The Chemistry of Life: Basic Chemical Principles, Molecules, and Biological Compounds

Comprehensive vocabulary flashcards covering atomic structure, chemical bonding, chemical reactions, acid-base pH balance, water properties, and the primary classes of biological macromolecules from the lecture notes.

Matter

Anything that occupies space and has mass, which can exist in liquid, gaseous, or solid form and is composed of elements.

Element

A pure chemical substance that cannot be broken down further by natural forces, the smallest particles of which are atoms.

Chemical Compound

A substance formed by combinations of chemical elements that usually do not exist in free form in living cells.

Chemical Formula

The shorthand expression of a chemical compound, such as $NaCl$ for table salt.

Atomic Nucleus

The center of an atom, consisting of positively charged protons and uncharged neutrons.

Protons

Positively charged subatomic particles located in the atomic nucleus of an atom.

Neutrons

Subatomic particles without an electrical charge located in the atomic nucleus of an atom.

Electrons

Negatively charged subatomic particles that travel at high speed around the nucleus within orbitals or shells.

Atomic Number

A number indicating the total quantity of protons in the atomic nucleus of an atom.

Atomic Weight (Atomic Mass)

The value equal to the sum of protons and neutrons in an atom.

Valence Electrons

Electrons located in the outermost shell of an atom that are available for chemical bonding and determine what kind of bonds can form.

Isotopes

Atoms with the same number of protons but a different number of neutrons, resulting in an identical atomic number but a different atomic weight.

Radioactivity

The release of energy and matter that results from changes and an imbalance of energy within the nucleus of an atom.

Ions

Electrically charged atoms, molecules, or subatomic particles formed when one or more valence electrons are transferred from one atom to another.

Cations

Positively charged ions that lose one or more electrons and migrate toward the negative pole (cathode) in an electric field.

Anions

Negatively charged ions that gain one or more electrons and migrate toward the positive pole (anode) in an electric field.

Electrolyte

A substance that dissociates into free ions when dissolved in a solvent like water, enabling the resulting ionic solution to conduct an electric current.

Homeostasis

The maintenance of a precise internal balance of electrolytes required to regulate an organism's osmotic gradient, hydration, blood pH, and neuromuscular function.

Molecule

A chemical unit consisting of two or more atoms linked together by chemical bonds formed by their valence electrons.

Functional Groups

Specific groups of atoms that consistently form characteristic reactive entities within chemical compounds.

Nonpolar Covalent Bond

A chemical bond resulting from the equal sharing of electrons between atoms, yielding an electrically balanced, nonpolar molecule.

Polar Covalent Bond

A covalent bond formed between atoms of different-sized elements where electrons are unequally shared and pulled closer to the larger atom.

Coordinate Covalent Bond

A type of covalent bond formed when both shared electrons are provided by only one of the participating atoms.

Ionic Bond

A chemical bond formed when one or more electrons are transferred from one atom to another, binding the resulting cations and anions by electrostatic attraction.

Hydrogen Bond

A weak chemical attraction having about $5\%$ of the strength of a covalent bond, formed between a slightly positive hydrogen atom and a slightly negative oxygen or nitrogen atom.

Van der Waals Forces

The weakest intermolecular attractive forces, which diminish inversely with the seventh power of the interatomic distance and determine molecular specificity.

Dehydration Synthesis (Condensation)

An anabolic, energy-requiring reaction that produces a polymer from monomers by removing a hydroxyl group ($OH^-$) from one monomer and a hydrogen ($H^+$) from another to form water.

Hydrolysis (Decomposition)

A catabolic, exergonic reaction that breaks down large polymers into their monomer units through the chemical addition of water.

Anabolism

The cellular metabolic process of synthesizing new, complex compounds from simpler molecules using energy provided by catabolism.

Catabolism

The breakdown of complex nutrient molecules into smaller monomers during cellular metabolism to release potential energy.

Endergonic Reactions

Chemical reactions that require an input of energy, such as the dehydration synthesis of nutrient molecules during anabolism.

Exergonic Reactions

Chemical reactions that yield or release energy, such as hydrolysis reactions occurring during catabolism.

Oxidation

A chemical reaction involving the loss of electrons by an atom or molecule, resulting in a more positive oxidation state.

