Chapter 02: Chemical Basis of Life

Vocabulary flashcards covering the key terms, definitions, and concepts from Chapter 2 on the chemical basis of anatomy and physiology.

Matter

Anything that takes up space and has mass, including solids, liquids, and gases.

Mass

The amount of matter present in an object.

Weight

The heaviness of an object due to the gravitational pull on its mass.

Chemistry

The branch of science concerned with the composition, properties, and interactions of matter.

Biochemistry

Biological chemistry, which studies physiological processes and disease.

Elements

The simplest types of matter with certain chemical properties; there are $92$ naturally occurring elements.

Compound

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

Atom

The smallest particle of an element that retains the properties of that element.

Bulk Elements

Elements required by the human body in large amounts, which include carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus.

Trace Elements

Elements required by the human body in small amounts, such as iron ($\text{Fe}$) and iodine ($\text{I}$).

Ultratrace Elements

Elements required by the human body in very minute amounts, such as arsenic ($\text{As}$).

Proton

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

Neutron

A relatively large, uncharged subatomic particle within an atomic nucleus that has about the same weight as a proton.

Electron

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

Ion

An electrically charged particle formed from an atom that 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 an atom of a specific element.

Mass Number

The total number of protons plus neutrons in one atom.

Isotopes

Atoms of the same element that have the same atomic number but different mass numbers due to containing different numbers of neutrons.

Radioactive Isotopes

Unstable isotopes that release energy or atomic fragments until they gain stability.

Iodine-131

A radioactive isotope used to destroy cancerous thyroid gland tissue because the thyroid is the only organ that actively transports and metabolizes iodine.

Ionizing Radiation

Radiation (alpha, beta, and gamma) with sufficient energy to remove electrons from atoms, resulting in the formation of ions.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic Bond

A strong chemical bond formed when ions of opposite electrical charges attract each other.

Covalent Bond

A strong chemical bond formed between atoms that share electrons.

Nonpolar Covalent Bond

A covalent bond in which electrons are shared equally between atoms with the same electronegativity.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally between atoms with different electronegativities, creating an unequal charge distribution.

Hydrogen Bond

A relatively weak attraction between the slightly positive hydrogen end of one polar molecule and the slightly negative nitrogen or oxygen end of a nearby polar molecule.

Reactants

The starting materials of a chemical reaction, which can be atoms, ions, or molecules.

Products

The substances formed at the end of a chemical reaction.

Synthesis Reaction

A chemical reaction in which a more complex chemical structure is formed from simpler substances.

Decomposition Reaction

A chemical reaction in which chemical bonds are broken to yield a simpler chemical structure.

Exchange Reaction

A chemical reaction in which chemical bonds are broken and new bonds are formed to trade components.

Reversible Reaction

A chemical reaction in which the products can change back into the original reactants.

Electrolytes

Substances that release ions in water and produce a solution capable of conducting an electric current.

Acids

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

Bases

Substances that release ions that can combine with hydrogen ions ($\text{H}^+$).

Salts

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

Acidemia

A condition in which blood pH drops to a range of $7.0$ through $7.3$.

Alkalemia

A condition in which blood pH rises to a range of $7.5$ through $7.8$.

Buffers

Chemicals that resist pH changes by binding and releasing ions to regulate pH levels.

Organic Molecules

Molecules containing carbon and hydrogen that dissolve in water or organic liquids and generally do not release ions.

Inorganic Molecules

Molecules that generally lack carbon and hydrogen, usually dissolve in water, and dissociate into ions to act as electrolytes.

Triglycerides

The most abundant lipids in the human body, consisting of 1 molecule of glycerol and 3 fatty acids, used primarily for cellular energy.

Saturated Fatty Acid

A fatty acid in which all carbon atoms are joined by single carbon-carbon bonds, typically solid at room temperature and of animal origin.

Unsaturated Fatty Acid

A fatty acid that contains one or more carbon-carbon double bonds, typically liquid at room temperature and of plant origin.

Phospholipid

A lipid composed of 1 glycerol, 2 fatty acids, and a phosphate group, forming the main structural component of cell membranes.

Steroid

A lipid structure consisting of 4 connected rings of carbon atoms, used to synthesize hormones and cell membrane components.

Peptide Bond

A bond formed between the amino group ($-\text{NH}_2$) of one amino acid and the carboxyl group ($-\text{COOH}$) of an adjacent amino acid.

Denaturation

A change in the secondary and tertiary structure of a protein caused by heat, radiation, pH changes, or chemicals.

Nucleotides

The building blocks of nucleic acids, each consisting of a sugar, a phosphate group, and an organic base.

Computerized Tomography (CT) Imaging

An imaging technique using an X-ray emitting device to create a 3-dimensional image of soft tissue densities.

Positron Emission Tomography (PET) Imaging

An imaging technique using positron-emitting radioactive isotopes to detect and visualize biochemical activity in tissues.