Chapter 2: Basic Chemistry

Vocabulary flashcards covering key terms from the Basic Chemistry lecture. Each card defines a essential concept or term introduced in Chapter 2.

Matter

Anything that occupies space and has mass.

Chemistry

The science of the structure and interactions of matter.

Element

A substance that cannot be split into simpler substances by ordinary chemical means.

Atom

The smallest unit of matter that retains the properties of an element; composed of protons, neutrons, and electrons.

Proton

Positively charged subatomic particle located in the nucleus.

Neutron

Neutral subatomic particle located in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Nucleus

The center of an atom containing protons and neutrons.

Electron shell

Regions around the nucleus where electrons are found; shells have maximum capacities.

Valence shell

Outermost electron shell; its electrons determine bonding behavior.

Octet rule

Atoms tend to have eight electrons in their valence shell to be stable.

Atomic number

Number of protons in the nucleus; also equals the number of electrons in a neutral atom.

Mass number

Total number of protons and neutrons in an atom.

Isotope

Atoms of the same element with different numbers of neutrons.

Radioactive isotope

An isotope that is unstable and decays, emitting radiation.

Dalton (amu)

Unit of atomic mass; approximately the mass of a proton or neutron.

Ion

An atom with a positive or negative charge due to gain or loss of electrons.

Molecule

Two or more atoms bonded together.

Compound

A substance that can be broken down into two or more elements by chemical means.

Free radical

Atom or group with an unpaired electron; highly reactive.

Antioxidant

Substance that neutralizes free radicals by donating electrons.

Ionic bond

Bond formed by attraction between oppositely charged ions.

Cation

Positively charged ion that has lost electrons.

Anion

Negatively charged ion that has gained electrons.

Electrolyte

Ionic compound that dissociates into ions in solution.

Covalent bond

Bond formed by sharing one or more pairs of electrons.

Nonpolar covalent bond

Electrons are shared equally between atoms.

Polar covalent bond

Electrons are shared unequally; one atom attracts electrons more strongly.

Hydrogen bond

Weak bond between a hydrogen atom and another electronegative atom (often O or N) linking molecules.

Reactants

Starting substances in a chemical reaction.

Products

Substances formed at the end of a chemical reaction.

Law of conservation of mass

Mass of reactants equals mass of products in a chemical reaction.

Metabolism

All chemical reactions occurring in an organism.

Potential energy

Energy stored by matter due to its position.

Kinetic energy

Energy of matter in motion.

Chemical energy

Energy stored in chemical bonds.

Exergonic

Reactions that release energy because bonds broken have more energy than formed.

Endergonic

Reactions that require energy input to proceed.

Activation energy

Minimum energy required to start a reaction.

Catalyst

Substance that speeds up a reaction by lowering activation energy and is not consumed.

Synthesis

A reaction where two or more substances combine to form a larger molecule.

Decomposition

A reaction where a molecule is broken down into smaller parts.

Exchange

A reaction involving the replacement of atoms by other atoms.

Reversible

A reaction in which products can revert to reactants.

Oxidation

Loss of electrons.

Reduction

Gain of electrons.

Inorganic compound

Compounds that usually lack carbon-hydrogen bonds.

Organic compound

Compounds that contain carbon and hydrogen, often with oxygen, and typically have covalent bonds.

Water

The most important inorganic compound; polar solvent essential for reactions.

Polarity

Uneven sharing of electrons causing partial charges within a molecule.

Hydrophilic

Substances that dissolve in water.

Hydrophobic

Substances that do not dissolve in water.

Solvent

The dissolving medium in a solution.

Hydrolysis

Breaking large molecules apart by adding water.

Dehydration synthesis

Joining of two simple molecules with removal of a water molecule.

pH

A measure of how acidic or basic a solution is.

Buffer

System that resists pH changes, usually comprising a weak acid and weak base.

Carbonic acid–bicarbonate buffer

Major body buffer system: CO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3-.

Monosaccharide

Simple sugar; 3–7 carbon atoms.

Glucose

Main energy source; a hexose sugar.

Disaccharide

Two monosaccharides joined by dehydration synthesis (e.g., sucrose).

Sucrose

Disaccharide formed from glucose and fructose.

Polysaccharide

Large carbohydrate made of many monosaccharides (e.g., glycogen, starch, cellulose).

Glycogen

Storage form of glucose in liver and skeletal muscle.

Cellulose

Plant polysaccharide indigestible by humans.

Lipid

Macromolecule composed of carbon, hydrogen, and oxygen; hydrophobic; fats and oils.

Fatty acid

Component of lipids; may be saturated or unsaturated.

Saturated

Fatty acids with only single bonds.

Unsaturated

Fatty acids with one or more double bonds.

Triglyceride

Most common lipid; glycerol with three fatty acids; energy storage.

Essential fatty acids (EFAs)

Fatty acids that must be obtained from diet (e.g., omega-3, omega-6).

Omega-3

Polyunsaturated fatty acid with health benefits; must be obtained from diet.

Omega-6

Polyunsaturated fatty acid; important but often abundant in the diet.

Phospholipid

Amphipathic lipid; major component of cell membranes.

Amphipathic

Molecule having both polar and nonpolar regions.

Steroid

Lipids with four fused carbon rings; includes cholesterol and hormones.

Cholesterol

Steroid important in membranes and as a precursor for other steroids.

Eicosanoid

Lipid mediators including prostaglandins and leukotrienes.

Prostaglandin

Eicosanoid involved in inflammation and other physiological responses.

Leukotriene

Eicosanoid involved in inflammatory and allergic responses.

Protein

Macromolecule that provides structure, regulates processes, and acts as enzymes and transporters.

Amino acid

Monomer of proteins; contains an amino group, a carboxyl group, a central carbon, hydrogen, and an R group.

Peptide bond

Covalent bond linking amino acids in a chain.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Local folding (alpha helices, beta sheets) stabilized by hydrogen bonds.

Tertiary structure

Three-dimensional folding of a protein.

Quaternary structure

Protein comprised of two or more polypeptide chains.

Denaturation

Loss of protein structure and function due to heat, pH, or chemicals.

Fibrous protein

Insoluble proteins with long strands (e.g., collagen, elastin, keratin, fibrin).

Globular protein

Soluble, globe-shaped proteins (e.g., enzymes, antibodies, hemoglobin).

Enzyme

Protein catalyst; typically ends with -ase and is highly specific and regulated.

Nucleic acid

Macromolecule containing carbon, hydrogen, oxygen, nitrogen, and phosphorus.

DNA

Deoxyribonucleic acid; stores genetic information.

RNA

Ribonucleic acid; guides protein synthesis from genetic information.

Nucleotide

Monomer of nucleic acids; composed of a base, a sugar, and a phosphate.

DNA fingerprinting

Technique to identify individuals based on unique DNA patterns.

ATP

Adenosine triphosphate; primary energy-storing molecule in cells.

ADP

Adenosine diphosphate; produced when ATP releases energy.

Cellular respiration

Process of breaking down glucose to produce ATP; includes glycolysis, and aerobic/anaerobic pathways.

Glycolysis

First stage of cellular respiration; glucose to pyruvic acid; yields 2 ATP.