutral particle located in an atom’s nucleus

Electron

Negatively charged particle moving in orbitals around the nucleus

Valence Shell

The outermost electron shell of an atom

Potential Energy (in electrons)

Energy electrons possess because of their position in electron shells

Electron Shell

Energy level around an atom where electrons are found

Atomic Number

Number of protons in an atom; defines the element

Isotope

Form of an element with the same number of protons but different numbers of neutrons

Mass Number

Total number of protons plus neutrons in the most common isotope of an element

Molecule

Two or more atoms chemically bonded together

Compound

Substance composed of two or more different kinds of atoms

Chemical Bond

Force of attraction holding atoms together in molecules

Ionic Bond

Chemical bond formed between oppositely charged ions

Covalent Bond

Chemical bond where atoms share electron pairs

Hydrogen Bond

Weak attraction between a hydrogen atom in one molecule and an electronegative atom in another

Oxidation

Loss of one or more electrons by an atom

Reduction

Gain of one or more electrons by an atom

Activation Energy

Energy needed to start a chemical reaction

Polar Molecule

Molecule with unequal charge distribution; e.g., water

Solvent

Substance (often liquid) that dissolves a solute

Solute

Substance that is dissolved in a solvent

Solution

Homogeneous mixture of solute in solvent

Hydrophilic

Water-loving; readily dissolves in water

Hydrophobic

Water-hating; does not dissolve in water

Cohesion

Attraction between like molecules; causes high surface tension in water

Adhesion

Attraction between unlike molecules

Specific Heat

Amount of energy required to raise 1 g of a substance 1 °C; high in water

Heat of Vaporization

Energy needed for 1 g of liquid to become vapor; high in water

Ion

Atom or molecule with a net positive or negative charge

Anion

Negatively charged ion

Cation

Positively charged ion

Acid

Substance that releases hydrogen ions (H⁺) in solution

Base

Substance that accepts or bonds with hydrogen ions

pH Scale

Logarithmic scale (0-14) measuring acidity/basicity; 7 is neutral

Buffer

Substance that resists changes in pH by donating or accepting H⁺

Organic Chemistry

Branch of chemistry focused on carbon-containing compounds

Carbon (chemical versatility)

Element that forms four covalent bonds, enabling complex molecules

Macromolecule

Large organic molecule composed of smaller subunits

Biomolecule

Organic molecule (carbohydrate, lipid, protein, nucleic acid) essential to life

Carbohydrate

Energy-providing molecule made of carbon, hydrogen, and oxygen

Protein

Polymer of amino acids linked by peptide bonds

Amino Acid

Monomer containing an amino group, carboxyl group, and side chain

Peptide Bond

Covalent bond joining amino acids in proteins

Lipid

Hydrophobic molecule mainly of carbon and hydrogen; includes fats, oils, and steroids

Nucleic Acid

Polymer of nucleotides; DNA or RNA

Nucleotide

Monomer of nucleic acids composed of a sugar, phosphate, and nitrogenous base

DNA (Deoxyribonucleic Acid)

Double-stranded nucleic acid that stores hereditary information

RNA (Ribonucleic Acid)

Single-stranded nucleic acid involved in protein synthesis