- Active Transport
- What is it?
- We may be familiar with diffusion and osmosis, where molecules move from an area of high concentration to a low concentration. However active transport is quite the opposite. Sometime molecules need to move from a dilute solution to a higher concentrated area, but this can not be carried out by osmosis or diffusion. This is where active transport comes in and allows molecules to go against the concentration gradient move from a lower to higher concentration or through a partially permeable membrane.
- How does it work?
- Carrier proteins carry the molecule through the cell membrane. It transports the protein and rotates and releases it into the cell, then returns to its original position. This process requires energy as it is using it all the time. Active transport therefore needs lots of mitochondria which release energy through respiration. Without this active transport would not be able to happen.
- Where is it used?
- Plants- soil and roots. The soil is dilute solution, however mineral ions are needed to be transported through the plant. Active transport is therefore needed to provide the plant with mineral ions by going from a low concentration to a higher concentration.
- Active human- Digestion. Active transport is used to move substance from the small intestines to the villi. Carbohydrates are broken down into simple sugars, such as glucose and transported to the villi moving from a low concentration to a higher one. It this then passed into blood stream and travels around the body.
- What is it?