Active Transport

• The cells on plant roots grow into ‘hairs’ which stick out into the soil.
• Each branch of a root of a plant is covered in millions of microscopic ‘hairs’.
• The millions of ‘hairs‘ on plant‘s roots gives the plant a large surface area for absorbing water and mineral ions from the soil.
• Plants absorb mineral ions from the soil for healthy growth. This process is called active transport.
• When plants absorb mineral ions from the soil, 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. This is why they use active transport.
• In plants, minerals should move out of the root hairs if they followed the rules of diffusion so the cells must use another method to draw them in. This method is called active transport.
• Active transport allows a plant to absorb minerals from a very dilute solution, against a concentration gradient. This is essential for its growth. But active transport needs energy from respiration to make it work.
• Active transport happens in humans, for example in taking glucose from the gut and from the kidney tubules.
• Active transport is used in the human gut when there is a lower concentration of nutrients there but a higher concentration of nutrients in the blood.
• When there’s a higher concentration of glucose and amino acids in the human gut, they diffuse naturally into the blood, but sometimes there’s a lower concentration of nutrients in the gut than there is in the blood. This means that the conc gradient is the wrong way so active transport is used.
• Active transport allows nutrients to be taken into the blood, despite the fact that the conc gradient is the wrong way. This means that in humans, glucose can be taken into the bloodstream when its conc in the blood is already higher than the gut. It can then be transported to cells, where it’s used for respiration.