Chapter 2: The Chemical Basis of Life Flashcards

Vocabulary flashcards covering fundamental chemistry, chemical reactions, water properties, inorganic compounds, and major organic macromolecules from Chapter 2 of Seeley's Anatomy & Physiology (13th Edition).

Matter

Anything that occupies space and has mass.

Mass

The amount of matter in an object

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 that carries one negative charge and occupies most of the volume of an atom in an electron cloud.

Atomic Number

A number uniquely defining an element, equal to the number of protons (and electrons) in each atom.

Mass Number

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

Isotopes

Two or more forms of the same element that have the same number of protons and electrons but a different number of neutrons.

Molar Mass

The mass of one mole of a substance expressed in grams, which is equal to its atomic mass units.

Octet Rule

The chemical principle stating that atoms tend to react, share, or transfer electrons to achieve a full valence energy level of eight electrons.

Electronegativity

The ability of an atom's positively charged nucleus to attract electrons.

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 resulting from the transfer of electrons between atoms, creating oppositely charged ions that attract each other.

Nonpolar Covalent Bond

A covalent bond formed when electrons are shared equally between two nuclei because they attract the electrons equally.

Polar Covalent Bond

A covalent bond formed when electrons are shared unequally because one nucleus attracts the electrons more strongly than the other.

Molecule

Two or more atoms chemically combined to form an independent unit.

Compound

A substance composed of two or more different types of atoms chemically combined.

Intermolecular Forces

Weak electrostatic attractions between oppositely charged parts of molecules, or between ions and molecules.

Hydrogen Bond

An intermolecular attraction occurring when a positively charged hydrogen atom of one molecule is attracted to a 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 as they become surrounded by water molecules.

Electrolytes

Solutions formed by the dissociation of cations and anions in water that have the capacity to conduct an electric current.

Nonelectrolytes

Solutions formed by molecules that dissolve in water without dissociating, which do not conduct electricity.

Metabolism

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

Anabolism

The collective term for synthesis reactions in the body, where chemical bonds are formed and energy is stored.

Catabolism

The collective term for decomposition reactions in the body, where chemical bonds are broken and energy is released.

Dehydration Reaction

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

Hydrolysis Reaction

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

Equilibrium

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

Oxidation

The loss of an electron by an atom or molecule during a reaction.

Reduction

The gain of an electron by an atom or molecule during a reaction.

Potential Energy

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

Kinetic Energy

The energy of motion that actively performs work and moves matter.

Activation Energy

The minimum amount of energy that 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 required for the reaction to begin.

Inorganic Chemistry

The study of substances that lack carbon-hydrogen ($C-H$) bonds.

Organic Chemistry

The study of carbon-containing biological substances, excluding simple compounds like $CO$, $CO_2$, and $HCO_3^-$.

Cohesion

The attraction of one water molecule to another water molecule, generating surface tension.

Adhesion

The attraction of water molecules to other types of molecules.

Solvent

The liquid or substance in a solution that dissolves the solute.

Solute

The substance that is dissolved in a solvent to form a solution.

Suspension

A mixture containing materials that will separate unless constantly stirred, such as red blood cells in plasma.

Colloid

A mixture consisting of a dispersal of tiny particles through a medium that do not settle out, such as milk or cell interior.

Osmolality

A measure of concentration reflecting the number of particles dissolved in one kilogram of water.

Acid

A proton donor or any substance that releases hydrogen ions ($H^+$) in solution.

Base

A proton acceptor or any substance that binds to or accepts hydrogen ions ($H^+$) in solution.

Acidosis

A physiological condition occurring when blood pH drops below $7.35$, leading to nervous system depression.

Alkalosis

A physiological condition occurring when blood pH rises above $7.45$, leading to nervous system overexcitability.

Buffer

A solution of a conjugate acid-base pair that resists drastic changes in pH when acids or bases are added.

Isomers

Molecules that possess the exact same chemical formula but differ in their three-dimensional structure.

Monosaccharides

Simple sugar units such as glucose, fructose, and galactose that serve as energy sources and building blocks for complex carbohydrates.

Disaccharides

Carbohydrates composed of two simple sugars bound together via a dehydration reaction, such as sucrose, lactose, and maltose.

Polysaccharides

Long chains of monosaccharides that function as energy storage molecules (glycogen, starch) or structural bulk (cellulose).

Triglyceride

A lipid composed of one glycerol molecule bound to three fatty acid molecules through ester bonds.

Saturated Fatty Acid

A fatty acid carbon chain containing only single bonds, resulting in a rigid structure that is typically solid at room temperature.

Unsaturated Fatty Acid

A fatty acid carbon chain containing one or more double bonds, creating a relaxed structure that is typically liquid at room temperature.

Phospholipid

A structural membrane lipid consisting of a polar, hydrophilic phosphate head and nonpolar, hydrophobic fatty acid tails.

Eicosanoids

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

Steroids

Lipids characterized by a four-ring carbon structure, including cholesterol, bile salts, and reproductive hormones.

Peptide Bond

A covalent bond formed between two amino acids during protein synthesis through a dehydration reaction.

Denaturation

A change in the three-dimensional shape of a protein caused by breaking hydrogen bonds due to extreme heat or pH changes.

Primary Structure

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

Secondary Structure

The spatial arrangement of an amino acid chain resulting from hydrogen bonding, forming pleated sheets or helices.

Tertiary Structure

The large-scale folding of a protein domain determined by interactions with its environment and stabilized by disulfide bonds.

Quaternary Structure

The protein structure resulting from the association and interaction of two or more independent polypeptide subunits.

Active Site

The specific region on an enzyme where substrate molecules bind to undergo a chemical reaction.

Cofactors

Nonprotein substances required by nonfunctional enzymes to bind to the active site and make them functional.

Coenzymes

Organic cofactors, frequently derived from vitamins, that assist enzymes in executing catalytic activity.

Gene

A specific sequence of DNA bases that codes for the synthesis of RNA or a protein.

Adenosine Triphosphate (ATP)

The principal energy currency of the body, storing energy synthesized from nutrient breakdown and releasing it for cellular processes.