Chemical Level of Organization Flashcards

Comprehensive vocabulary flashcards covering atomic structure, chemical bonding, reactions, water properties, pH regulation, and organic biological macromolecules based on lecture notes.

Matter

Anything that takes up space and has mass.

Mass

The quantity of material in matter, which on Earth is equivalent to weight.

Atom

The smallest stable unit of matter, composed of protons, neutrons, and electrons.

Proton

A subatomic particle located in the atomic nucleus that possesses a positive electrical charge.

Neutron

An electrically neutral (uncharged) subatomic particle located in the atomic nucleus.

Electron

A subatomic particle with a negative electrical charge that exists in the electron cloud surrounding the nucleus and is much smaller than protons or neutrons.

Atomic Number

The total number of protons contained within an atom.

Mass Number

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

Element

A pure substance composed entirely of atoms that share the exact same atomic number.

Isotopes

Atoms of the same element that have identical numbers of protons but different numbers of neutrons, resulting in different mass numbers.

Valence Shell

The outermost energy level of an atom; unfilled valence shells make atoms chemically reactive, whereas full valence shells make them inert.

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.

Compound

A chemical substance made up of atoms of two or more different elements combined in a fixed proportion.

Molecule

A chemical structure consisting of atoms of one or more elements held together by covalent bonds.

Ionic Bond

A chemical bond created by the electrical attraction between oppositely charged ions (cations and anions) following an electron transfer.

Covalent Bond

A chemical bond formed when atoms share pairs of electrons to complete their outer energy shells.

Nonpolar Molecule

A molecule formed by covalent bonds where electrons are shared equally between atoms, leaving no net electrical charge.

Polar Molecule

A molecule formed by polar covalent bonds involving unequal sharing of electrons, resulting in slightly positive and slightly negative regions.

Hydrogen Bond

A weak attraction between the slight positive charge on a hydrogen atom in a polar molecule and a slight negative charge on an atom in another polar molecule.

Surface Tension

A physical property of liquid water caused by hydrogen bonding between water molecules that acts as a barrier keeping small objects from entering the liquid.

Metabolism

The sum total of all chemical reactions taking place in the body at any given moment, encompassing both catabolism and anabolism.

Catabolism

The collective term for decomposition reactions in the body that break covalent bonds and release kinetic energy.

Anabolism

The collective term for synthesis reactions in the body that form new chemical bonds and require an input of energy.

Decomposition Reaction

A chemical reaction that breaks a larger molecule into smaller fragments (represented as $\text{AB} \rightarrow \text{A} + \text{B}$).

Hydrolysis

A specific decomposition reaction in which a water molecule is consumed to break a chemical bond within a complex molecule.

Synthesis Reaction

A chemical reaction that assembles smaller molecules into larger, more complex molecules by forming new chemical bonds (represented as $\text{A} + \text{B} \rightarrow \text{AB}$).

Dehydration Synthesis

A synthesis reaction (condensation) in which smaller molecules are joined together to form a complex molecule through the removal of a water molecule.

Chemical Equilibrium

The state in a reversible chemical reaction where the rates of the forward and reverse reactions proceed in balance.

Activation Energy

The minimum amount of energy required to activate reactants and initiate a chemical reaction.

Enzyme

A biological protein catalyst that accelerates chemical reactions in cells by lowering their required activation energy.

Exergonic Reaction

A chemical reaction that results in an overall net release of energy.

Endergonic Reaction

A chemical reaction in which more energy is required to initiate the reaction than is ultimately released.

Metabolites

All the chemical substances that are synthesized or decomposed by enzymatic reactions within the body.

Nutrients

Essential metabolites required by the body that are normally obtained directly from the diet.

Organic Compounds

Chemical compounds that always contain carbon and hydrogen as their primary structural basis.

Inorganic Compounds

Chemical compounds that generally do not contain carbon and hydrogen atoms as their primary structural elements.

Monomer

A simple molecule that can be chemically bonded to other identical or similar molecules to form a larger polymer.

Polymer

A large macromolecule composed of repeating monomer units joined together by dehydration synthesis.

Hydration Sphere

A surrounding sheath of oriented water molecules that encapsulates an ion or polar molecule in aqueous solution.

Hydrophilic

Molecules with polar covalent bonds that readily attract water molecules and dissolve in aqueous solutions.

