MCAT Comprehensive Review Sheets

A comprehensive vocabulary set covering the foundational topics of the MCAT review, including General Chemistry, Organic Chemistry, Biology, Biochemistry, Physics, and Behavioral Sciences.

Heisenberg Uncertainty Principle

The principle stating that it is impossible to know the momentum and position of a particle simultaneously.

Hund’s Rule

The rule stating that electrons only double up in orbitals if all orbitals first have 1 electron.

Pauli Exclusion Principle

The principle stating that paired electrons must have opposite spins ($+\frac{1}{2}, -\frac{1}{2}$).

Diamagnetic

A state where all electrons are paired; these materials are repelled by an external magnetic field.

Paramagnetic

A state where one or more unpaired electrons are present; these materials are pulled into an external magnetic field.

Effective Nuclear Charge ($Z_{eff}$)

The net positive pull from the nucleus experienced by valence electrons.

Ionization Energy (IE)

The amount of energy required to lose or remove an electron from an atom.

Electronegativity (EN)

The force that an atom exerts on an electron within a chemical bond.

VSEPR Theory

Valence Shell Electron Pair Repulsion Theory, used to predict the molecular shape and electronic geometry based on electron groups around a central atom.

Coordinate Covalent Bond

A type of covalent bond where a single atom provides both bonding electrons, typically found in Lewis acid-base chemistry.

Metathesis

Another name for a double-displacement reaction, where elements from two different compounds swap places.

Standard Temperature and Pressure (STP)

A standard set of conditions defined as $0^{\circ}\text{C}$ (273 K) and $1\,\text{atm}$. At STP, one mole of ideal gas occupies $22.4\,\text{L}$.

Isolated System

A system that can exchange neither matter nor energy with its environment.

State Functions

Physical properties that describe an equilibrium state and are pathway independent, such as pressure, density, temperature, and enthalpy.

Hess’s Law

The principle stating that total enthalpy changes are additive ($\Delta H_{rxn}^{\circ} = \Delta H_{products}^{\circ} - \Delta H_{reactants}^{\circ}$).

Entropy ($S$)

A measure of the degree to which energy has spread throughout a system or its surroundings.

Graham’s Law

The law stating that the rate of diffusion or effusion of a gas is inversely proportional to the square root of its molar mass ($\frac{r_1}{r_2} = \sqrt{\frac{M_2}{M_1}}$).

Colligative Properties

Physical properties of solutions that depend on the concentration of dissolved particles rather than their chemical identity, including boiling point elevation and osmotic pressure.

Raoult’s Law

The law describing vapor pressure depression ($P_A = X_A P_A^{\circ}$), stating the presence of solutes decreases the evaporation rate of the solvent.

Amphoteric Species

A species that can behave as either an acid or a base depending on the environment.

Disproportionation

A redox reaction in which the same element is both oxidized and reduced, forming products with different oxidation states.

Faraday Constant ($F$)

The charge of one mole of electrons, approximately equal to $96,485\,\text{C}$ (often rounded for calculation to $96,000\,\text{C}$).

Structural Isomers

Isomers that share only a molecular formula and have different physical and chemical properties.

Enantiomers

Nonsuperimposable mirror images that have opposite stereochemistry at every chiral carbon.

Meso Compounds

Molecules with internal planes of symmetry that are optically inactive even if they contain chiral centers.

Nucleophile

A 'nucleus-loving' species containing lone pairs or pi-bonds, characterized by low electronegativity and often a negative charge.

Lytic Cycle

A bacteriophage life cycle where virions are produced until the host cell lyses.

Lysogenic Cycle

A bacteriophage life cycle where the virus integrates into the host genome as a provirus or prophage, remaining dormant until activated by stress.

Nondisjunction

The failure of sister chromatids or homologous chromosomes to separate properly during anaphase, resulting in aneuploidy.

Totipotent Stem Cells

Stem cells that have the capacity to differentiate into any cell type, including placental structures.

Glial Cells

Support cells of the nervous system, including astrocytes (blood-brain barrier), ependymal cells (CSF barrier), and microglia (waste digestion).

Red Cat / An Ox

A mnemonic for electrochemical cells: Reduction occurs at the Cathode, while Oxidation occurs at the Anode.

Bicarbonate Buffer System

The physiological buffer system described by the equilibrium: $\text{CO}_2 (g) + \text{H}_2\text{O} (l) \rightleftharpoons \text{H}_2\text{CO}_3 (aq) \rightleftharpoons \text{H}^+ (aq) + \text{HCO}_3^- (aq)$.

Opsonization

The process by which antibodies mark pathogens for destruction by other immune cells.

Acinar Cells

Cells in the pancreas that produce pancreatic juices containing bicarbonate, amylase, peptidases, and lipase.

Sarcomere

The basic contractile unit of striated muscle, composed of thick myosin and thin actin filaments.

Law of Independent Assortment

Mendel's law stating that the inheritance of one allele for a trait does not influence the probability of inheriting an allele for a different trait.

Zwitterion

A neutral molecule with both positive and negative charges, typically found in amino acids at their isoelectric point ($pI$).

Michaelis Constant ($K_m$)

The substrate concentration at which an enzyme runs at half of its maximum velocity ($V_{max}$).

Fluid Mosaic Model

The model describing the cell membrane as a dynamic, semisolid bilayer containing lipids, proteins, and carbohydrates.

Glycogenesis

The production of glycogen from glucose using enzymes like Glycogen Synthase and Branching Enzyme.

Citrate Synthase

The enzyme that couples acetyl-CoA to oxaloacetate to form citrate at the start of the Citric Acid Cycle.

Weber’s Law

The principle stating that the just noticeable difference ($JND$) for a stimulus is proportional to the magnitude of the stimulus.

Long-Term Potentiation

The result of increased neuronal connectivity and elaborate rehearsal leading to long-term memory storage.

Piaget’s Sensorimotor Stage

The stage from ages 0 to 2 involving circular reactions and the development of object permanence.

Maslow’s Hierarchy of Needs

A pyramid of motivation prioritizing needs in the order: physiological, safety, love/belonging, self-esteem, and self-actualization.

Anomie

A state of lack of social norms or the breakdown of social bonds between individuals and society.