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B1 L) Active Transport
B1 L) Active Transport
Substances can move through membranes in 3 different ways; diffusion, osmosis and active transport. We are going to look at active transport in this section.
Active transport is the net movement of particles against a concentration gradient (from an area of low concentration to an area of high concentration)
Active transport is the opposite of diffusion. Energy is required for active transport to take place; the energy is obtained by respiration reactions (glucose + oxygen –> carbon dioxide + water [+ energy]). The diagram below shows active transport.
On the above diagram, the right side has a higher concentration than the left side. This means that the net movement of particles for active transport will be from left (low concentration) to right (high concentration). Energy is required for active transport to take place and this energy is obtained from respiration reactions.
Here are some examples of where active transport takes place.
Here are some examples of where active transport takes place.
Root Hair Cells
Root hair cells are found on the surface of roots in plants. Root hair cells use active transport to bring in as much nutrients and mineral ions as possible for the plant. The root hair cells do this to ensure that the plant has enough nutrients and mineral ions for healthy growth. A diagram of a root hair cell is shown below.
Root hair cells are found on the surface of roots in plants. Root hair cells use active transport to bring in as much nutrients and mineral ions as possible for the plant. The root hair cells do this to ensure that the plant has enough nutrients and mineral ions for healthy growth. A diagram of a root hair cell is shown below.
The concentration of mineral ions is higher inside the root hair cell than in the soil. This would mean that if the mineral ions followed the rule of diffusion, the mineral ions would move from inside the root hair cell (high concentration) to the soil (low concentration).
However, the plant will want to have as many mineral ions as possible to ensure healthy growth, and it does this by engaging in active transport. Active transport allows the root hair cells to move particles against a concentration gradient (from low to high), which means that the root hair cells can continue to bring in mineral ions from the soil (low concentration) to inside the root hair cells (high concentration). Energy is required in order for active transport to take place, and the energy is obtained from respiration reactions.
Root hair cells have a very large surface area to facilitate the efficient exchange of substances.
Plants – Waterlogged Conditions
Active transport requires energy, which is obtained from respiration reactions; the equation for respiration is: glucose + oxygen –> carbon dioxide + water [+ energy]. The oxygen needed for the respiration reactions in root hair cells comes from the soil and there is usually plenty of oxygen in soil. However, waterlogged soil contains little or no oxygen. This means that the root hair cells will be unable to undertake respiration reactions due to the lack of oxygen; no respiration reactions means that no energy is produced. As no energy is produced, the root hair cells will be unable to undertake active transport and therefore may not be able to take in sufficient quantities of mineral ions and nutrients that the plant needs for health growth. This can affect the development of the plant (it may have stunted growth) and may result in the plant dying.
However, the plant will want to have as many mineral ions as possible to ensure healthy growth, and it does this by engaging in active transport. Active transport allows the root hair cells to move particles against a concentration gradient (from low to high), which means that the root hair cells can continue to bring in mineral ions from the soil (low concentration) to inside the root hair cells (high concentration). Energy is required in order for active transport to take place, and the energy is obtained from respiration reactions.
Root hair cells have a very large surface area to facilitate the efficient exchange of substances.
Plants – Waterlogged Conditions
Active transport requires energy, which is obtained from respiration reactions; the equation for respiration is: glucose + oxygen –> carbon dioxide + water [+ energy]. The oxygen needed for the respiration reactions in root hair cells comes from the soil and there is usually plenty of oxygen in soil. However, waterlogged soil contains little or no oxygen. This means that the root hair cells will be unable to undertake respiration reactions due to the lack of oxygen; no respiration reactions means that no energy is produced. As no energy is produced, the root hair cells will be unable to undertake active transport and therefore may not be able to take in sufficient quantities of mineral ions and nutrients that the plant needs for health growth. This can affect the development of the plant (it may have stunted growth) and may result in the plant dying.
Humans – Inside the Gut
Active transport happens in the gut to ensure that we absorb as much nutrients as possible into the bloodstream. The nutrients absorbed is glucose, amino acids, minerals etc.
When there is a higher concentration of nutrients in the gut and a lower concentration of nutrients in the bloodstream, the net movement of nutrients by diffusion would be from the gut (high concentration) into the bloodstream (low concentration). This would happen just after we have eaten.
However, sometimes the concentrations would be the other way around, and there will be a lower concentration of nutrients in the gut and a higher concentration of nutrients in the bloodstream. If left to diffusion, the net movement of nutrients would be from the bloodstream (high concentration) to the gut (low concentration). This would not be beneficial as it would mean that nutrients is leaving the body by entering the gut, passing through the intestines and then being excreted out. Active transport ensures that this does not happen, and means that nutrients is still taken into the bloodstream despite there being a lower concentration in the gut and a higher concentration in the bloodstream.
Active transport happens in the gut to ensure that we absorb as much nutrients as possible into the bloodstream. The nutrients absorbed is glucose, amino acids, minerals etc.
When there is a higher concentration of nutrients in the gut and a lower concentration of nutrients in the bloodstream, the net movement of nutrients by diffusion would be from the gut (high concentration) into the bloodstream (low concentration). This would happen just after we have eaten.
However, sometimes the concentrations would be the other way around, and there will be a lower concentration of nutrients in the gut and a higher concentration of nutrients in the bloodstream. If left to diffusion, the net movement of nutrients would be from the bloodstream (high concentration) to the gut (low concentration). This would not be beneficial as it would mean that nutrients is leaving the body by entering the gut, passing through the intestines and then being excreted out. Active transport ensures that this does not happen, and means that nutrients is still taken into the bloodstream despite there being a lower concentration in the gut and a higher concentration in the bloodstream.