Human Anatomy & Physiology - Chapter 2: Chemistry Comes Alive

Vocabulary practice flashcards covering key chemical principles, subatomic structure, chemical bonding, reactions, inorganic/organic compounds, biomolecules, and bioenergetics from Chapter 2.

Matter

Anything that has mass and occupies space, existing in solid, liquid, or gas states.

Solid

A state of matter characterized by definite shape and definite volume, such as ice.

Liquid

A state of matter characterized by definite volume but changeable shape, such as fluid water.

Gas

A state of matter characterized by changeable shape and changeable volume, such as steam.

Kinetic Energy

Energy actively in action.

Potential Energy

Stored or inactive energy.

Chemical Energy

Energy stored within the bonds of chemical substances.

Electrical Energy

Energy resulting from the movement of charged particles.

Mechanical Energy

Energy directly involved in moving matter.

Radiant Energy

Energy that exhibits wavelike properties, such as visible light, ultraviolet light, and X-rays.

Element

A fundamental substance that cannot be broken down by ordinary chemical means.

Physical Properties

Properties of an element detectable with our senses or measurable, such as boiling point and texture.

Chemical Properties

Properties describing how atoms interact or bond with one another.

Atom

The structural building block for each element, composed of subatomic particles called neutrons, protons, and electrons.

Subatomic Particle Distribution in an Atom

Structure showing protons and neutrons clustered in the central nucleus with negatively charged electrons orbiting in outer shells.

Atomic Number

A number equal to the number of protons in an element's nucleus.

Atomic Symbol

A unique one- or two-letter chemical shorthand representing an element.

Atomic Weight

The average mass of protons and neutrons added together.

Major Elements of the Human Body

Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen (N), which together constitute about 96% of total body mass.

Solution

A homogeneous mixture in which components are equally distributed throughout, composed of a solvent and one or more solutes.

Solvent

The substance present in the greatest amount in a solution, usually a liquid.

Solute

The matter dissolved in a solvent, typically present in smaller amounts.

Molecule

Two or more atoms chemically bonded together, which can be of the same or different elements.

Compound

A substance composed of two or more different kinds of atoms chemically bonded together.

Octet Rule

The chemical principle stating that, except for the first shell which holds two electrons, atoms interact to acquire eight electrons in their valence shell.

Chemically Inert Elements

Elements with a fully occupied outermost energy level containing eight electrons (or two for helium), rendering them stable and unreactive.

Chemically Reactive Elements

Elements with an incomplete valence shell that tend to gain, lose, or share electrons to achieve stability.

Anion

An ion carrying a negative charge formed when an atom gains one or more valence electrons.

Cation

An ion carrying a positive charge formed when an atom loses one or more valence electrons.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions following an electron transfer.

Covalent Bond

A chemical bond formed by the sharing of two or more valence shell electrons between atoms.

Nonpolar Molecule

An electrically balanced molecule produced by the equal sharing of electrons between atoms.

Polar Molecule

A dipole molecule with distinct positive and negative charge ends, formed by unequal electron sharing.

Hydrogen Bond

An attractive intermolecular force between an electropositive hydrogen atom of one molecule and an electronegative atom of another.

Synthesis Reaction

An anabolic, energy-absorbing chemical reaction ($A + B \rightarrow AB$) where smaller particles bond to form larger molecules.

Decomposition Reaction

A catabolic, energy-releasing chemical reaction ($AB \rightarrow A + B$) in which bonds are broken to produce smaller molecules.

Exchange Reaction

A displacement chemical reaction ($AB + C \rightarrow AC + B$) involving both bond breaking and bond formation to rearrange components.

Exergonic Reaction

A chemical reaction that releases energy, typical of catabolic pathways.

Endergonic Reaction

A chemical reaction where products contain more potential energy than reactants, typical of anabolic pathways.

Catalyst

A substance that increases the rate of a chemical reaction without undergoing permanent chemical change or being consumed.

Enzyme

A biological catalyst that increases reaction speed by lowering the required activation energy.

Enzymatic Reaction Activation Energy

Energy profile comparison showing that reactions catalyzed by an enzyme require significantly less activation energy than reactions without an enzyme.

Inorganic Compounds

Chemical substances lacking carbon, including water, salts, acids, and bases.

Organic Compounds

Carbon-containing substances, such as carbohydrates, lipids, proteins, and nucleic acids, that are typically large and covalently bonded.

Salts

Ionic compounds that dissociate in water into cations other than $\text{H}^+$ and anions other than $\text{OH}^-$.

Acids

Electrolytes that act as proton donors, releasing hydrogen ions ($\text{H}^+$) in solution.

Bases

Electrolytes that act as proton acceptors, taking up hydrogen ions ($\text{H}^+$) in solution.

pH

The negative logarithm of hydrogen ion concentration ($[\text{H}^+]$) in moles per liter, measuring relative acidity or alkalinity.

Buffer

A mixture of chemical compounds that resists changes in pH by binding or releasing hydrogen ions.

Carbohydrates

Organic molecules composed of carbon, hydrogen, and oxygen in a ratio of $(\text{CH}_2\text{O})_n$, including sugars and starches.

Monosaccharides

Simple sugar monomers containing three to seven carbon atoms.

Disaccharides

Double sugars formed by joining two monosaccharides, which are too large to cross cell membranes.

Polysaccharides

Long branching polymers of linked monosaccharide units, such as glycogen and starch.

Lipids

Water-insoluble organic compounds composed of C, H, O, and sometimes P, including triglycerides, phospholipids, and steroids.

Triglycerides

Neutral fats composed of three fatty acid chains bound to a glycerol molecule, providing energy storage, insulation, and protection.

Phospholipids

Modified triglycerides consisting of glycerol, two fatty acids, and a phosphorus-containing group, possessing a polar head and nonpolar tail.

Steroids

Lipid molecules structured around four interlocking hydrocarbon rings, such as cholesterol.

Amino Acids

The 20 distinct organic building blocks of proteins, linked together by peptide bonds.

Fibrous Proteins

Water-insoluble, stable structural proteins consisting of extended strands with secondary structure, such as keratin and collagen.

Globular Proteins

Compact, water-soluble functional proteins folded into complex 3D shapes with specific active sites, such as enzymes and antibodies.

Protein Denaturation

The unfolding of a protein and loss of its active sites due to environmental changes in pH or temperature.

Nucleic Acids

Large organic molecules made of nucleotide building blocks containing C, O, H, N, and P, encompassing DNA and RNA.

DNA (Deoxyribonucleic Acid)

A double-stranded helical nucleic acid in the nucleus that stores genetic information and instructs protein synthesis.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid mostly active outside the nucleus that executes DNA instructions for protein synthesis.

ATP (Adenosine Triphosphate)

An adenine-containing RNA nucleotide with three phosphate groups that functions as the primary cellular energy carrier.