Question

now combine the two parts together.

1. atp + proton pump
2. adp + proton pump p
3. adp + proton pump + p

for each of the two steps in the reaction, is the δg positive or negative and why?
indicate the free energy states of the reaction components at different points with bar graphs.
free energy
lots
some
a little
transporter + atp + h⁺ inside
transporter - p + adp + h⁺ inside
transporter + adp + pi + h⁺ outside

Explanation:

Step1: Analyze first - step reaction

The first - step reaction is ATP + proton pump. ATP hydrolysis is an exergonic reaction. Exergonic reactions have a negative $\Delta G$ because they release free energy. Here, ATP is hydrolyzed to ADP and inorganic phosphate (Pi) when interacting with the proton pump. So, for the reaction of ATP + proton pump $
ightarrow$ ADP+ proton - pump - P, $\Delta G<0$.

Step2: Analyze second - step reaction

The second - step reaction involves the movement of protons across the membrane using the energy released from the phosphorylation of the proton pump. This is an active - transport process driven by the energy from the previous ATP - hydrolysis step. Since it is part of an overall energy - coupling process where the initial energy release (from ATP hydrolysis) is used to drive this process, and it is a non - spontaneous process on its own that is made spontaneous by the coupled reaction, the overall $\Delta G$ for the second step (including the energy input from the first step) is also negative.

For the bar - graph:

• The "Transporter + ATP + H⁺ inside" state has the highest free energy as it contains ATP which is a high - energy molecule.
• The "Transporter - P+ADP + H⁺ inside" state has lower free energy than the previous state because ATP has been hydrolyzed to ADP and the transporter is phosphorylated.
• The "Transporter + ADP + Pi + H⁺ outside" state has the lowest free energy as the energy from ATP hydrolysis has been used to pump protons outside the cell, and the phosphate group has been released.

Answer:

For the first step (ATP + proton pump $
ightarrow$ ADP + proton - pump - P), $\Delta G$ is negative because ATP hydrolysis is an exergonic reaction. For the second step (using the phosphorylated proton pump to transport protons), $\Delta G$ is negative as it is an energy - coupled process driven by the exergonic ATP - hydrolysis step. The bar - graph would show the free energy decreasing from "Transporter + ATP + H⁺ inside" to "Transporter - P+ADP + H⁺ inside" and then to "Transporter + ADP + Pi + H⁺ outside".