Active Transport

• Active transport is the movement of molecules against their concentration gradient from an area of lower concentration to an area of higher concentration, requiring energy from the cell.
• Active transport always takes place across a membrane, such as the cell membrane, and requires special proteins that sit in the membrane and transfer the molecule from one side to the other.
• Like all energy in the cell, the energy for active transport comes from solar respiration, which is the process that happens mainly in the mitochondria when they break down glucose to release energy.
• Solar respiration is responsible for all of the energy that the cell uses and stores the energy in literal molecules called ATP.
• ATP molecules act like little batteries, taking the energy from the mitochondria to the different parts of the cell that need it.
• Plants need to absorb large amounts of water and mineral ions to survive, which they obtain from the soil.
• Plants have networks of roots that protrude into the ground, and around the outside of these roots are special cells called root hair cells which absorb the water and mineral ions and are adapted to their role by having long hair-like protrusions where they stick out into the soil, providing a large surface area for absorption.
• The minerals and nutrients that plants need like magnesium and nitrates are at a higher concentration inside the cell than they are outside in the soil, and they cannot absorb them by diffusion, instead they have to use energy to absorb them by active transport against their concentration gradient, with the energy coming from cellular respiration which happens in mitochondria.
• An adaptation of root hair cells is having lots and lots of mitochondria.