Question

What captures the energy from NA+ diffusion to move glucose against the concentration gradient?

Answer 1

The energy from Na+ diffusion is harnessed via secondary active transport, specifically through the action of Na+/glucose symport proteins and the Na+/K+ ATPase pump which requires ATP hydrolysis.

Step-by-step explanation:

The energy required for moving glucose against its concentration gradient is captured through a process known as secondary active transport. This form of transport relies on the energy from the diffusion of Na+ ions. Specifically, a Na+/glucose symport protein is responsible for this process.

As Na+ ions move down their electrochemical gradient, into the cell, they carry glucose molecules with them into the cell against the glucose concentration gradient. The Na+ ions' movement is facilitated by a Na+/K+ ATPase pump which actively expels Na+ out of the cell and maintains a low Na+ concentration inside the cell. This gradient serves as the potential energy source that drives the glucose transport.

The Na+/K+ ATPase pump requires the hydrolysis of ATP in order to function, which is why this process falls under the category of active transport. While glucose itself does not directly require ATP to be transported into the cell, the process it relies on is indirectly fueled by ATP through the maintenance of the Na+ gradient.

Answer 2

Secondary active transport captures energy from Na+ diffusion to move glucose against the concentration gradient, utilizing the Na+/glucose symport protein and the Na+/K+ ATPase pump which hydrolyzes ATP for energy.

Step-by-step explanation:

The energy used to move glucose against its concentration gradient is captured by a process called secondary active transport. This is carried out by the Na+/glucose symport protein, which uses the energy from the diffusion of Na+ down its electrochemical gradient to move glucose into the cell. The Na+/K+ ATPase pump is vital in maintaining a low concentration of Na+ inside the cell by pumping Na+ out in exchange for K+, using ATP as an energy source.

During digestion, Na+ and glucose bind to a symport carrier protein in the intestinal wall, which allows glucose to enter the cell along with Na+ moving down its concentration gradient. Subsequently, glucose diffuses into the blood. In the kidneys, a similar mechanism occurs where glucose reabsorption takes place via secondary active transport, using a Na+/glucose symport protein on the luminal surface of the renal tubules.

Maintenance of the concentration and electrochemical gradients necessary for this transport method relies on the active transport mechanism of the Na+/K+ ATPase pump. To move substances against a concentration or electrochemical gradient, active transport requires free energy from the breakdown of ATP. This process emphasizes the importance of metabolic processes in supporting active transport and the constant regulation of ion concentrations within cells.