Question

What combination of the following reactions is an example of energetic coupling in a cell? Equation 1: ATP+H₂O → ADP + P, AG₁=-7 kcal/mol Equation 2: phosphoenolpyruvate + H₂O → pyruvate +P, AG, = -14.8 Kcal/mol Equation 3: glucose +P→glucose-6-phosphate +H₂O AG, = +3.3 kcal/mol Equation 4: ADP+ P, ATP + H₂O AG₁=+7 kcal/mol

Answer 1

The combination of reactions that is an example of energetic coupling in a cell involves ATP hydrolysis and ATP synthesis. The energy released from the hydrolysis of ATP is used to drive the synthesis of ATP, allowing it to continue cycle. This energy coupling plays a crucial role in cellular work and is exemplified by the sodium-potassium pump.

Step-by-step explanation:

The combination of reactions that is an example of energetic coupling in a cell is:

Equation 1: ATP + H₂O → ADP + P, ΔG₁ = -7 kcal/mol

Equation 4: ADP + P → ATP + H₂O, ΔG₁ = +7 kcal/mol

In this example, the exergonic reaction of ATP hydrolysis (Equation 1) is coupled with the endergonic reaction of ATP synthesis (Equation 4), allowing them to proceed. The energy released from the hydrolysis of ATP is used to drive the synthesis of ATP, which is a highly unstable molecule and quickly dissociates into ADP and phosphate. This mechanism of energy coupling is essential for cellular work and is used in various processes, including the sodium-potassium pump.

Answer 2

The combination of ADP + P → ATP + H₂O and phosphoenolpyruvate + H₂O → pyruvate +P is an example of energetic coupling in a cell. Energy released during the hydrolysis of ATP is used to drive the conversion of phosphoenolpyruvate into pyruvate through phosphorylation.

Step-by-step explanation:

The combination of Equation 4: ADP + P → ATP + H₂O and Equation 2: phosphoenolpyruvate + H₂O → pyruvate +P is an example of energetic coupling in a cell.

During the hydrolysis of ATP (Equation 4), energy is released and the gamma phosphate group is transferred to the pump protein through phosphorylation. This energy is then used to drive the endergonic reaction of converting phosphoenolpyruvate into pyruvate (Equation 2).

Through this process of energy coupling, ATP performs cellular work by transferring energy from the exergonic reaction to the endergonic reaction, allowing both reactions to proceed.