Some high-yield MCAT topics that are particularly vexing

Arjan Singh Puniani
4 min readAug 29, 2019


Note: it’s best to start with an understanding of how to attack MCAT passages before worrying about content. If you got an “A” or “B” in your premed courses, you are ready for timed practice. Once you’re finishing on time, then you can worry about the content needed to crack 130 on the science subsections.

I realize the general consensus is that there is no such thing as “low-yield” on the MCAT. It’s true in many ways because you’re just not sure what mix of topics will show up on your exam. Preparing for CARS (analyzing difficult passages in a timely manner) is probably the most efficient path to a higher score because critical thinking is essential to every section of the MCAT. The AAMC is fair because helpful and useful information is available in the passage. Have you noticed how passages are “adapted from” sources, like below:

Take a look at the text between the table and Question 11.

Passages are lifted from cutting-edge research journals, but at the end of the day, AAMC authors will integrate critical information into the text that makes the correct answer inevitable and defensible.

If you’re able to write a pithy explanation for the following topics, I believe you are in pretty good shape for achieving a 515+ on the real deal.

Examples given for the first three concepts of what is a good level of understanding

Marcia’s ego identity: diffusion, foreclosure, moratorium, achievement

high commitment after thoroughly vetting (high exploration) → identity achieved!

Saliva’s enzymes, including how another name for alpha amylase is PTYALIN

The mouth is for Fragmentation (masticating = chewing), Lubrication (moisten up the food bolus for passage down the alimentary canal), and some DIGESTION

  • Ptyalin = salivary amylase = catalyzes starch → disaccharides
  • Lingual lipase = some basic fat digestion
  • lysozyme = example of nonspecific immune defense for bacterial wall breakdown


We know that many biological reactions involve electron transfer (redox reactions) that result from a simultaneous reduction and oxidation half-reaction. We can relate the reaction’s spontaneity with the electromotive force at STANDARD CONDITIONS via:

∆G˚= -nFE˚

but for NONSTANDARD conditions, we need

E = E˚ — (0.06/n)logQ

  1. Mixed methods in research (qualitative v. quantitative)
  2. how do positive and negative emotions lateralize in the brain?
  3. 3 emotion components: cognitive, behavioral, physiological
  4. How does glomerular filtration rate (GFR) change with vasoconstriction and vasodilation?
  5. PBr3 v. PCl3
  6. methylating histones / DNA, acetylating histones
  7. carbinolamine
  8. gas chromatography
  9. saturation and vapor pressure; colligative properties
  10. Neural plasticity v. neural pruning
  11. Diamagnetic (all duos) v. Paramagnetic (unPaired)
  12. Order of electron removal from orbitals
  13. HMG-CoA?
  14. ∆G v. Keq v. ∆G˚ v. k = Aexp{-Ea/RT}
  15. diabetic ketoacidosis
  16. hydrophobic interaction column
  17. linoleic (omega 6) v. Linolenic acid (omega 3)
  18. Token economy (Skinner) v. 2˚ reinforcement (not food, sex, or water)
  19. Degrees of unsaturation formula and heuristic
  20. Language theories (nativist v. interactionist)
  21. Genetic linkage / recombination
  22. Penetrance / expressivity (know incomplete and variable prefixes)
  23. George H. Mead (me v. I; play v. pretend, etc.)
  24. Kinetic v. thermodynamic product
  25. Intermolecular ring closure reactions (look out for electrophile)
  26. ppm = y/100 = x/1,000,000
  27. Exonuclease v. endonuclease DNA repair mechanisms
  28. Glial cells (astrocyte, ependymal, oligodendrocytes)
  29. Robertsonian translocation
  30. Saturation, solubility, Ksp
  31. Diffraction grating
  32. Circularly polarized photons
  33. Optical power and corrective lenses
  34. Hyperopia v. myopia
  35. AMU v. g/mol
  36. Lipid transport, carnitine shuttle
  37. Sphingosine
  38. emf v. terminal voltage
  39. charging a battery and what that does to the anode and cathode
  40. homologues (sequences in DNA, structures in species)
  41. fatty acid synthesis (cytosol) and metabolism (mitochondria) and what malonoyl is
  42. cholesterol synthesis
  43. DIFFRACTION GRATING (you never know if you’re gonna get it)
  44. Buoyancy / Archimedes
  45. Amphipathic v. Amphoteric
  46. Rods, cones: which ones are hyperpolarized?
  47. Where do steroid hormones bind in the cell?
  48. What is social learning
  49. Acculturation?
  50. monocular cues
  51. Racialization v. intersectionality
  52. Self-fulfilling prophecy
  53. Imine v. enamine (definitely know the synthesis routes)
  54. social v. ego v. racial identity
  55. Marcia’s ego identity: diffusion, foreclosure, moratorium, achievement
  56. Correlational coefficient: predictor v. response variable
  57. Kuznets curve
  58. Single or double crossover event
  59. Glucocorticoid v. mineralocorticoid
  60. Between-subjects v. within-subjects
  61. most common psychological disorders? (schizo = 1% but not number 1)
  62. Sick role v. illness experience
  63. social cognitive theory v. cognitive-behavioral

I will be adding hyperlinks that branch to the topics periodically.