1 - STRUCTURES AND FUNCTIONS IN LIVING ORGANISMS 

Active transport 

• The movement of particles against the concentration gradient (from an area of lower concentration to an area of higher concentration) using energy released during respiration

eg: 

1. Higher concentration of nutrients in blood, lower concentration in gut 
2. Active transport - against diffusion/osmosis - against concentration gradient
3. Allows nutrients to be taken into blood 
4. Needs energy from respiration 

Things that affect movement of substances - 

1. Surface to area volume ratio -(larger surface area to smaller volume ratio = substances move in/out faster) 
2. Temperature -(warmer = more energy, move faster substances move in/out faster) 
3. Concentration gradient -(big difference in concentration = substance move faster) - doesn't affect active transport