IB Biology B2.1 Definitions
This page contains our IB Biology definitions for B2.1. By learning each one of these definitions, you will fully cover the content for IB Biology 'Membranes and transport'.
active transport
The movement of substances across membranes usually against concentration gradients, requiring energy from ATP
amphipathic
A molecule's property of being both hydrophobic and hydrophilic
diffusion
The net passive movement of particles from areas of high concentration to areas of low concentration, requiring no energy
faciliated diffusion
The passive movement of particles from areas of high concentration to areas of low concentration via specific channel proteins
hydrophilic
Attracted to water (water-loving)
hydrophobic
Repelled to water (water-fearing)
osmosis
The movement of water from a region of low solute concentration to a region of high solute concentration, across a partially permeable cell membrane
peripheral protein
A protein on the surface of the plasma membrane
simple diffusion
The passive movement of particles from areas of high concentration to areas of low concentration across a semi-permeable membrane
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