Chemical Level of Organization Flashcards

Vocabulary flashcards covering the Chemical Level of Organization, including atomic structure, subatomic particles, chemical bonding, reactions, water properties, pH, and major classes of organic molecules.

Matter

Anything that occupies space and has mass, existing in solid, liquid, or gaseous states.

Energy

The ability to do work; it does not occupy space and has no mass.

Atom

The smallest stable unit of matter.

Subatomic Particles

The fundamental particles that compose an atom: protons, neutrons, and electrons.

Proton

A positively charged subatomic particle located in the nucleus of an atom with a charge of $+1$ and a mass of $1$ unit; attributed in notes to James Chadwick.

Neutron

A neutral subatomic particle located in the nucleus of an atom with no charge ($0$) and a mass of $1$ unit; attributed in notes to Eugene Goldstein.

Electron

A negatively charged subatomic particle that moves around the electron cloud or orbital shell, with a charge of $-1$ and light mass; discovered by John Joseph Thomson.

Atomic Number

The number of protons in the nucleus of an atom, which determines the element.

Mass Number

The sum of the number of protons and neutrons in the nucleus of an atom.

Element

A pure substance that contains only one type of atom and cannot be broken down by chemical means.

Isotopes

Different versions of an element that have the same number of protons but different mass numbers due to varying numbers of neutrons.

Valence Shell

The outermost electron shell of an atom, containing electrons that determine the atom's bonding behavior and reactivity.

Energy Levels

Concentric electron shells (such as K, L, M, N) surrounding the nucleus that hold electrons, filling in order from lower to higher shells.

Ionic Bond

A chemical bond formed by the electrostatic attraction between positively charged cations and negatively charged anions.

Cation

A positively charged ion formed when an atom (the electron donor) loses one or more electrons.

Anion

A negatively charged ion formed when an atom (the electron acceptor) gains one or more electrons.

Covalent Bond

A strong chemical bond formed by the sharing of one or more pairs of electrons between atoms.

Nonpolar Covalent Bond

A covalent bond involving the equal sharing of electrons between atoms, resulting in a balanced molecule.

Polar Covalent Bond

A covalent bond involving unequal sharing of electrons, creating partial positive and negative charges on the molecule.

Hydrogen Bond

A weak bond based on electrical attraction between the slightly positive portion of a polar molecule and the slightly negative portion of another polar molecule.

Molecule

A general term for any atoms that are connected by chemical bonds.

Compound

A substance formed when two or more atoms of different elements are joined by chemical bonds.

Decomposition Reaction (Catabolism)

A chemical reaction that breaks chemical bonds, represented as $AB \rightarrow A + B$.

Hydrolysis

A decomposition reaction in which chemical bonds are broken through the addition of water ($A-B + H_2O \rightarrow A-H + HO-B$).

Synthesis Reaction (Anabolism)

A chemical reaction that forms new chemical bonds, represented as $A + B \rightarrow AB$.

Dehydration Synthesis

A synthesis reaction in which chemical bonds are formed along with the removal of a water molecule ($A-H + HO-B \rightarrow A-B + H_2O$).

Exchange Reaction

A reaction involving initial decomposition followed by synthesis, represented as $AB + CD \rightarrow AD + CB$.

Enzyme

A protein catalyst that lowers the activation energy of a chemical reaction to speed up the reaction rate.

Activation Energy

The minimum amount of energy needed to get a chemical reaction started.

Substrate

The specific reactant molecule or substance upon which an enzyme acts.

Mechanism of Enzyme Activity

The process by which a substrate binds to an enzyme's active site to form an enzyme-substrate complex, converting the substrate into products.

Inorganic Compounds

Molecules that are not based on carbon and hydrogen, such as carbon dioxide, oxygen, water, inorganic acids, bases, and salts.

Organic Compounds

Carbon- and hydrogen-based molecules containing a carbon backbone and functional groups, covalently bonded.

Solution

A uniform mixture consisting of two or more substances.

Solvent

The liquid medium in which atoms, ions, or molecules are dissolved or dispersed.

Solute

The dispersed substance that is dissolved in a solvent.

Suspension

A heterogeneous mixture containing particles that will settle out if left undisturbed.

Hydrophilic

Water-loving molecules, including ions and polar substances, that readily interact with water.

Hydrophobic

Water-fearing molecules, such as nonpolar molecules, fats, and oils, that do not interact with water.

pH

A measure of the concentration of hydrogen ions ($H^+$) in a solution, expressed on a scale from $0$ to $14$.

Acidic pH

A pH value lower than $7.0$, indicating a high concentration of hydrogen ions ($H^+$).

Basic (Alkaline) pH

A pH value higher than $7.0$, indicating a low concentration of hydrogen ions ($H^+$).

Carbohydrates

Organic molecules containing carbon, hydrogen, and oxygen in a $1:2:1$ ratio, serving as a primary energy source.

Monosaccharide

A simple sugar containing $3$ to $7$ carbon atoms, such as glucose, fructose, and galactose.

Disaccharide

A sugar formed when two monosaccharides are joined by dehydration synthesis, such as sucrose and maltose.

Polysaccharide

A complex carbohydrate made of many monosaccharides joined by dehydration synthesis, such as glycogen, starch, and cellulose.

Lipids

Mainly hydrophobic organic molecules composed mostly of carbon and hydrogen in a $1:2$ ratio, including fatty acids, glycerides, steroids, and phospholipids.

Saturated Fatty Acid

A fatty acid chain containing no double bonds between carbon atoms, fully saturated with hydrogen.

Unsaturated Fatty Acid

A fatty acid chain containing one or more double bonds between carbon atoms.

Triglycerides

Glycerides containing three fatty-acid tails attached to a glycerol molecule, functioning in energy storage, insulation, and protection.

Steroids

Lipids characterized by a carbon skeleton consisting of four rings, including cholesterol and hormones like estrogen, progesterone, and testosterone.

Phospholipids

Amphipathic structural lipids consisting of diglycerides bound to a phosphate group and non-lipid group, forming plasma membranes.

Proteins

Abundant organic molecules composed of carbon, hydrogen, oxygen, and nitrogen, constructed from $20$ different amino acids.

Peptide Bond

A covalent chemical bond formed between amino acids through dehydration synthesis.

Nucleic Acids

Organic molecules found in the nucleus (such as DNA and RNA) that store and process genetic information.

Nucleotide

The structural unit of nucleic acids, consisting of a pentose sugar, a phosphate group, and a nitrogenous base.

Purines

Double-ring nitrogenous bases consisting of Adenine ($A$) and Guanine ($G$).

Pyrimidines

Single-ring nitrogenous bases consisting of Cytosine ($C$), Thymine ($T$ in DNA), and Uracil ($U$ in RNA).