Just Enough Chemistry Vocabulary

Atoms, Ions, Molecules and More

A-B

• Acid – A substance that releases hydrogen ionsCharged atoms or molecules. (H⁺) in solutionA homogeneous mixture of two or more substances..
• Acidic – A solution with a pHA measure of hydrogen ion concentration in a solution. below 7, having a higher concentration of H⁺ ions.
• Adhesion – The tendency of waterThe universal solvent essential for life. moleculesGroups of atoms bonded together. to stick to other substances.
• ADPA molecule produced when ATP releases energy. (Adenosine diphosphate) – A molecule that can be converted to ATPThe energy currency of cells used for muscle contraction. by adding a phosphate group.
• Anabolism – The metabolic process that builds complex molecules from simpler ones, requiring energyThe capacity to do work or cause change..
• Anion – A negatively charged ion.
• Atoms – The smallest units of matter that retain the properties of an element.
• ATP (Adenosine triphosphate) – The primary energy carrier in cellsThe basic structural and functional units of life..
• Base – A substance that accepts hydrogen ions (H⁺) or releases hydroxide ions (OH⁻).
• Basic – A solution with a pH above 7, having a lower concentration of H⁺ ions.
• Buffers – Substances that resist changes in pH by absorbing or releasing H⁺ ions.

C

• cAMP(Cyclic AMP): Second messenger in many hormone signaling pathways. (Cyclic adenosine monophosphate) – A second messenger important in signal transduction.
• Catabolism – The metabolic process that breaks down molecules to release energy.
• Catalysts – Substances that speed up chemical reactions without being consumed.
• Cation – A positively charged ion.
• Cell adhesionThe tendency of water molecules to stick to other substances. – The ability of cells to stick together using membrane proteinsLarge molecules made of amino acids with various functions in the body..
• Cellular respirationThe process of gas exchange, including ventilation, external and internal respiration. – The process of breaking down glucoseA simple sugar that is the main source of energy for cells. to produce ATP.
• Chemical bonds – The forces holding atomsThe smallest units of matter that retain the properties of an element. together in molecules.
• Chemical reactivity – The ability of a substance to participate in chemical reactions.
• Cohesion – The attraction between molecules of the same substance, such as water molecules sticking together.
• Colloid – A mixture where small particles are dispersed but not dissolved in a liquid.
• Conformation – The specific three-dimensional shape of a molecule, especially proteins.
• Covalent bonds – Strong chemical bondsThe forces holding atoms together in molecules. formed by the sharing of electronsNegatively charged subatomic particles found in atoms. between atoms.

D-E

• Decomposition reactions – Chemical reactions that break down compounds into simpler substances.
• Dehydration synthesis – A reaction in which water is removed to join molecules together.
• Electrolytes – Substances that dissolve in water to form ions, conducting electricity.
• Electrons – Negatively charged subatomic particles found in atoms.
• Element – A pure substance composed of only one type of atom.
• Energy – The capacity to do work or cause change.
• Exchange reactions – Chemical reactions where parts of molecules are exchanged.

H-I

• Heat capacity – The amount of heat needed to raise the temperature of a substance.
• Hydration spheres – Water molecules that surround and dissolve ions.
• Hydrogen bonds – Weak attractions between hydrogen and electronegative atoms like oxygen or nitrogen.
• Hydrolysis – A reaction where water is used to break chemical bonds.
• Hydrophilic – Water-attracting molecules.
• Hydrophobic – Water-repelling molecules.
• Ionic bonds – Bonds formed by the transfer of electrons between atoms.
• Ions – Charged atoms or molecules.
• Isotopes – Atoms of the same element with different numbers of neutronsElectrically neutral particles in an atom’s nucleus..

K-N

• Kinetic energy – Energy of motion.
• Minerals – Inorganic elements essential for body function.
• Molecules – Groups of atoms bonded together.
• Monomers – Small molecules that link together to form polymersLarge molecules made of repeating monomer units..
• Neutral – A solution with a pH of 7.
• Neutrons – Electrically neutralA solution with a pH of 7. particles in an atom’s nucleusThe control center of the cell that contains DNA and directs cellular activities..

O-P

• Oxidation – The loss of electrons from a molecule.
• pH – A measure of hydrogen ion concentration in a solution.
• Polymers – Large molecules made of repeating monomer units.
• Potential energy – Stored energy, such as the energy held in chemical bonds.
• Products – The substances formed at the end of a chemical reaction.
• Proton acceptor – A baseA substance that accepts hydrogen ions (H⁺) or releases hydroxide ions (OH⁻).; a substance that binds hydrogen ions (H⁺) in solution.
• Proton donor – An acidA substance that releases hydrogen ions (H⁺) in solution.; a substance that releases hydrogen ions (H⁺) in solution.
• Protons – Positively charged subatomic particles in an atom’s nucleus.

R-S

• Reactants – The starting substances that enter into a chemical reaction.
• Reduction – The gain of electrons by a molecule.
• Solute – The substance that is dissolved in a solution.
• Solution – A homogeneous mixture of two or more substances.
• Solvency – The ability of a liquid to dissolve other substances; water is the best solvent known.
• Solvent – The liquid in which a solute dissolves; in the body, water.
• Surface tension – The tendency of water molecules at a surface to cling together and form a “skinThe body’s largest organ, providing protection and regulation.,” a result of cohesion.
• Suspension – A mixture in which particles are large enough to settle out unless stirred, such as blood cells in plasmaThe liquid component of blood..
• Synthesis reactions – Chemical reactions that join smaller molecules into a larger one (A + B → AB).

