ACTIVE TRANSPORT

Active Transport

● Some ions are more concentrated on one side of a cell than the other

● They are being moved across the membrane against their diffusion gradient

● This is active transport● It requires energy from respiration

This bar chart shows the differences in concentrations of ions in a freshwater plant’s cells and in the water around the plant

If the ions moved in/out by diffusion they would eventually have the same concentration both inside and outside the cellsThese ions are in higher concentrations inside so we know they are taken up by active transport, against the diffusion gradient

This requires energy from respiration.If respiration is blocked then active transport stops and only diffusion occurs

● Active transport requires a protein in the membrane

that the ion binds to● The protein changes shape when energy is

supplied● The ion is moved to the other side of the

membrane

Active transport is used to:

● Take ions into root hair cells

Use the information coming up to complete your notes…

In this diagram there are more magnesium ions inside the root hair cell than there are in the soil waterIf these ions moved by diffusion they would move out of the root hair cellAfter a while there would be the same amount of magnesium inside and outside the root hair cell

Because there are so many more magnesium ions in the cell we can assume they are being actively moved against their concentration gradient by Active Transport using Energy from Respiration

There are carrier proteins in the membrane of the root hair cell

● Absorb digested nutrients in ileum

Glucose is taken up from the gut into the blood by active transportThe epithelial cells lining the villi have a high rate of respiration and carrier proteins

● Reabsorption of glucose in kidney

The kidneys remove excess water and salts and urea

Water and solutes are squeezed out of the bloodGlucose is reabsorbed using active transport