Seeley's Anatomy & Physiology - Chapter 2: Chemical Basis of Life

A complete set of vocabulary flashcards covering basic chemistry, chemical reactions, inorganic chemistry, and organic chemistry concepts from Chapter 2.

Matter

Anything that occupies space and has mass.

Mass

The amount of matter in an object, with the kilogram ($\text{kg}$) as its international unit.

Weight

The gravitational force acting on an object of a given mass.

Element

The simplest type of matter with unique chemical properties, composed of atoms of only one kind.

Atom

The smallest particle of an element that retains the chemical characteristics of that element.

Neutron

A subatomic particle located in the nucleus of an atom that carries no electrical charge.

Proton

A subatomic particle located in the nucleus of an atom that carries one positive charge.

Electron

A subatomic particle carrying one negative charge that occupies most of the volume of an atom within an electron cloud.

Nucleus (Atomic)

The central region of an atom formed by protons and neutrons.

Electron Cloud

The region surrounding the nucleus that occupies most of the volume of an atom where electrons are located.

Atomic Number

The number equal to the number of protons in each atom, which is also equal to the number of electrons.

Mass Number

The total number of protons plus the number of neutrons in an atom.

Isotope

One of two or more forms of the same element with the same number of protons and electrons but a different number of neutrons (e.g., ${}^1\text{H}$, ${}^2\text{H}$, ${}^3\text{H}$).

Atomic Mass

The average mass of naturally occurring isotopes of an element.

Valence Shell

The outermost energy level of an atom containing electrons that are shared or transferred during chemical bonding.

Electronegativity

The ability of an atom to attract electrons in a chemical bond.

Ion

An atom that has gained or lost an electron, acquiring an electrical charge.

Cation

A positively charged ion formed when an atom loses an electron.

Anion

A negatively charged ion formed when an atom gains an electron.

Ionic Bond

A chemical bond formed when electrons are transferred between atoms, creating oppositely charged ions that attract each other (e.g., $\text{Na}^+$ and $\text{Cl}^-$ forming $\text{NaCl}$).

Covalent Bond

A chemical bond formed when two or more atoms share electron pairs due to similar electronegativities.

Single Covalent Bond

A covalent bond formed when two atoms share one pair of electrons.

Double Covalent Bond

A covalent bond formed when two atoms share $4$ electrons (two pairs).

Nonpolar Covalent Bond

A covalent bond in which electrons are shared equally because the nuclei attract the electrons equally.

Polar Covalent Bond

A covalent bond in which electrons are not shared equally because one nucleus attracts the electrons more strongly than the other does.

Molecule

Two or more atoms chemically combined to form an independent unit (e.g., $\text{H}_2$).

Compound

A substance composed of two or more different types of atoms chemically combined (e.g., $\text{H}_2\text{O}$).

Molecular Mass

The mass determined by adding together the atomic masses of all atoms or ions in a molecule or compound.

Intermolecular Forces

Weak electrostatic attractions between oppositely charged parts of molecules, or between ions and molecules, that are weaker than chemical bonds.

Hydrogen Bond

A weak attraction occurring when the positively charged hydrogen atom of one molecule is attracted to the negatively charged oxygen, nitrogen, or fluorine atom of another molecule.

Solubility

The ability of one substance to dissolve in another.

Dissociation

The separation of cations and anions in an ionic compound when dissolved in water, surrounding each ion with water molecules.

Electrolytes

Solutions containing dissociated cations and anions in water that have the capacity to conduct an electric current.

Nonelectrolytes

Solutions containing dissolved molecules that do not dissociate into ions and do not conduct electricity.

Chemical Reaction

A process in which atoms, ions, molecules, or compounds interact to form or break chemical bonds.

Reactants

Substances that enter into a chemical reaction.

Products

Substances that result from a chemical reaction.

Metabolism

The collective term for the sum of all anabolic (synthesis) and catabolic (decomposition) reactions in the body.

Synthesis Reaction

A chemical reaction in which two or more reactants combine to form a new and larger product.

Anabolism

The collective term for all synthesis reactions in the body, which form chemical bonds and store energy.

Dehydration Reaction

A synthetic chemical reaction in which water is produced as a product.

Decomposition Reaction

A chemical reaction in which a large reactant is broken down to form smaller products.

Catabolism

The collective term for all decomposition reactions in the body, which break chemical bonds and release energy.

Hydrolysis Reaction

A decomposition reaction in which water is split into two parts that contribute to the formation of the products.

Reversible Reaction

A chemical reaction that can proceed either from reactants to products or from products to reactants.

Chemical Equilibrium

The state in a reversible reaction where the rate of product formation equals the rate of reactant formation.

Oxidation

The loss of an electron by a substance during a chemical reaction.

Reduction

The gain of an electron by a substance during a chemical reaction.

Oxidation-Reduction Reaction

A reaction in which the complete or partial loss of an electron by one substance is accompanied by the gain of that electron by another substance.

Potential Energy

Stored energy in chemical bonds that has the capacity to do work if released.

Kinetic Energy

Energy that actively does work and moves matter.

Mechanical Energy

Energy resulting from the position or movement of objects.

Chemical Energy

A form of potential energy stored within the chemical bonds of a substance.