Hydrophobic

Nonpolar molecules lacking positive or negative poles that do not readily interact with water and fail to dissolve in aqueous solutions.

Electrolytes

Soluble inorganic substances whose ions dissociate in water and are capable of conducting an electrical current.

Colloid

A solution containing dispersed proteins or other large molecules that remain suspended indefinitely (e.g., cell cytosol).

Suspension

A heterogeneous mixture containing large particles that will settle out of solution if left undisturbed (e.g., whole blood).

pH

The negative logarithm of hydrogen ion concentration in body fluids, expressed on a scale from 0 to 14.

Acid

A solute that dissociates in solution to release hydrogen ions ($H^+$), acting as a proton donor.

Base

A solute that removes hydrogen ions ($H^+$) from solution, acting as a proton acceptor and often releasing hydroxide ions ($OH^-$).

Acidosis

An abnormal physiological condition characterized by blood pH falling below 7.35.

Alkalosis

An abnormal physiological condition characterized by blood pH rising above 7.45.

Salt

An inorganic ionic compound consisting of any cation except $H^+$ and any anion except $OH^-$.

Buffers

Compounds that stabilize the pH of a solution by removing or replacing hydrogen ions ($H^+$).

Functional Group

A specialized arrangement of atoms attached to an organic molecule that imparts specific chemical properties to that molecule.

Amino Group

A functional group ($-\text{NH}_2$) that acts as a base by accepting $H^+$ depending on pH and can form bonds with other molecules.

Carboxyl Group

A functional group ($-\text{COOH}$) that acts as an acid by releasing $H^+$ to become $R-\text{COO}^-$.

Hydroxyl Group

A functional group ($-\text{OH}$) that affects solubility via hydrogen bonding with water molecules and links molecules through dehydration synthesis.

Phosphate Group

A functional group ($-\text{PO}_4^{2-}$) that links molecules to form larger structures and can store energy.

Monosaccharide

A simple sugar carbohydrate containing three to seven carbon atoms with carbon, hydrogen, and oxygen in an approximate ratio of 1:2:1.

Isomers

Molecules that possess identical molecular formulas but different structural arrangements of their atoms (e.g., glucose and fructose).

Glycogen

A highly branched polysaccharide composed of glucose chains that serves as glucose storage in animal cells.

Amino Acids

The 20 monomeric building blocks of proteins, consisting of a central carbon atom bound to a hydrogen atom, an amino group, a carboxyl group, and a variable R side chain.

Peptide Bond

A covalent bond formed via dehydration synthesis connecting the carboxyl group of one amino acid to the amino group of another.

Primary Structure

The linear sequence of amino acids along a single polypeptide chain.

Secondary Structure

The protein shape resulting from hydrogen bonding along a single polypeptide chain, giving rise to an alpha-helix or beta sheet.

Tertiary Structure

The complex 3-D coiling and folding of a single polypeptide chain, driven primarily by interactions with surrounding water and R groups.

Quaternary Structure

The final protein complex formed by the structural interaction of multiple individual polypeptide chains.

Denaturation

A structural change in a protein's tertiary or quaternary arrangement caused by extreme conditions (such as high heat), resulting in loss of shape and function.

Active Site

A specific pocket or region of an enzyme determined by its tertiary or quaternary structure where substrate molecules bind.

Substrates

The specific reactant molecules that bind to an enzyme's active site to yield specific products.

Fatty Acids

Lipid molecules consisting of long carbon chains with attached hydrogens, terminating in a hydrophilic carboxyl head and a hydrophobic tail.

Steroids

Large lipid molecules sharing a characteristic framework of four carbon rings, including cholesterol and sex hormones.

Phospholipid

A diglyceride lipid bound to a phosphate group and a nonlipid group, possessing a hydrophilic head and two hydrophobic tails.

Micelles

Spherical droplets formed in water by amphipathic lipids (like phospholipids), where hydrophilic heads face outward toward water and hydrophobic tails face inward.

Nucleotide

The monomer building block of nucleic acids, consisting of a nitrogenous base, a pentose sugar (ribose or deoxyribose), and a phosphate group.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid containing deoxyribose sugar and nitrogenous bases (A, T, C, G) that stores genetic information for controlling protein synthesis.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid containing ribose sugar and nitrogenous bases (A, U, C, G) that performs protein synthesis as directed by DNA.