Amino Acid Side Chains: The Twenty Personalities That Build Every Protein
A working tour of the twenty side chains, their pKa behavior, and how chemistry at the R group decides every protein fate.
9 min read
MCAT subject hub
MCAT Biochemistry Hub
Public biochemistry overview for amino acids, enzymes, metabolism, genetics, and lab technique logic.
Answer first
Biochemistry is strongest when pathways, structure, and experimental readouts are studied together. Use this page as a public overview. Full lesson flows, quizzes, and account progress stay inside the private app, while these edited guide links give crawlers and students enough context to understand the topic area before signup.
Zwitterions and Titration Curves: Charge States of Amino Acids
A working guide to amino acid charge states, the math behind isoelectric points, and how to read titration curves cold on test day.
9 min read
Peptide Bond Geometry and Resonance: Why the Backbone Is Locked Flat
How nitrogen lone-pair delocalization forces six backbone atoms into a single plane and shapes every protein fold you will see on test day.
9 min read
Why Alpha Helices and Beta Sheets Hold Together (and When They Fall Apart)
Backbone hydrogen bonding, dihedral geometry, and a few troublemaker residues decide whether a stretch of protein folds into helix, sheet, or neither.
8 min read
What Actually Holds a Folded Protein Together
A residue-by-residue look at the five forces that lock tertiary structure into shape and why the hydrophobic effect dominates them all.
9 min read
How Subunits Talk: Quaternary Structure and Allosteric Control
Quaternary structure assembles folded subunits into one functional machine, and allostery lets binding at one site reshape every other site on that machine.
8 min read
When Proteins Come Undone: Denaturation, Refolding, and the Chaperones That Help
How proteins lose their shape under heat, urea, reducing agents, and pH extremes, and how the cell sometimes coaxes them back.
9 min read
Chaperones and the Proteasome: How Cells Coach Folds and Recycle Failures
How Hsp70 and GroEL/GroES rescue half-folded chains, and how the ubiquitin-proteasome system disposes of the proteins that never make it.
8 min read