Heat Energy

Energy that flows between objects of different temperatures, which is released during chemical reactions when energy is not captured in ATP.

Activation Energy

The minimum energy reactants must possess to initiate a chemical reaction.

Catalyst

A substance that increases the rate of a chemical reaction without being permanently changed or depleted.

Enzyme

A protein catalyst that increases the rate of chemical reactions by lowering the activation energy necessary for the reaction to begin.

Inorganic Chemistry

The study of substances that do not contain carbon-hydrogen bonds (e.g., water, oxygen, calcium phosphate, with exceptions such as $\text{CO}$, $\text{CO}_2$, and $\text{HCO}_3^-$).

Organic Chemistry

The study of carbon-containing substances.

Hydrophilic

Substances that are attracted to water ("water-loving").

Hydrophobic

Substances that are not attracted to water ("water-fearing").

Mixture

A combination of two or more substances that are physically but not chemically combined.

Suspension

A mixture in which materials separate unless constantly stirred (e.g., sand and water).

Colloid

A mixture characterized by the dispersal of tiny particles through a medium (e.g., milk).

Solution

A mixture of liquids, gases, or solids that are uniformly distributed and chemically combined.

Solvent

The component of a solution that dissolves the solute.

Solute

The component of a solution that is dissolved in the solvent.

Concentration

The measure of the number of particles of solute per volume of solution.

Osmolality

A measure reflecting the number of particles dissolved in $1\text{ kg}$ of water, typically measured in milliosmoles ($\text{mOsm}$) in the human body.

Acid

A proton donor or any substance that releases hydrogen ions ($\text{H}^+$).

Base

A proton acceptor or any substance that binds to or accepts hydrogen ions ($\text{H}^+$).

Salt

A compound consisting of a cation other than a hydrogen ion ($\text{H}^+$) and an anion other than a hydroxide ion ($\text{OH}^-$), such as $\text{NaCl}$.

Buffer

A solution of a conjugate acid-base pair in which acid and base components occur in similar concentrations to resist changes in pH.

pH Scale

A measure referring to the hydrogen ion concentration in a solution, where neutral is $7$, acidic indicates a higher $\text{H}^+$ concentration ($\text{pH} < 7$), and alkaline indicates a higher $\text{OH}^-$ concentration ($\text{pH} > 7$).

Isomers

Molecules that have the same chemical formula (same number and types of atoms) but differ in their 3-D structural arrangement.

Monosaccharides

Simple sugars, including six-carbon sugars (glucose, fructose, galactose) and five-carbon sugars, that serve as energy sources and structural building blocks.

Disaccharides

Carbohydrates formed when two simple sugars are bound together by a dehydration reaction (e.g., sucrose, lactose, maltose).

Polysaccharides

Long chains of many monosaccharides that function as storage molecules or structural components.

Glycogen

A storage polysaccharide formed by animals to store monosaccharides.

Starch

A storage polysaccharide formed by plants that serves as a food source of monosaccharides.

Cellulose

A structural polysaccharide formed by plants that acts as fiber (bulk) in the diet.

Triglycerides

Lipids composed of glycerol and three fatty acids that function in protection, insulation, and energy storage.

Saturated Fatty Acid

A fatty acid containing only single bonds in its carbon chain, producing a rigid structure.

Unsaturated Fatty Acid

A fatty acid containing one or more double bonds in its carbon chain, producing a more relaxed structure.

Trans Fats

Unsaturated fats that are artificially altered to be more saturated, posing the highest cardiovascular risk.

Phospholipids

Lipids containing a polar (hydrophilic) phosphate-containing region at one end and nonpolar (hydrophobic) fatty acid chains at the other, serving as major structural components of cell membranes.

Eicosanoids

Regulatory lipids derived from fatty acids that include thromboxanes, leukotrienes, and prostaglandins.

Steroids

Lipids characterized by four ring-like structures, including cholesterol, bile salts, estrogen, and testosterone.

Amino Acids

The organic building blocks of proteins.

Peptide Bond

A covalent bond formed between amino acids during protein synthesis.

Primary Structure

The specific linear sequence of amino acids in a protein chain.

Secondary Structure

The protein structure resulting from hydrogen bonding between amino acids, forming helices or pleated (folded) sheets.

Tertiary Structure

The large-scale folding of a protein due to interactions within the protein and its surrounding environment, which determines the shape of a domain.

Quaternary Structure

The protein structure resulting from the spatial association of two or more individual protein chains.

Active Site

The specific region on an enzyme's three-dimensional structure where reactants attach to undergo a reaction.

Lock-and-Key Model

A model of enzyme action where reactants fit into a rigid active site without changing shape.

Induced Fit Model

A model of enzyme action where the enzyme changes shape slightly to accommodate the shape of specific reactants.

Cofactors

Nonprotein substances (such as organic coenzymes) that combine with an active site to make nonfunctional enzymes functional.

Nucleotide

The structural building block of nucleic acids, composed of a five-carbon sugar (ribose or deoxyribose), a nitrogenous base, and a phosphate group.

Pyrimidines

Single-ring nitrogenous bases comprising cytosine, thymine (DNA only), and uracil (RNA only).