Science Vocabulary Chapter 2 & 3

Chapter 2 Vocabulary

Element: Basic substance that cannot be broken down into simpler substances.
Compound: A substance formed when two or more elements chemically bond.
Atom: The smallest unit of an element retaining the properties of that element.
Radioactive Isotope: An atom with an unstable nucleus that emits radiation.
Atomic Number: Number of protons in an atom's nucleus, defining the element.
Electron Shells: Energy levels surrounding an atom's nucleus where electrons reside.
Valence Electrons: Electrons in the outermost shell, critical for chemical bonding.
Kinetic Energy: Energy of motion affecting atoms and molecules.
pH: Measure of acidity or alkalinity of a solution on a scale of 0-14.
Buffer: Solution that resists changes in pH when acids or bases are added.
Chemical Bonds: Forces holding atoms together in compounds.
Covalent Bond: Strong bond formed when atoms share electrons.
Molecule: A group of atoms joined by covalent bonds.
Polar Covalent Bond: Unequal sharing of electrons causing partial charges.
Nonpolar Covalent Bond: Equal sharing of electrons between atoms.
Ionic Bond: Chemical bond formed through the transfer of electrons.
Hydrogen Bond: Attraction between a hydrogen atom and an electronegative atom.
Van der Waals Force: Weak attractions between molecules from transient local partial charges.
Cohesion: Attraction between molecules of the same substance.
Adhesion: Attraction between molecules of different substances.
Specific Heat: Amount of heat required to change a substance's temperature.
Evaporative Cooling: Process where liquid evaporates, cooling the remaining liquid.
Heat of Vaporization: Energy needed for the liquid to become a gas.
Solvent: Substance that dissolves a solute, forming a solution.
Hydrophobic Substances: Molecules that repel water, not mixing with it.
Hydrophilic Substances: Molecules that attract water, mixing well with it.
Solute: Substance dissolved in a solvent to form a solution.
Surface Tension: The tendency of liquid surfaces to shrink and minimize surface area.
Capillary Action: Ability of liquid to flow in narrow spaces against gravity.
Ion: Atom or molecule with a net electric charge due to loss or gain of electrons.
Cation: Positively charged ion, formed by losing electrons.
Anion: Negatively charged ion, formed by gaining electrons.
Electronegativity: Measure of an atom's ability to attract shared electrons.

Chapter 3 Vocabulary

Organic Compound: Compounds primarily made of carbon atoms, often containing hydrogen, oxygen, and nitrogen.
Inorganic Compound: Compounds that typically do not contain carbon-hydrogen bonds.
Functional Group: Specific group of atoms responsible for the characteristic reactions of a compound.
ATP: Adenosine triphosphate, the primary energy carrier in cells.
Polymer: Large molecules composed of repeated subunits called monomers.
Monomer: Small molecular units that bond together to form polymers.
Dehydration Synthesis: Process of joining two molecules by removing water.
Hydrolysis: Chemical reaction that breaks down a compound by adding water.
Monosaccharide: Simple sugars, the building blocks of carbohydrates.
Disaccharide: Sugar formed by two monosaccharides.
Polysaccharide: Long-chain carbohydrate made up of multiple monosaccharides.
Triglycerides: Fat molecules composed of glycerol and three fatty acids.
Phospholipids: Major component of cell membranes, consisting of two fatty acids and a phosphate group.
Steroids: Lipid molecules characterized by a four-ring carbon structure.
DNA: Deoxyribonucleic acid, carrier of genetic information.
RNA: Ribonucleic acid, involved in protein synthesis and gene expression.
Amino Acid: Building blocks of proteins, containing an amino group, carboxyl group, and variable side chain.
Nucleotide: Basic unit of nucleic acids, composed of a sugar, phosphate group, and nitrogenous base.
Protein: Macromolecule composed of one or more long chains of amino acids, essential for structure and function in living organisms.
Nucleic Acid: Polymers made of nucleotide monomers; includes DNA and RNA.
Unsaturated Fats: Fats with at least one double bond in their fatty acid chains, typically liquid at room temperature.
Saturated Fats: Fats with no double bonds, solid at room temperature.
Pyrimidine: Type of nitrogenous base found in nucleic acids (e.g., cytosine, thymine).
Purine: Type of nitrogenous base (e.g., adenine, guanine) with a double-ring structure.
Gene: Segment of DNA that encodes for a protein or function.
Denaturation: Process of altering a protein's structure, often leading to loss of function.
Primary Structure: The linear sequence of amino acids in a protein.
Secondary Structure: The folding or coiling of the polypeptide chain into structures like alpha helices or beta sheets.
Tertiary Structure: The overall three-dimensional shape of a polypeptide.
Quaternary Structure: Structure formed by the combination of multiple polypeptide chains.
Peptide Bond: Covalent bond linking amino acids together in a protein.
Catalyst: Substance that increases the rate of a chemical reaction without being consumed.
Fatty Acid: Carboxylic acids with long hydrocarbon chains, important components of lipids.
Cellulose: Polysaccharide consisting of linear chains of glucose monomers; structural component in plant cell walls.
Glycogen: Storage form of glucose in animals, primarily found in liver and muscle tissues.
Starch: Storage form of glucose in plants, composed of amylose and amylopectin.
Glycosidic Linkage: Covalent bond linking monosaccharides to form disaccharides and polysaccharides.
Enzyme: Biological catalysts that speed up biochemical reactions.
Hydrocarbon: Organic compound consisting entirely of hydrogen and carbon.
Macromolecule: Large, complex molecules, including proteins, nucleic acids, carbohydrates, and lipids.