The Chemistry of Life - Video Notes (Vocabulary Flashcards)

Vocabulary flashcards covering key terms and concepts from the lecture notes on the chemistry of life.

Atom

The basic unit of matter; the smallest unit of an element that retains its properties.

Nucleus

The center of an atom that contains protons and neutrons.

Proton

Positively charged subatomic particle located in the nucleus.

Neutron

Electrically neutral subatomic particle located in the nucleus.

Electron

Negatively charged subatomic particle in constant motion around the nucleus; mass about 1/1840 that of a proton.

Isotope

Atoms of the same element with different numbers of neutrons.

Mass number

Total number of protons and neutrons in an atom’s nucleus.

Ion

An atom that has gained or lost electrons, giving it a net charge.

Element

A pure substance made of only one type of atom; cannot be broken down by chemical means.

CHON

The four most abundant elements in living organisms: carbon, hydrogen, oxygen, and nitrogen.

Compound

A substance formed by the chemical combination of two or more elements in definite proportions.

Water (H₂O)

A compound formed by two hydrogen atoms and one oxygen atom; example of a compound and universal solvent.

Ionic bond

Bond formed when electrons are transferred from one atom to another, creating oppositely charged ions that attract.

Covalent bond

Bond formed when electrons are shared between atoms.

Polar molecule

A molecule with unequal sharing of electrons, creating partial charges (poles).

Hydrogen bond

Weak attraction between a hydrogen atom on one molecule and an electronegative atom on another; up to 4 can form per water molecule.

Cohesion

Attraction of water molecules to each other.

Adhesion

Attraction of water molecules to other substances.

Solution

A homogeneous mixture where a solute is dissolved in a solvent.

Solvent

The substance doing the dissolving in a solution.

Solute

The substance dissolved in a solution.

Suspension

A mixture in which the particles are dispersed but not dissolved; can settle out.

pH

A measure of H⁺ ion concentration in a solution; 0–14 scale with 7 neutral.

Acid

A substance that releases H⁺ ions in solution.

Base

A substance that releases OH⁻ ions in solution.

Buffer

A weak acid or base that resists changes in pH.

Organic

Compounds that contain carbon bonded to hydrogen (C–H bonds).

Inorganic

Compounds that do not contain C–H bonds.

Carbon backbone

The carbon-based framework that forms the structure of organic molecules; carbon can form four covalent bonds.

Valence electrons

Electrons in the outermost shell; carbon has four valence electrons and can form four bonds.

Functional groups

Specific groups of atoms attached to carbon frameworks that determine properties and reactions.

Macromolecule

A giant molecule formed by polymerization of monomers (carbohydrates, lipids, proteins, nucleic acids).

Monomer

Small, repeating unit that builds polymers.

Polymer

Large molecule made of many monomers bonded together.

Dehydration synthesis

A condensation reaction that forms a bond while releasing a water molecule.

Hydrolysis

A reaction that breaks bonds by adding water.

Carbohydrates

Organic molecules made of C, H, O in a 1:2:1 ratio; quick energy source and structural roles.

Monosaccharides

Simple sugars such as glucose, fructose, and galactose.

Polysaccharides

Long chains of sugars such as starch, glycogen, and cellulose.

Lipids

Hydrophobic fats, oils, and waxes; mainly C and H with little O.

Triglycerides

Lipids formed from glycerol and three fatty acids; a major energy-storage molecule.

Phospholipids

Lipids with a phosphate group; major component of cell membranes.

Steroids

A class of lipids with four fused rings.

Saturated fats

Fats with no double bonds; typically solid at room temperature.

Unsaturated fats

Fats with one or more double bonds; typically liquids at room temperature.

Proteins

Macromolecules composed of amino acids; perform catalysis, structure, transport, signaling, and defense.

Amino acids

The 20 different monomers that make up proteins.

Peptide bonds

Covalent bonds linking amino acids in a protein.

Enzymes

Biological catalysts (usually proteins) that speed up chemical reactions by lowering activation energy.

Substrate

The reactant that binds to an enzyme.

Active site

The region of the enzyme where the substrate binds (lock-and-key model).

Nucleic acids

Store and transmit genetic information; include DNA and RNA.

DNA

Nucleic acid stored in the nucleus that carries hereditary information and guides cell activity.

RNA

Nucleic acid that carries instructions from DNA to ribosomes for protein synthesis.

Nucleotides

Monomers of nucleic acids consisting of a sugar, phosphate, and nitrogen base.

Activation energy

The minimum energy required to start a chemical reaction; enzymes lower this value.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed; enzymes are biological catalysts.