Reduction

A chemical reaction involving the gain of electrons by an atom or molecule, resulting in a more negative oxidation state.

Exchange Reactions

Chemical reactions in which components are transferred and rearranged into a different molecular combination while preserving the same overall components.

Acid

A molecule that acts as a proton donor by releasing hydrogen ions ($H^+$) into an aqueous solution.

Base

A molecule that acts as a proton acceptor by combining with and removing hydrogen ions ($H^+$) from a solution, often releasing hydroxyl ions ($OH^-$).

pH Scale

A logarithmic measurement scale running from $0$ to $14$ that represents the negative logarithm of the hydrogen ion concentration of a solution, with $7$ designated as neutral.

Buffer

A system of molecules and ions that stabilizes the pH of a solution by absorbing hydrogen or hydroxyl ions to resist changes in acidity or alkalinity.

Normal Salts

Electrolyte compounds formed by reactions between acids and bases or metals and acids that dissociate in water without releasing hydrogen or hydroxyl ions.

Cohesion

The property of water molecules sticking to one another due to the rapid breaking and reforming of hydrogen bonds, giving rise to high surface tension.

Solvent

A liquid medium, such as water, capable of dissolving other substances (solutes).

Solute

A substance dissolved in a liquid solvent to produce a solution.

Solution

A uniform mixture produced when one or more solutes dissolve and dissociate in a solvent.

Isotonic

A condition in which the extracellular solute concentration and osmotic pressure equal those inside the cell, producing no change in cell volume.

Hypertonic

A condition in which the extracellular solute concentration is higher than inside the cell, causing a net efflux of water and cellular shrinkage (crenation).

Hypotonic

A condition in which the extracellular solute concentration is lower than inside the cell, driving net water uptake that causes cell swelling and potential lysis.

Hydration Spheres

Concentric clusters of oriented polar water molecules that surround ions and polar atoms, conferring water solubility.

Hydrophilic

Water-loving substances that possess polar areas or charges enabling them to form hydration spheres and dissolve in water.

Hydrophobic

Water-repelling substances composed of nonpolar covalent bonds that are incapable of forming hydration spheres and are insoluble in water.

Monosaccharides

Simple sugar monomers containing three to seven carbon atoms and an aldehyde or keto group, exhibiting an elemental ratio of $2:1:2$ ($C:H:O$).

Disaccharides

Carbohydrates composed of two monosaccharide molecules joined together with the loss of a water molecule, including sucrose, lactose, and maltose.

Polysaccharides

Large carbohydrate polymers formed by joining many monosaccharides, serving functions in energy storage (starch, glycogen) or cellular structures (cellulose).

Amino Acids

The $20$ naturally occurring building blocks (monomers) of proteins, each consisting of an amino group ($NH_2$), a carboxyl group ($COOH$), and a variable $R$ group.

Protein Denaturation

The loss of a protein's characteristic three-dimensional shape and biological catalytic activity induced by heat, extreme pH, salts, radiation, or heavy metals.

Conjugated Proteins

Proteins that are combined with nonprotein organic or inorganic molecules, such as glycoproteins, lipoproteins, nucleoproteins, and phosphoproteins.

Triglycerides

Neutral lipids composed of a glycerol molecule bonded to three fatty acid chains that function as long-term energy storage ($9.3\,kcal/g$).

Phospholipids

Lipid molecules consisting of glycerol, two nonpolar hydrophobic fatty acid tails, and a polar hydrophilic phosphate head, forming membrane bilayers.

Steroids

Lipid molecules structured around a carbon skeleton consisting of four fused rings with attached functional groups.

Prostaglandins

Local lipid hormones composed of a fatty acid and a cyclic hydrocarbon group that regulate localized physiological responses such as blood clotting and inflammation.

Nucleotides

The structural monomers of nucleic acids, each composed of a pentose sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous base.

Complementary Base Pairing

The precise hydrogen bonding between specific nitrogenous bases in nucleic acids: adenine with thymine (or uracil in RNA) and guanine with cytosine.

Adenosine Triphosphate (ATP)

The primary cellular energy carrier, composed of ribose, adenine, and three phosphate groups joined by high-energy bonds.