Chapter 2: Chemistry Comes Alive

Vocabulary practice flashcards covering fundamental concepts in anatomy, physiology, atomic chemistry, chemical bonding, reactions, and biological macromolecules from Chapter 2 lecture notes.

Principle of Complementarity of Structure and Function

The anatomical and physiological concept stating that what a body part can do depends on its specific shape and structural setup.

Homeostatic Control System

A mechanism that maintains stable internal conditions through interactions among a stimulus, receptor (monitors environment), afferent pathway, control center (determines set point), efferent pathway, and effector (produces response).

Levels of Structural Organization

The hierarchy of complex structures working together to keep the body alive, progressing from chemical level (atoms and molecules), cellular level, tissue level, organ level, organ system level, to organismal level.

Atom

The smallest unit of matter that retains the chemical properties of an element, composed of protons, neutrons, and electrons.

Atomic Number

The number of protons in an atom's nucleus, which determines the element and equals its total number of electrons in a neutral atom.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Isotope

A structural variation of an atomic element that has the same atomic number (protons) but a different mass number due to a differing number of neutrons.

Radioisotope

An unstable, heavier isotope that spontaneously decomposes to achieve a more stable form, emitting radiation and used in medical diagnostic tools like PET scans.

Solution

A homogeneous mixture containing very tiny solute particles dissolved in a solvent that do not settle out or scatter light.

Colloid

A heterogeneous mixture containing intermediate-sized solute particles that scatter light but do not settle out, often undergoing sol-gel transformations.

Suspension

A heterogeneous mixture containing large solute particles that settle out of the fluid over time and may scatter light.

Serum

The liquid component of blood remaining after blood coagulation occurs, which is devoid of clotting factors like fibrinogen ($\text{Serum} = \text{Plasma} - \text{Fibrinogen}$).

Octet Rule

The principle stating that the chemical reactivity of atoms is driven by their desire to fill their valence shell with 8 electrons.

Ionic Bond

A chemical bond formed by the complete transfer of valence electrons from one atom to another, producing oppositely charged ions that attract each other.

Anion

An atom or molecule that has gained one or more electrons (acting as an electron acceptor), resulting in a net negative charge.

Cation

An atom or molecule that has lost one or more electrons (acting as an electron donor), resulting in a net positive charge.

Covalent Bond

A chemical bond formed when two atoms share two or more valence shell electrons.

Nonpolar Covalent Bond

A type of covalent bond where electrons are shared equally between atoms, resulting in a balanced, electrically neutral molecule.

Polar Covalent Bond

A covalent bond formed by unequal electron sharing between two atoms with differing electronegativities, producing a dipole molecule with partial positive and negative poles.

Hydrogen Bond

A weak attractive force between an electropositive hydrogen atom of one polar molecule and an electronegative atom of another molecule.

Synthesis Reaction

An anabolic chemical reaction in which smaller atoms or molecules combine to form a larger, more complex molecule ($A + B \rightarrow AB$).

Decomposition Reaction

A catabolic chemical reaction in which bonds are broken within a larger molecule, yielding smaller, less complex molecules ($AB \rightarrow A + B$).

Exchange Reaction

A chemical reaction involving both synthesis and decomposition, where bonds are made and broken to exchange components ($AB + CD \rightarrow AD + CB$).

Oxidation-Reduction Reaction

A chemical reaction (redox) in which an electron donor is oxidized by losing electrons and an electron acceptor is reduced by gaining electrons.

Exergonic Reaction

A chemical reaction that yields a net release of energy, where the potential energy of the products is less than that of the reactants.

Endergonic Reaction

An anabolic chemical reaction that absorbs energy from its surroundings, resulting in products with higher potential energy than the reactants.

Electrolyte

A substance (such as a salt, acid, or base) that ionizes in water and is capable of conducting electrical currents.

pH Scale

A logarithmic measurement scale of hydrogen ion concentration in a solution, defined as $\text{pH} = -\log[H^+]$.

Monosaccharide

A simple sugar containing 3 to 7 carbon atoms represented by the general formula $(CH_2O)_n$, serving as the monomeric building block of carbohydrates.

Disaccharide

A double sugar consisting of two linked monosaccharide rings, which must be hydrolyzed into simple sugars before absorption across cell membranes.

Polysaccharide

A large, insoluble polymer consisting of long chains of linked simple sugars, used for carbohydrate storage in plants (starch) and animals (glycogen).

Triglyceride

A neutral lipid composed of three fatty acid chains bonded to a single glycerol molecule in a 3:1 ratio, providing long-term energy storage, insulation, and organ protection.

Saturated Fatty Acid

A fatty acid chain in which all carbon-carbon bonds are single covalent bonds, maxing out hydrogen atom capacity and enabling tight packing into solids at room temperature.

Unsaturated Fatty Acid

A fatty acid chain containing one or more double carbon bonds, causing chain kinks that prevent close packing and keep the fat liquid at room temperature.

Phospholipid

A modified triglyceride featuring a glycerol backbone, two nonpolar fatty acid tails, and a polar, phosphorus-containing head region.

Steroid

A class of lipids characterized by four interlocking hydrocarbon rings, serving as the structural basis for cholesterol, vitamin D, sex hormones, and bile salts.

Eicosanoid

A lipid molecule derived from 20-carbon arachidonic acid found in cell membranes, including biologically vital prostaglandins that mediate inflammation and blood clotting.

Amino Acid

The monomeric building block of proteins, consisting of an amine group ($-NH_2$), an acid group ($-COOH$), and a unique variable R group.

Peptide Bond

A covalent bond formed via dehydration synthesis that connects the acid group of one amino acid to the amine group of another.

Primary Structure

The linear sequence of amino acids linked together in a polypeptide chain.

Secondary Structure

The local folding of a primary amino acid chain into coiled alpha-helices or accordion-like beta-pleated sheets, held together by hydrogen bonds.

Tertiary Structure

The three-dimensional folding of secondary protein structures into a compact, globular shape stabilized by intramolecular covalent and hydrogen bonds.

Quaternary Structure

The complex protein level formed when two or more distinct polypeptide chains, each with its own tertiary structure, unite to form a functional macromolecule.

Fibrous Protein

An insoluble, strandlike structural protein providing mechanical support and tensile strength to tissues, such as keratin, elastin, and collagen.

Globular Protein

A compact, spherical, water-soluble, and chemically active functional protein possessing active sites, such as enzymes, antibodies, and hormones.

Denaturation

The unfolding process in which globular proteins lose their functional three-dimensional shape and active site activity due to environmental stress like high heat or acidic pH.

Enzyme

A biological catalyst composed of globular protein that accelerates chemical reactions by lowering activation energy without being consumed.

Activation Energy

The initial amount of energy required to break chemical bonds and initiate a chemical reaction.

Deoxyribonucleic Acid (DNA)

A double-stranded helical nucleic acid containing deoxyribose sugar and A, T, G, C bases that resides in the nucleus and directs protein synthesis and genetic inheritance.

Ribonucleic Acid (RNA)

A single-stranded nucleic acid containing ribose sugar and A, U, G, C bases that resides in the cytoplasm and carries out genetic instructions for protein synthesis.