MCAT Study Guide: Chapter 4

Memory questions on the MCAT are exactly what they sound like: They test your knowledge about a specific fact or concept. While memory questions are typically found as free-standing questions, they can also be tucked into a passage and represent 25% of science questions on the MCAT.

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But don’t worry! Aside from requiring memorization, these questions do not generally cause problems for students because they are similar to the types of questions that would appear on a typical college science exam.

What Should I Memorize?

Mastery of the basics and the ability to apply those concepts to unfamiliar situations is what will sustain you on the MCAT. But if you’re stressing about what MCAT formulas to memorize, here is a short list of rules and equations collected by our MCAT test experts. This is by no means a definitive list but rather a sampling to jump start your prep.

And remember, it's more about application of knowledge, than straight up memorization of knowledge.

Chemistry Physics/Math

Organic Chemistry

  • recognizing and naming of organic functional groups using IUPAC nomenclature
  • CIP rules for assigning absolute configuration (R/S)
  • separation techniques, notably chromatography
  • principles of spectroscopy techniques, notably IR and 1 H-NMR
  • recognizing common organic reaction types (S N 1/S N 2, addition reactions, nucleophilic addition-elimination reactions)
  • structure, classification, and p K a s of amino acid side chains
  • structure/reactivity of carbohydrates, lipids, nucleic acids

General Chemistry

  • Avogadro's number
  • common polyatomic ions
  • Electronegativity order: FONCIBrISCH
  • masses/charges of radioactive decay particles
  • Gibbs free energy equation-ideal gas law
  • ideal gas law
  • 1 mol of a gas = 22.4 L at STP
  • phase solubility rules
  • salt solubility rules
  • common strong acids and bases
  • ion-product constant of water ( K w )
  • K a K b , p K a /p K b relationships
  • definition of pH and general logarithm math
  • Henderson-Hasselbalch equation for the pH of a buffer
  • oxidation state rules
  • loss of electrons is oxidation (LEO)
  • gain of electrons is reduction (GER)

Some handy math formulas:

  • prefixes for powers of ten
  • sine and cosine values for special angles
  • vector addition and subtraction
  • log rules
  • approximation techniques for square roots

Read more  MCAT math tips

Some constants include:

  • acceleration of gravity on Earth
  • density of water
  • Coulomb's constant
  • elementary charge
  • speed of sound in air
  • speed of light in vacuum

Some equations and the rules for using them:

  • basic kinematic equations
  • Newton's laws
  • work formula
  • conservation of energy
  • First Law of Thermodynamics
  • buoyant force equation
  • continuity equation
  • electric force-field relation
  • electric potential energy-potential relation
  • Ohm's law
  • period-frequency relation
  • wave equation
  • Doppler shift
  • Snell's law
  • mirror and lens equation

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Psychology/Sociology Biology and Biochemistry
  • characteristics of a true experiment
  • differences between independent and dependent variables
  • Weber's Law
  • difference between top-down and bottom-up processing
  • Piaget's stages of cognitive development
  • Kohlberg's stages of moral development
  • stages of sleep and characteristics of each
  • basic flow of memory encoding and retrieval
  • difference between Broca's area and Wernicke's area
  • major theories of emotion
  • major functions of each brain region
  • major personality theories
  • major psychological disorders
  • how attitude and behavior impact each other
  • major social psychology theories
  • major types of learning
  • differences between primary vs. secondary and positive vs. negative reinforcers and punishers
  • the various reinforcement schedules and behavior associated with each
  • types of attributions
  • types of negative social interactions (discrimination, bias, etc.)
  • major theoretical approaches to sociology
  • types of social institutions
  • amino acid side chain classifications (polar, non-polar, acidic, basic), their structure, and their charge at pH 7.4
  • amino acid 3-letter and 1-letter abbreviations

  • the significance of △G structures/monomers of the four biological macromolecules
  • how to recognize oxidation and reduction reactions
  • fundamentals of acid/base chemistry
  • four types of enzyme inhibitors V max and K m

  • location/regulation of biochem pathways (and when one pathway might be favored over another)

  • lab techniques (ELISA, electrophoresis, blotting, and PCR)

  • Central Dogma of molecular biology

  • DNA replication rules/enzymes

  • the start codon and the 3 stop codons

  • different types/functions of RNA

  • how transcription is regulated

  • energy required for protein translation

  • viral life cycles and genomes

  • classification of bacteria by structure/living conditions

  • role of the eukaryotic signal sequence

  • plasma membrane structure

  • passive and active transport

  • mechanism of G-protein 2nd messenger pathways

  • eukaryotic cell features (cytoskeleton, cell junctions, organelles)

  • four phases of mitosis
  • comparison of mitosis vs. meiosis
  • classical and non-classical dominance
  • 4 basic single gene crosses
  • 2 rules of probability
  • how to determine linkage and recombination frequency
  • equations and rules for Hardy-Weinberg
  • action potential and voltage-gated channels
  • CNS anatomy
  • sympathetic vs. parasympathetic
  • eye/ear anatomy
  • 5 classes of sensory receptors
  • hormones
  • heart anatomy
  • cardiac action potential
  • blood pressure, cardiac output, peripheral resistance
  • blood gas transport
  • B cell and T cell function
  • antibody structure and classes
  • nephron structure/function
  • renin-angiotensin-aldosterone system
  • digestive accessory organs
  • alimentary canal structure/function
  • sarcomere structure
  • sliding filament theory
  • muscle fiber types
  • conduction zone vs. respiratory zone
  • regulation of ventilation rate and pH
  • hormones and phases of the menstrual cycle
  • primary germ layers and what they become
  • stem cells

MCAT Tips and Tricks?

There is no specific “trick” to answering memory questions. Either you know the answer or you don’t. If you find that you are missing a fair number of memory questions on your MCAT practice tests, it is a sure sign that you don’t know the content well enough. Go back and review.

MCAT Memorization Strategies


Mnemonic devices are patterns (series of letters, the tune of your favorite song) that help you memorize. For example, some people remember the definitions of the sine, cosine, and tangent of an acute angle in a right triangle by this mnemonic: SOH CAH TOA. The letters stand for the following: Sine = Opp/Hyp, Cosine = Adj/Hyp, Tangent = Opp/Adj.

Memory Palace

This mnemonic device involves imagining that you are moving through a familiar route or place, such as the rooms of your childhood home, and at various stops along the way leaving a visual representation of a topic you want to remember. To recall the info you need, simply imagine walking through your “palace.” We’ve heard of students using this technique for everything from the steps of the Krebs cycle to the parts of the cell.


The act of writing something down goes a long way toward committing it to memory. Plus, concise and colorful one-page outlines are great study aids.

A Note About MCAT Flashcards

Flashcards can be beneficial if your basic content knowledge is deficient in some area.  However, remember that the most challenging aspect of the MCAT is not that it requires you to memorize the fine details of content knowledge, but that it requires you to apply your basic scientific knowledge to unfamiliar situations, and flashcards alone will not help you there.  If you choose to use flashcards, make sure to incorporate plenty of practice passages and full-length practice tests to round out your preparation.

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