Active Transport
Active transport is when molecules move through other substances with the added help of energy use. This is used when molecules cannot naturally cross a surface due to various reasons. These reasons may include:
There are several types of active transport which occurs biologically within organisms. These include:
- The molecules have fatty sections attached to them.
- Their electric charge prevents them moving across the membrane.
- They are too large to cross a membrane.
- They cannot dissolve or be dissolved within or outside of the membrane.
There are several types of active transport which occurs biologically within organisms. These include:
- The use of carrier proteins binding to molecules and carrying them through.
- Using large proteins or enzymes to alter the molecule so that it may pass through
- Endocytosis where a 'bubble' of the membrane is formed around a large molecule and the cell then 'eats' the bubble. When the bubble is inside the cell, the membrane creating it dissolves and the molecule is left in the middle of the cell.
Active Transport Within the Kidney
Within the kidney nephron system, there are many areas where active transport is used to exchange substances between the tubules and the capillaries surrounding the nephron.
Generally, all reabsorbtion and secretion activity that occurs within the kidney is due to active transport.
Active transport is used within reabsorbtion to bring back all good and necessary nutrients into the blood stream if they had previously diffused passively into the tubular network. Reabsorbtion materials include: glucose, amino acids, vitamins, minerals, bicarbonate ions and some water. This reabsortion occurs within the proximal and distal convoluted tubules and within the loop of Henle.
Scecretion uses active transport to deliberately place some salts and urea into the proximal and distal convoluted tubules.
Generally, all reabsorbtion and secretion activity that occurs within the kidney is due to active transport.
Active transport is used within reabsorbtion to bring back all good and necessary nutrients into the blood stream if they had previously diffused passively into the tubular network. Reabsorbtion materials include: glucose, amino acids, vitamins, minerals, bicarbonate ions and some water. This reabsortion occurs within the proximal and distal convoluted tubules and within the loop of Henle.
Scecretion uses active transport to deliberately place some salts and urea into the proximal and distal convoluted tubules.