Transport Across Membrane — Prelims Strategy

Prelims Strategy

To excel in NEET questions on transport across the membrane, a systematic approach is vital. First, clearly differentiate between passive and active transport based on energy requirement and movement relative to the concentration gradient.

For passive transport, understand simple diffusion (small, nonpolar, lipid-soluble), facilitated diffusion (protein-mediated, saturable, specific, for larger/charged molecules), and osmosis (water movement).

Memorize key examples for each. For active transport, distinguish between primary (direct ATP use, e.g., Na$^+$/K$^+$ pump) and secondary (uses existing gradient, e.g., Na$^+$-glucose symporter). Pay close attention to bulk transport (endocytosis, exocytosis) and its subtypes.

For numerical or application-based questions, especially on osmosis, understand terms like isotonic, hypotonic, and hypertonic solutions and their effects on both plant and animal cells. Practice identifying the type of transport from a given description or diagram.

Trap options often involve mixing characteristics of different transport types (e.g., saying facilitated diffusion requires ATP). Always re-read the question carefully to identify keywords like 'against gradient,' 'requires ATP,' 'saturable,' or 'large particles.