Chapter 2: Chemistry of Life

Vocabulary flashcards covering atomic structure, chemical bonding, water properties, pH, macromolecules, and ATP based on Chapter 2 lecture notes.

Proton

A positively charged subatomic particle located in the nucleus of an atom.

Neutron

A subatomic particle with no charge located in the nucleus of an atom.

Electron

A negatively charged subatomic particle found in the electron cloud or orbitals of an atom.

Atomic Number

The total number of protons in an atom.

Mass Number

The sum of protons and neutrons in an atom.

Valence Electrons

Electrons in the outer shell that determine reactivity; atoms interact to achieve stable valence shells.

Ionic Bonds

Bonds formed by the transfer of electrons, creating ions where opposite charges attract (example: $\text{NaCl}$).

Covalent Bonds

Bonds formed by the sharing of electrons, which can be polar or nonpolar (examples: $\text{H}_2\text{O}$, $\text{CO}_2$).

Cohesion

The property of water where water molecules stick to other water molecules.

Adhesion

The property of water where water molecules stick to other hydrophilic surfaces.

Acids

Substances that donate $\text{H}^+$ ions and have a pH less than $7$ (example: $\text{HCl}$).

Bases

Substances that accept $\text{H}^+$ or release $\text{OH}^-$, having a pH greater than $7$ (example: $\text{NaOH}$).

pH Scale

A scale ranging from $0$ to $14$ measuring acidity or basicity, where each pH unit represents a $10\times$ change in $\text{H}^+$ concentration.

Dehydration Synthesis

A chemical reaction that removes water to build polymers by joining monomers together.

Hydrolysis

A chemical reaction that adds water to break polymers apart; important in digestion.

Monosaccharides

Single sugars that act as the subunit monomers of carbohydrates (example: glucose).

Disaccharides

Carbohydrates composed of two sugars (example: sucrose).

Polysaccharides

Carbohydrates composed of many sugars (examples: glycogen, starch, cellulose).

Neutral Fat

A lipid structure composed of glycerol and $3$ fatty acids (hydrophobic) that functions in long-term energy storage.

Phospholipid

A lipid composed of a hydrophilic phosphate head and $2$ hydrophobic fatty acids, forming cell membranes.

Steroids

Hydrophobic lipids characterized by a $4$ carbon ring structure (example: hormones).

Proteins

Macromolecules composed of amino acids folded into compact 3D shapes that determine function; roles include enzymatic, structural (collagen), transport (hemoglobin), movement (actin and myosin), signaling, and defense (antibodies).

DNA

A double-helix nucleic acid containing deoxyribose sugar and bases A, T, C, G that stores genetic information.

RNA

A usually single-stranded nucleic acid containing ribose sugar and bases A, U, C, G that helps produce proteins.

ATP

Adenosine triphosphate, the cell's main energy currency that powers cellular work and releases energy via $\text{ATP} \rightarrow \text{ADP} + \text{P}_i$.