Structure of Matter and Chemical Constituents of Cells

Vocabulary practice flashcards covering fundamental concepts of atomic structure, chemical bonding, reactions, pH, inorganic substances, and major organic macromolecules from Anatomy and Physiology Chapter 2.

Matter

Anything that takes up space and has mass (weight); it is composed of elements.

Elements

Fundamental substances composed of chemically identical atoms.

Bulk Elements

Chemical elements required by the human body in large amounts.

Trace Elements

Chemical elements required by the human body in small amounts.

Ultratrace Elements

Chemical elements required by the human body in very minute amounts.

Atom

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

Electron ($e^-$)

An extremely small subatomic particle with almost no weight that carries a negative electrical charge and is in constant motion around an atomic nucleus.

Proton ($p^+$)

A relatively large atomic particle that carries a single positive electrical charge and is found within an atomic nucleus.

Neutron ($n^0$)

A subatomic particle with about the same weight as a proton that is uncharged (electrically neutral) and found within an atomic nucleus.

Ion

A particle that is electrically charged because it has gained or lost one or more electrons.

Molecule

A particle formed by the chemical union of two or more atoms.

Atomic Number

The number of protons in the nucleus of one atom of a specific element.

Mass Number

The total number of protons plus neutrons in one atom.

Atomic Weight

The average mass numbers of the isotopes of an element.

Isotopes

Atoms with the same atomic number but different mass numbers due to a different number of neutrons.

Compound

A particle formed when two or more atoms of different elements chemically combine.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Ionic Bond

A chemical bond formed by the electrostatic attraction between a cation and an anion following an electron transfer.

Covalent Bond

A chemical bond formed when atoms share pairs of electrons.

Polar Molecule

A molecule with a slightly negative end and a slightly positive end resulting from unequal sharing of electrons in covalent bonds.

Hydrogen Bond

A weak attraction between the slightly positive end of one polar molecule and the slightly negative end of another polar molecule.

Reactants

The starting materials in a chemical reaction, consisting of atoms, ions, or molecules.

Products

Substances formed at the completion of a chemical reaction.

Synthesis Reaction

A chemical reaction in which two or more reactants combine to form a more complex structure ($A + B \rightarrow AB$).

Decomposition Reaction

A chemical reaction in which bonds are broken to form simpler chemical structures ($AB \rightarrow A + B$).

Exchange Reaction

A chemical reaction where bonds are broken and new bonds are formed to trade components ($AB + CD \rightarrow AD + CB$).

Reversible Reaction

A chemical reaction in which the products can react to reform the original reactants ($A + B \rightleftharpoons AB$).

Electrolytes

Substances that release ions when dissolved in water.

Acids

Electrolytes that dissociate in water to release hydrogen ions ($H^+$).

Bases

Substances that release ions (such as $OH^-$) that can combine with hydrogen ions.

Salts

Electrolytes formed by the reaction between an acid and a base.

pH Scale

A system measuring hydrogen ion ($H^+$) concentration in a solution, ranging from 0 to 14.

Buffers

Chemical systems that stabilize pH by acting as acids when pH is high and as bases when pH is low.

Organic Molecules

Molecules that contain both carbon and hydrogen, dissolve in water or organic liquids, and include carbohydrates, proteins, lipids, and nucleic acids.

Inorganic Molecules

Molecules that generally do not contain carbon and hydrogen, are usually smaller than organic molecules, and dissociate in water to form ions.

Carbohydrates

Water-soluble organic compounds containing C, H, and O in a ~2:1 H-to-O ratio that provide energy and building materials to cells.

Monosaccharides

Single sugar units, such as glucose and fructose, that serve as building blocks for complex carbohydrates.

Disaccharides

Double sugars formed by combining two monosaccharide units, such as sucrose and lactose.

Polysaccharides

Complex carbohydrates formed from long chains of monosaccharide units, such as glycogen and cellulose.

Triglycerides

Fats composed of 1 glycerol molecule and 3 fatty acid chains; the primary lipid stored for energy in the body.

Saturated Fatty Acid

A fatty acid chain containing only single bonds between carbon atoms, typically solid at room temperature and derived from animals.

Unsaturated Fatty Acid

A fatty acid chain containing one or more double bonds between carbon atoms, typically liquid at room temperature and derived from plants.

Phospholipids

Lipids containing 1 glycerol, 2 fatty acids, and 1 phosphate group, having a hydrophilic head and a hydrophobic tail; major structural component of cell membranes.

Steroids

Lipids composed of four connected rings of carbon atoms, utilized in hormone synthesis and cell membrane structure.

Amino Acids

The organic building blocks of proteins, consisting of an amino group, a carboxyl group, and a distinctive central R group.

Peptide Bond

A chemical bond formed between amino acid molecules to construct protein chains.

Protein Denaturation

A process that alters the solubility and three-dimensional shape of protein molecules, causing them to unfold or coagulate into a gel framework.

Nucleic Acids

Organic macromolecules (DNA and RNA) composed of nucleotides that store genetic information and direct protein synthesis.

Nucleotides

The structural building blocks of nucleic acids, each consisting of a 5-carbon sugar, a phosphate group, and a nitrogenous base.