active transport

• the concentration of minerals is usually higher in the root hair cells than in the soil around them
• so the root hair cells can't use diffusion to take up minerals from the soil
• they use active transport instead
• active transport allows the plant to absorb minerals from a very dilute solution in the soil- its moves the minerals against the concentration gradient
• but active transport needs energy from respiration to make it work
• the body needs to absorb nutrients ( eg glucose and amino acids ) from food to survive
• the nutrients have to move from the gut into the blood
• where there's higher concentration of nutrients in the gut, they diffuse into the blood
• sometimes there's a lower concentration of nutrients in the gut than there is in the blood
• the body uses active transport to move the nutrients ( like glucose ) from a lower concentration to the gut to a higher concentration in the blood
• this means glucose can be taken into the blood against the concentration gradient. the glucose is then transport to cells, where it used for respiration