Question
using the acid hypothesis explain how auxins bring about cell enlargement in plants
Answers
GPT 3.5
The acid hypothesis suggests that auxins increase the acidity in the cell walls of plants, which leads to cell enlargement. Here's a step-by-step explanation of how this process occurs:
1. Auxins are a class of plant hormones responsible for various growth processes, including cell elongation. They are produced in the tips of shoots and roots and then transported to other parts of the plant.
2. When auxins are transported to the plant cells, they bind to specific receptors present on the plasma membrane of the cells.
3. This binding triggers a signaling pathway that ultimately leads to the activation of specific proton pumps called H+-ATPases present in the plasma membrane.
4. The activated H+-ATPases actively pump hydrogen ions (H+) from the cytoplasm into the cell wall space.
5. As more hydrogen ions are pumped into the cell wall, the pH of the cell wall becomes more acidic. This increased acidity is primarily due to the accumulation of these hydrogen ions.
6. The acidic environment in the cell wall activates enzymes called expansins. Expansins are proteins that break the bonds between cellulose microfibrils in the cell wall.
7. By breaking these bonds, expansins loosen the cell wall structure and allow for easier expansion and elongation of the cells.
8. The increased acidity and the action of expansins contribute to the cell wall becoming more flexible and expansible, resulting in cell enlargement.
In summary, the acid hypothesis suggests that auxins stimulate the transport of hydrogen ions into the cell wall, leading to increased acidity. This acidic environment activates expansins, which loosen the cell wall structure, allowing for cell enlargement and elongation.
1. Auxins are a class of plant hormones responsible for various growth processes, including cell elongation. They are produced in the tips of shoots and roots and then transported to other parts of the plant.
2. When auxins are transported to the plant cells, they bind to specific receptors present on the plasma membrane of the cells.
3. This binding triggers a signaling pathway that ultimately leads to the activation of specific proton pumps called H+-ATPases present in the plasma membrane.
4. The activated H+-ATPases actively pump hydrogen ions (H+) from the cytoplasm into the cell wall space.
5. As more hydrogen ions are pumped into the cell wall, the pH of the cell wall becomes more acidic. This increased acidity is primarily due to the accumulation of these hydrogen ions.
6. The acidic environment in the cell wall activates enzymes called expansins. Expansins are proteins that break the bonds between cellulose microfibrils in the cell wall.
7. By breaking these bonds, expansins loosen the cell wall structure and allow for easier expansion and elongation of the cells.
8. The increased acidity and the action of expansins contribute to the cell wall becoming more flexible and expansible, resulting in cell enlargement.
In summary, the acid hypothesis suggests that auxins stimulate the transport of hydrogen ions into the cell wall, leading to increased acidity. This acidic environment activates expansins, which loosen the cell wall structure, allowing for cell enlargement and elongation.