Cells and membranes
Membrane structure, transport logic, organelles, and how structure drives function.
Cells are organized, not random. The cell membrane is the control surface that keeps the inside stable while still allowing exchange with the outside. Every gradient across a membrane stores potential work. Every membrane protein decides whether that potential is used, conserved, or lost. The MCAT favors membrane topics because they let a passage blend chemistry, physics, and physiology: diffusion, charge, and downstream consequences. If you can narrate what moves, why it moves, and what happens when a barrier changes, you can solve most membrane-based passages even when the context feels unfamiliar.
- Membranes stabilize gradients and control traffic
- Channels are fast pores; carriers are selective transporters
- Active transport uses energy to move against gradients
- Osmosis follows solute concentration and affects cell volume
- Membrane changes propagate to system-level effects
Describe one system (nervous, muscular, renal) that depends on membrane gradients and explain what fails if those gradients collapse.
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Step-by-step math problem solving.
Open textbook chapters for cell structure and transport.
Video lessons and practice (link only).
Official MCAT overview from AAMC (link-only).
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