Chapter 02 Lecture Outline: Matter, Atoms, Elements, and Chemical Bonds

Vocabulary flashcards covering key terms from the lecture notes.

Matter

Anything that has mass and occupies space.

Solid

A form of matter with a definite shape and volume (e.g., bone).

Liquid

A form of matter with definite volume that adapts to its container (e.g., blood).

Gas

A form of matter with no fixed shape or volume (e.g., oxygen).

Atom

The smallest particle that retains the chemical properties of an element.

Element

A substance made of only one type of atom; 92 natural elements make up matter.

Periodic table

Chart organizing elements by atomic number and properties.

Neutron

Neutral subatomic particle in the nucleus; mass ~1 amu.

Proton

Positively charged subatomic particle in the nucleus; mass ~1 amu.

Electron

Negatively charged subatomic particle; very small mass, in orbitals around the nucleus.

Orbital

Region around the nucleus where an electron is likely to be found.

Atomic number

Number of protons in an atom; determines identity; shown above the symbol.

Atomic mass

Total mass of protons and neutrons in the nucleus; used in isotope calculations.

Isotope

Atoms of the same element with the same number of protons but different neutrons.

Radioisotope

Unstable isotope that decay and emit radiation.

Half-life (physical)

Time required for half of a radioactive substance to decay.

Half-life (biological)

Time required for half of a substance to be eliminated from the body.

Ion

Atom with a positive (cation) or negative (anion) charge.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Octet rule

Atoms tend to have eight electrons in their outer shell for stability.

Valence shell

Outermost electron shell of an atom.

Ionic bond

Electrostatic attraction between oppositely charged ions.

Covalent bond

Particles share electrons between atoms.

Single covalent bond

One pair of electrons shared between atoms.

Double covalent bond

Two pairs of electrons shared between atoms.

Triple covalent bond

Three pairs of electrons shared between atoms.

Polar covalent bond

Electrons shared unequally, creating partial charges.

Nonpolar covalent bond

Electrons shared equally between atoms.

Electronegativity

Attraction of an atom for electrons in a bond; increases across a period.

Hydrogen bond

Weak bond between a partially positive H and a partially negative atom in polar molecules.

Isomer

Molecules with the same formula but different arrangement in space.

Structural formula

Shows number, type, and arrangement of atoms in a molecule.

Molecular formula

Indicates the number and type of atoms in a molecule.

Amphipathic

Molecule with both polar and nonpolar regions (e.g., phospholipids).

Intermolecular attractions

Weak forces between molecules (e.g., hydrogen bonds, van der Waals).

Hydration shell

Layer of water molecules surrounding a dissolved ion or molecule.

Hydrophilic

Water-loving; substances that dissolve in water.

Hydrophobic

Water-fearing; nonpolar substances poorly dissolve in water.

Surfactant

Liprotein that reduces surface tension to prevent alveolar collapse.

Water as universal solvent

Water dissolves many substances, especially polar molecules and ions.

Nonelectrolyte

Dissolves in water but does not dissociate into ions.

Electrolyte

Dissolves and dissociates into ions, conducting electricity.

pH

Measure of hydrogen ion concentration in solution; scale 0–14.

Acids

Substances that donate H+; lower pH.

Bases

Substances that accept H+; raise pH.

Buffer

Substance that resists pH changes by absorbing or releasing H+.

Neutralization

Acid or base is neutralized to pH ~7 by adding opposing reactant.

Solution

Homogeneous mixture; solute dissolved in solvent.

Suspension

Mixture with larger particles that settle out; appears cloudy.

Colloid

Mixture with intermediate-sized particles; remains mixed; scatters light.

Emulsion

Water and nonpolar liquid that do not mix unless shaken.

Molarity

Moles of solute per liter of solution; temperature can affect value.

Molality

Moles of solute per kilogram of solvent; independent of temperature.

Osmolarity

Number of particles in 1 liter of solution.

Osmolality

Number of particles in 1 kilogram of water.

Mole

Amount of substance containing 6.022×10^23 units; mass in grams equals molar mass.

Macromolecule

Large organic molecule; polymers like carbs, proteins, lipids, nucleic acids.

Polymer

Molecule made of repeating monomer units.

Monomer

Small repeating subunit that forms polymers.

Dehydration synthesis

Condensation reaction forming a covalent bond and releasing water.

Hydrolysis

Breaking bonds with the addition of water.

Carbohydrates

Organic molecules with C, H, O; formula (CH2O)n; includes sugars and starches.

Monosaccharide

Simple sugar (e.g., glucose).

Disaccharide

Two monosaccharides joined (e.g., sucrose, lactose, maltose).

Polysaccharide

Many monosaccharides linked together (e.g., glycogen, starch, cellulose).

Glucose

Six-carbon sugar; primary energy source for cells.

Glycogen

Stored glucose in liver and skeletal muscle.

Nucleic acids

DNA and RNA; store and transfer genetic information.

Nucleotide

Monomer of nucleic acids; sugar, phosphate, and nitrogenous base.

Pyrimidines

Cytosine, Uracil, Thymine (DNA/RNA bases).

Purines

Adenine and Guanine.

DNA

Double-stranded nucleic acid; stores genetic information; bases pair A-T, G-C.

RNA

Single-stranded nucleic acid; contains A, G, C, U; uses ribose sugar.

ATP

Adenosine triphosphate; energy currency of the cell.

NAD+

Nicotinamide adenine dinucleotide; electron carrier in energy production.

FAD

Flavin adenine dinucleotide; electron carrier.

Protein

Macromolecule of one or more polypeptides; performs diverse functions.

Amino acid

Monomer of proteins; contains amino group, carboxyl group, and R group.

Peptide bond

Bond linking amino acids via dehydration synthesis.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Alpha helix and beta sheet patterns in proteins.

Tertiary structure

Three-dimensional shape of a single polypeptide.

Quaternary structure

Arrangement of multiple polypeptide chains in a protein.

Denaturation

Loss of protein structure and function, usually irreversible.

Prosthetic group

Nonprotein component covalently bound to a protein.

Lipids

Diverse fats; triglycerides, phospholipids, steroids, eicosanoids.

Triglyceride

Glycerol + three fatty acids; long-term energy storage.

Phospholipid

Amphipathic lipid forming cell membranes; polar head, nonpolar tails.

Steroid

Hydrocarbon rings (cholesterol, hormones) with diverse roles.

Eicosanoid

Signaling molecules from arachidonic acid (prostaglandins, etc.).

Glycoprotein

Protein with carbohydrate attached; influences cell functions (e.g., ABO).

Phospholipid bilayer

Two-layer membrane with polar heads outward and nonpolar tails inward.

Chaperone

Protein that assists in proper folding of other proteins.

Alpha helix

Coiled secondary structure common in fibrous proteins.

Beta sheet

Sheet-like secondary structure common in many proteins.

Globular protein

Compact, roughly spherical protein structure.

Fibrous protein

Extended, filamentous protein structures.

Heme group

Iron-containing prosthetic group in hemoglobin.