MCAT Emergency Guide

These flashcards cover key concepts, equations, and definitions for various topics including Acid-Base Chemistry, Equilibrium, Gas Laws, Thermodynamics, Electrochemistry, Enzyme Kinetics, Optics, Electricity, Work and Energy, Metabolism, and Data Analysis.

pH = pKa + log([base]/[acid])

Henderson-Hasselbalch equation

pH = pKa + 1

Buffer with ratio 10:1 (basic buffer)

pH = pKa1

Buffer with ratio 1:10 (acidic buffer)

pH = pKa

Buffer with ratio 1:1 (optimal buffer capacity)

pl = (pKa1 + pKa2)/2

Isoelectric point calculation

Ksp = [A][B]; solubility = √Ksp

Ksp expression for salt AB

Ksp = [A][B]²; [B] = 2[A]; Ksp = 4[A]³

Ksp expression for salt AB₂

Shifts reaction to the left (toward reactants)

Le Châtelier's principle - adding product

Shifts reaction to the right (toward products)

Le Châtelier's principle - removing product

Shifts reaction to the right (toward products)

Le Châtelier's principle - adding reactant

Shifts reaction toward fewer gas molecules

Le Châtelier's principle - increasing pressure

No effect on equilibrium position, only increases rate

Effect of catalyst on equilibrium

PV = nRT (R = 0.0821 L-atm/mol·K)

Ideal Gas Law

1 mol = 22.4 L

Molar volume at STP

P1V1/T1 = P2V2/T2

Combined Gas Law

P1V1 = P2V2 (constant temperature)

Boyle's Law

V₁/T₁ = V2/T2 (constant pressure)

Charles' Law

P₁/T₁ = P2/T2 (constant volume)

Gay-Lussac's Law

V × n (at constant temperature and pressure)

Avogadro's Law

AG = AH-TAS

Gibbs Free Energy equation

Negative AG

Spontaneous reaction criteria

AG° = -RT In(Keq)

Relationship between standard free energy and equilibrium constant

Keq > 1

Condition for negative AG° and spontaneous reaction

Keq < 1

Condition for positive AG° and non-spontaneous reaction

AU = q + w

First Law of Thermodynamics

Entropy of isolated systems increases over time

Second Law of Thermodynamics

Oxidation occurs here (loss of electrons)

Anode ('AN OX')

Reduction occurs here (gain of electrons)

Cathode ('RED CAT')

Spontaneous reaction, produces electricity

Galvanic cell (battery)

Non-spontaneous reaction, requires electricity input

Electrolytic cell

Higher (more positive) E° = stronger oxidizing agent

Standard reduction potential interpretation

Higher (more positive) E° = stronger reducing agent

Standard oxidation potential interpretation

E cell = E cathode - E°anode

Cell potential calculation

v = Vmax[S]/(Km + [S])

Michaelis-Menten equation

1/v = (Km/Vmax)(1/[S]) + 1/Vmax

Lineweaver-Burk equation (double reciprocal plot)

Substrate concentration at 1/2 Vmax; lower Km = higher affinity

Meaning of Km

Turnover number = Vmax/[E]total

kcat definition

Increases apparent Km, same Vmax; can be overcome with high [S]

Effect of competitive inhibitor

Decreases Vmax, same Km; cannot be overcome with high [S]

Effect of noncompetitive inhibitor

Binding of effector molecule at site other than active site

Allosteric regulation

1/f = 1/do + 1/di

Lens equation

M = -di/do = hi/ho

Magnification formula

Real, inverted, reduced image

Converging lens (object beyond 2f)

Real, inverted, same size image

Converging lens (object at 2f)

Real, inverted, enlarged image

Converging lens (object between f and 2f)

Virtual, upright, enlarged image

Converging lens (object inside f)

Always forms virtual, upright, reduced images

Diverging lens (any object position)

V = IR

Ohm's Law

P = IV = I²R = V²/R

Electrical power formulas

Rtotal = R1 + R2 + R3…

Series resistors formula

1/Rtotal = 1/R₁ + 1/R2 + 1/R3…

Parallel resistors formula

1/Ctotal = 1/C₁ + 1/C2 + 1/C3…

Capacitance in series formula

Ctotal = C₁ + C₂ + C3…

Capacitance in parallel formula

E = 1/2 CV²

Energy stored in a capacitor

W = Fd cos(θ)

Work formula

U = ½kx²

Elastic potential energy

KE = 1/2 mv²

Kinetic energy

PE = mgh

Gravitational potential energy

KEinitial + PEinitial = KEfinal + PEfinal

Conservation of energy

P = W/t = Fv

Power formula

p = mv

Momentum formula

Glucose → 2 Pyruvate + 2 ATP + 2 NADH

Glycolysis net products

Acetyl-CoA → 2 CO2 + 3 NADH + 1 FADH2 + 1 GTP

TCA (Krebs) Cycle net products

32-34 ATP (36-38 Aerobic total)

Electron Transport Chain ATP yield

Inner mitochondrial membrane

Location of oxidative phosphorylation

Breaks down fatty acids into acetyl-CoA units (2 carbons at a time)

Beta oxidation

Synthesis of glucose from non-carbohydrate precursors

Gluconeogenesis

Generates NADPH and ribose-5-phosphate

Pentose phosphate pathway function

Significance of sigmoidal curves

Cooperative processes (e.g., hemoglobin O2 binding, protein folding)

Significance of hyperbolic curves

Non-cooperative processes (e.g., myoglobin O2 binding, simple enzyme kinetics)

Significance of linear plots

Direct proportionality between variables

Significance of bell curves

Normal distribution (68-95-99.7 rule)

Exponential decay curve interpretation

First-order processes (e.g., radioactive decay, drug elimination)

Michaelis-Menten curve

Enzyme reaction rate vs. substrate concentration

Arrhenius plot

In(k) vs. 1/T gives straight line with slope = -Ea/R

X-intercept is -1/Km

Where is Km on Lineweaver-Burke Plot

Y-Intercept is 1/Vmax

Where is Vmax on Lineweaver-Burke Plot

E=hf=hc/λ

Energy of a Photon