(3.7) Suppose the intracellular pH of an alkaliphile is 8.5 but the extracellular environment is atpH9.5. The cellular membrane of the bacterium has an electric potential of Af = -190 mV.How many c-subunits must the alkaliphilic ATP synthase have for it to work as an ATP synthaserather than proton pump? Assume that the free energy change for the phosphorylation of ADP toATP is AFp = +50 kJ/mol.Answer:

To determine the number of c- subunits, we need to calculate the H+/ATP ratio. H+/ATP ratio is given…

Answered: (3.7) Suppose the intracellular pH of…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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Similar questions

Explain why some of the molecules are positioned away from the diagonal in the graph given below. What kind of processes are involved in this phenomenon? Moreover, explain differences and similarities between H-ATPases and H-PPases.
Calculate the amount of ATP that be needed to be converted to ASP to pump 1mol of protons across a membrane from a solution of pH8 to pH6. (pH values are unchanged during the process). Where T=298K
A simple enzyme reaction can be described by the equation e + s ↔ es ↔ e + p, where e is the enzyme, s the substrate, p the product, and es the enzyme– substrate complex.Write a corresponding equation describing the workings of a transporter (T) that mediates the transport of a solute (s) down its concentration gradient.
Explain why the coupled reaction ATP → ADP + Pi in the P-class ion pump mechanism does not involve direct hydrolysis of the phosphoanhydride bond.
The pH values of the different compartments are shown below: matrix Intermembrane space Cytosol pH 7.8 – 8.0 pH ~ 7.0pH 7.0 – 7.4 Proton flow through ATP synthase leads to the formation of ATP, a process defined as the binding-change mechanism that was initially proposed by Boyer. Briefly explain Boyer’s binding change mechanism for the ATP synthase.
Intramitochondrial ATP concentrations are about 5 mM, and phosphate concentration is about 10 mM. If ADP is five times more abundant than AMP,calculate the molar concentrations of ADP and AMP at an energy charge of 0.85. Calculate ∆G for ATP hydrolysis at 37 °C under these conditions.The energy charge is the concentration of ATP plus half the concentration of ADP divided by the total adenine nucleotide concentration.
The standard free energy of hydrolysis of inorganic polyphosphate (polyP) is about −20 kJ/mol for each Pi released. We calculated in Worked Example 13–2 that, in a cell, it takes about 50 kJ/mol of energy to synthesize ATPfrom ADP and Pi. Is it feasible for a cell to use polyphosphate to synthesize ATP from ADP? Explain your answer.
A 75 kg person doing light work requires about 3000 kcal of food energy perday, 40% of which is actually used by the body’s cells. (The other 60% is lostas heat and in waste products.) Before being used by the cells, effectively allof this energy is stored in ATP, which is then cleaved into ADP and PO3−2 , with the release of 12.5 kcal per mole of ATP.(a) How many moles of ATP are turned over per day in this fashion? Whatmass of ATP does this correspond to? (The molecular weight of ATP is507 g/mol.)(b) The body actually contains approximately 5 g ATP. Estimate the averagerecycle time for an ATP molecule. You see that it is much more efficientto reuse ADP rather than to synthesize it de novo (from scratch).
Do you think that the EA for ATP hydrolysis is relatively low or high? Explain your reasoning.
Free energy changes under intracellular conditions differ markedly from those determined under standard conditions. ΔG°′ = -32.2 kJ/mol for ATP hydrolysis to ADP and Pi. Calculate ΔG for ATP hydrolysis in a cell at 37 °C that contains [ATP] = 3 mM, [ADP] = 1 mM, and 3Pi4 = 1 mM.
You know that the free energy of ATP hydrolysis depends on the ATP/ADP ratio. Given that under standard conditions DGo = -30.5 kJ/mol, what should be DG of ATP hydrolysis under normal intracellular concentrations? [ATP] = 2.3 mM, [ADP] = 0.25 mM, [Pi] = 1.65 mM What is the energy of ATP hydrolysis in a cell that is ATP-depleted? [ATP] = 0.1 mM, [ADP] = 2.8 mM, [Pi] = 1.65 mM
Suppose the concentration of glucose inside a cell is 0.1 mM and the cell issuspended in a glucose solution of 0.01 mM.(a) What would be the free energy change, in kJ/mol, for the transport ofglucose from the medium into the cell? Assume T = 37 °C.(b) What would be the free energy change, in kJ/mol, for the transport ofglucose from the medium into the cell if the intracellular and extracellularconcentrations were 1 mM and 10 mM, respectively?(c) If the processes described in parts (a) and (b) were coupled toATP hydrolysis, how many moles of ATP would have to be hydrolysed,per mole of glucose transported, in order to make each process favorable? (Use the standard free energy change for ATP hydrolysis.)

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