Chapter 2: Chemistry of Life Vocabulary

Comprehensive vocabulary flashcards covering basic chemistry concepts, atomic particles, chemical bonding, aqueous solutions, reactions, pH, macromolecules, and cellular energy from Chapter 2.

Proton

Positively charged subatomic particle located in the nucleus of an atom.

Neutron

Subatomic particle with no electrical charge located in the nucleus of an atom.

Electron

Negatively charged subatomic particle occupying energy levels around the nucleus.

Atomic number

The number of protons in an atom, which uniquely identifies the element.

Atomic mass

The combined sum of protons and neutrons, representing the approximate mass of an atom.

Element

A pure substance made of only one kind of atom, such as oxygen, carbon, or sodium.

Molecule

A structure composed of two or more atoms bound together, such as $O_2$ or $H_2O$.

Compound

A molecule containing more than one kind of atom, such as $H_2O$ or $NaCl$.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic bond

A chemical bond formed by the transfer of electrons and subsequent attraction between oppositely charged ions.

Electrolyte

A substance that dissociates in water into charged ions capable of carrying electrical currents in body fluids.

Covalent bond

A strong chemical bond formed when atoms share electrons.

Hydrogen bond

A weak attraction between nearby molecules or parts of molecules that helps stabilize shapes of water, DNA, and proteins.

Organic compound

A complex compound containing carbon-carbon and/or carbon-hydrogen covalent bonds, such as carbohydrates, lipids, proteins, and nucleic acids.

Inorganic compound

A compound that lacks characteristic carbon-carbon or carbon-hydrogen bonds, such as water, salts, and many acids/bases.

Solvent

The liquid medium in which solutes dissolve.

Aqueous solution

A fluid mixture in which water serves as the solvent.

Dehydration synthesis

A chemical reaction in which water is removed as smaller molecules join together to build a larger molecule.

Hydrolysis

A chemical reaction in which water is added to break a large molecule into smaller parts.

Acid

A chemical substance that shifts the balance toward higher $H^+$ concentration, resulting in a lower pH below 7.

Base

A chemical substance that shifts the balance away from $H^+$, resulting in a higher pH above 7.

pH

A scale expressing the relative $H^+$ concentration in a water-based solution.

Buffer

A chemical compound that absorbs excess acid or base to maintain relative pH stability.

Monosaccharide

A simple carbohydrate consisting of one sugar unit, such as glucose.

Disaccharide

A carbohydrate composed of two monosaccharide units, such as sucrose or lactose.

Polysaccharide

A complex carbohydrate composed of many sugar units, such as glycogen.

Glycogen

The main storage polysaccharide form of carbohydrate in the human body.

Triglycerides

Lipids formed from 1 glycerol molecule and 3 fatty acid chains that store energy for later use.

Phospholipid

A lipid containing a phosphorus-containing hydrophilic head and hydrophobic fatty-acid tails that form cell membranes.

Cholesterol

A lipid with a steroid ring structure that stabilizes cell membranes and serves as a precursor for steroid hormones.

Amino acids

The essential structural building blocks of proteins, connected together by peptide bonds.

Structural proteins

Proteins such as collagen and keratin that provide physical support to tissues or form tough waterproof fibers.

Functional proteins

Proteins such as enzymes, receptors, channels, and hormones that perform chemical, transport, or regulatory tasks.

Enzymes

Functional proteins that act as biological catalysts to speed up chemical reactions without being consumed.

Nucleotides

The monomer units of nucleic acids, each composed of a phosphate group, a sugar, and a nitrogenous base.

DNA

Deoxyribonucleic acid; a double-stranded nucleic acid containing deoxyribose sugar and bases A, T, C, G that stores master genetic instructions.

RNA

Ribonucleic acid; a single-stranded nucleic acid containing ribose sugar and bases A, U, C, G that acts as a temporary working copy for protein synthesis.

ATP

Adenosine triphosphate; a nucleotide-like molecule with high-energy phosphate bonds that provides usable cellular energy.

Atom (simple model)

Structural representation of an atom showing a central nucleus made of protons and neutrons, encircled by electrons in energy levels.

Chemical Bonds (3 types)

Overview diagram comparing ionic bonds (electron transfer), covalent bonds (electron sharing), and hydrogen bonds (weak attraction).

Phospholipid Bilayer

Structural arrangement of cell membranes featuring hydrophilic heads facing watery fluid and hydrophobic fatty-acid tails repelling water.

DNA vs RNA

Comparative summary illustrating structural and functional differences between DNA (master code with thymine) and RNA (working copy with uracil).