T-Z

• Thermal stability – Water’s resistanceThe opposition to airflow in the respiratory tract, influenced by airway diameter. to sudden temperature change, a result of its high heat capacityThe amount of heat needed to raise the temperature of a substance..
• Valence electrons – Electrons in the outer shell of an atom.
• Van der Waals forces – Weak attractions between molecules.
• Water – The universal solvent essential for life.

Carbs, Lipids, Proteins, and Nucleic Acids

A-D

• Activation energy – The minimum amount of energy required to start a chemical reaction.
• Active site – The specific region of an enzyme where a substrate binds and a reaction occurs.
• Alpha helix – A common spiral structure in proteins, stabilized by hydrogen bondsWeak attractions between hydrogen and electronegative atoms like oxygen or nitrogen..
• Amino acid – The building blocks of proteins, consisting of an amino group, carboxyl group, and side chain.
• Beta pleated sheet – A protein structure where strands of polypeptides fold into a pleated arrangement.
• Carbohydrate – Organic molecules composed of carbon, hydrogen, and oxygen, primarily used for energy.
• Carriers – Membrane proteins that transport substances across a cell membrane.
• Channels – Protein passages in the cell membrane that allow specific molecules to pass through.
• Cholesterol – A type of lipid that is a key component of cell membranes and precursor for steroid hormones.
• Coenzymes – Non-protein organic molecules that assist enzymesProteins that speed up chemical reactions in the body. in catalyzing reactions.
• Cofactor – A non-protein substance (often a metal ion) that helps enzymes function.
• Collagen – A structural protein found in connective tissues.
• Denature – The process in which a protein loses its shape and function due to heat or pH changes.
• Disaccharides – Carbohydrates composed of two monosaccharide units.
• DNA (Deoxyribonucleic acid) – The molecule that stores genetic information.

E-K

• Eicosanoids – Lipid molecules derived from fatty acids, involved in inflammation and cell signaling.
• Emulsion – A mixture of two immiscible liquids, such as oil and water.
• Enzyme-substrate specificity – The concept that enzymes bind only to specific substrates.
• Enzymes – Proteins that speed up chemical reactions in the body.
• Fatty acid – A long hydrocarbon chain with a carboxyl group, forming fats and oils.
• Fibrous proteins – Structural proteins with elongated shapes, such as collagenA structural protein in the dermis that provides strength and elasticity. and keratinA strong, fibrous protein that forms the structure of skin, hair, and nails..
• Globular proteins – Compact, spherical proteins that function in metabolismThe sum of all chemical reactions in the body. and transport.
• Glucose – A simple sugar that is the main source of energy for cells.
• Glycogen – A storage form of glucose found in animals.
• Glycolipids – Lipids with carbohydrateOrganic molecules composed of carbon, hydrogen, and oxygen, primarily used for energy. groups attached, important in cell recognition.
• Glycoproteins – Proteins with carbohydrate groups attached, involved in cell signaling.
• Keratin – A tough protein found in hair, nailsHard, keratinized structures that protect the fingertips and enhance fine motor skills., and skin.
• Kinases – Enzymes that transfer phosphate groups between molecules.

L-P

• Lactose – A disaccharide sugar found in milk.
• Lipids – Organic molecules including fats, oils, and steroids.
• Maltose – A disaccharide made of two glucose molecules.
• Monosaccharides – Simple sugars such as glucose and fructose.
• Nucleic acid – Large biomolecules (DNA & RNA) that store genetic information.
• Nucleotides – The building blocks of nucleic acids.
• Peptide bonds – Bonds that link amino acids in proteins.
• Phospholipids – Major components of cell membranes, consisting of a hydrophilic headRounded proximal end that fits into the acetabulum of the hip bone. and hydrophobic tail.
• Phosphorylation – The addition of a phosphate group to a molecule, often to activate it or store energy (ADP → ATP).
• Polypeptide – A chain of amino acids joined by peptide bondsBonds that link amino acids in proteins.; one or more fold to form a protein.
• Polysaccharides – Long chains of monosaccharides, such as starch, glycogenA storage form of glucose found in animals., and cellulose.
• Proteins – Large molecules made of amino acids with various functions in the body.
• Proteoglycans – Large molecules of protein with many carbohydrate chains attached; gel-forming components of connective tissue.

R-Z

• RNA (Ribonucleic acid) – The nucleic acid that carries DNA’s instructions to the ribosomesSmall structures responsible for protein synthesis, either free-floating or attached to the rough ER for protein synthesis.
• Saturated fatty acid – A fatty acid with no double bonds between carbon atoms.
• Starch – The storage form of glucose in plants; a dietary polysaccharide.
• Steroid – A lipid built on four fused carbon rings, such as cholesterolA lipid molecule that is a key component of cell membranes and a precursor for bile acids and steroi and the sex hormones.
• Substrate – The molecule an enzyme acts on.
• Sucrose – A disaccharide of glucose and fructose; table sugar.
• Triglyceride – A lipid made of glycerol and three fatty acids.
• Unsaturated fatty acid – A fatty acid with one or more double bonds.