Chemistry Comes Alive - Key Terms (Human Anatomy & Physiology, 6th Edition)

Vocabulary flashcards covering key terms and definitions from the lecture on chemistry in human anatomy & physiology.

Solid

A state of matter with definite shape and definite volume.

Liquid

A state of matter with definite volume but adaptable shape.

Gas

A state of matter with neither definite shape nor definite volume; shape and volume are changeable.

Mechanical energy

Energy associated with motion and the interactions of objects; e.g., muscle contraction.

Electrical energy

Energy due to the movement of electrons or charge flow.

Chemical energy

Energy stored in chemical bonds that can be released during reactions.

Radiant (electromagnetic) energy

Energy traveling in waves, such as light and other forms of radiation.

Heat

Energy transfer due to a temperature difference; some energy may be dissipated as heat during conversions.

Element

A pure substance made of one type of atom with unique properties.

Atom

The basic unit of matter; the smallest unit of an element that retains its properties.

Atomic symbol

A one- or two-letter shorthand for an element (e.g., C for carbon).

Major elements

Elements that make up about 96% of body mass (e.g., O, C, H, N).

Trace elements

Elements required in very small amounts for normal body function.

Atomic number

Number of protons in an atom; equal to 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 the same number of protons but different numbers of neutrons.

Atomic weight

Approximate mass of an atom, based on the most abundant isotope.

Radioisotope

An isotope that undergoes spontaneous decay (radioactivity).

Planetary model

Model where electrons orbit the nucleus in fixed circular paths.

Orbital model

Model where electrons occupy regions around the nucleus where they are most likely found.

Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N)

Examples of major elements that comprise most body mass.

Phosphorus (P)

A major element; part of nucleic acids and ATP.

Calcium (Ca)

A major element; important for bones, muscle contraction, nerve function.

Molecule

Two or more atoms held together by chemical bonds; may be the same or different atoms.

Diatomic molecule

A molecule consisting of two atoms (e.g., O2).

Compound

Two or more different kinds of atoms bonded together.

Mixture

Two or more components physically intermingled, not chemically bonded.

Solution

A homogeneous mixture of components.

Solvent

Substance present in the greatest amount in a solution.

Solute

Substance(s) dissolved in the solvent.

Homogeneous

Mixtures with uniform composition throughout.

Heterogeneous

Mixtures with nonuniform composition; components are not evenly distributed.

Colloid

A suspension where particles are dispersed but not dissolved; appears homogeneous but is not.

Suspension

A mixture where larger particles settle out over time.

Percent concentration

Ratio expressed as a percentage; parts per hundred.

Molarity (M)

Moles of solute per liter of solution.

Parts per million (PPM)

A way to express very dilute concentrations (parts per 1,000,000).

Concentration

Measure of how much solute is mixed with a solvent in a solution.

Valence shell

Outermost electron shell that determines chemical reactivity.

Electron shells

Energy levels around the nucleus where electrons reside.

Chemically inert

Elements whose valence shell is complete and typically do not react easily.

Chemically reactive

Elements with incomplete valence shells that readily form bonds.

Covalent bonds

Bonds formed by sharing electron pairs between atoms.

Hydrogen bonds

Weaker bonds between polar molecules (e.g., water) that influence three‑dimensional structure.

Ionic bonds

Bond formed by transfer of electrons leading to charged ions that attract each other.

Octet rule

Atoms tend to gain, lose, or share electrons to have eight in their valence shell.

Redox reaction

Oxidation-reduction reaction; electrons are transferred between reactants.

Synthesis (combination) reaction

A+B→AB; two or more substances combine to form a new compound.

Decomposition reaction

AB→A+B; a compound breaks down into simpler substances.

Exchange reaction

A+B→A+BC; parts of molecules trade places.

Activation energy

The minimum energy required for a reaction to occur.

Exergonic reaction

Reactions that release energy; net energy of products is lower than reactants.

Endergonic reaction

Reactions that require input of energy; products have higher energy.

Chemical equilibrium

Dynamic state where forward and reverse reactions occur at equal rates.

Temperature effect

Higher temperature generally increases reaction rate.

Catalyst

Substance that speeds up a reaction without being consumed.

Enzyme

Biological catalyst; usually a protein that speeds up specific reactions.

Carbohydrate

Organic compound that provides cellular energy; contains C, H, O.

Lipid

Organic compound with C, H, O; includes fats, phospholipids, steroids; rich energy source.

Protein

Macromolecule made of amino acids; performs many functions (structure, enzymes, signaling).

Nucleic acid

Biomolecule (DNA/RNA) that stores and transfers genetic information.

Amino acid

Building block of proteins; contains amino and carboxyl groups.

Peptide bond

Bond linking amino acids in a protein chain.

Globular protein

Globular, compact proteins with functional roles (enzymes, antibodies).

Fibrous protein

Extended, strandlike proteins providing structural support (keratin, collagen).

Protein denaturation

Unfolding of a protein’s structure due to pH or temperature changes.

Chaperone (molecular chaperone)

Protein that assists other proteins in folding into functional shapes.

Apoenzyme

Protein portion of an enzyme without its nonprotein cofactor.

Cofactor

Nonprotein component (often a metal ion) needed for enzyme activity.

Holoenzyme

Whole active enzyme consisting of apoenzyme and cofactor.

Active site

Region of an enzyme where the substrate binds.

Nucleic acid

Biomolecule consisting of nucleotides; stores and transfers genetic information.

Nucleotide

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

Adenine (A)

Purine base in DNA/RNA; pairs with thymine (DNA) or uracil (RNA).

Guanine (G)

Purine base pairing with cytosine in DNA/RNA.

Cytosine (C)

Pyrimidine base pairing with guanine in DNA/RNA.

Thymine (T)

Pyrimidine base in DNA pairing with adenine.

Uracil (U)

Pyrimidine base in RNA pairing with adenine (replaces thymine in RNA).

DNA

Deoxyribonucleic acid; double-stranded, stores genetic information; replicated for cell division.

RNA

Ribonucleic acid; single-stranded; involved in protein synthesis; uses uracil instead of thymine.

Adenosine triphosphate (ATP)

Primary energy currency of the cell; adenine-containing nucleotide with three phosphates.

ATP-driven work

Cellular processes powered by ATP hydrolysis: transport work, mechanical work, and chemical work.