/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 9 (a) Why is the outward transport... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 14: Problem 9

(a) Why is the outward transport of ATP favored over the outward transport of \(A D P\) by the adenine nucleotide transporter? (b) Does this ATP translocation have an energy cost to the cell?

Short Answer

Expert verified
(a) ATP transport is favored over ADP due to its greater amount of negative charges. (b) The ATP translocation does not have a direct energy cost to the cell, as it is based on the principle of charge equilibrium.

Step by step solution

01

Why ATP transport is favored

ATP transport across the membrane is favored over ADP because of its charge. ATP has more negative charges due to its three phosphate groups, making it more efficient for the adenine nucleotide transporter to carry it across the membrane.
02

Energy cost of ATP translocation

Considering the energy cost of ATP translocation to the cell, it's important to note that the translocation of ATP itself doesn鈥檛 have a strict energy cost to the cell. This is because the adenine nucleotide transporter can export one molecule of ATP while importing one molecule of ADP from the cytosol into the mitochondrial matrix, which is a process based on the principle of charge equilibrium rather than energy expenditure.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Adenine Nucleotide Transporter
The adenine nucleotide transporter is a specialized protein found in the inner mitochondrial membrane. Its primary role is to facilitate the exchange of adenine nucleotides between the mitochondrial matrix and the cytosol. This transport is essential for maintaining cellular energy balance. The transporter works by an antiport mechanism, meaning it simultaneously moves ATP and ADP in opposite directions.

ATP molecules are transported out of the mitochondria into the cytosol, where they can be used for energy-requiring processes, while ADP is brought into the mitochondria to be converted back to ATP. The transporter is highly specific, ensuring that it efficiently moves ATP and ADP across the membrane.
  • Location: Inner mitochondrial membrane
  • Function: Exchange of ATP and ADP
  • Mechanism: Antiport movement
Charge Equilibrium
Charge equilibrium is key to the ATP and ADP transport process. It refers to the balance of electric charges across the mitochondrial membrane during the exchange. Since ATP carries a more negative charge compared to ADP, its outward transport can increase the electric potential across the membrane.

This difference in electric charge is leveraged by the adenine nucleotide transporter to facilitate the transport without the direct use of energy. The transport of ATP and ADP is driven by this charge gradient. As ATP, with its negative charge, exits the mitochondria, and ADP, with a less negative charge, enters, the charge balance is maintained.
  • ATP has a more negative charge
  • Maintains electric potential balance
  • No direct energy requirement
ATP and ADP Exchange
The process of exchanging ATP and ADP between the mitochondria and the cytosol is vital for cellular energy management. ATP generated by oxidative phosphorylation in the mitochondria is transported to the cytosol for energy-dependent reactions. At the same time, ADP, a by-product of these reactions, is shuttled back into the mitochondria to be phosphorylated into ATP again.

This exchange ensures a continuous supply of ATP for cellular processes. The adenine nucleotide transporter plays a crucial role in this cycle by acting without energy input, using the natural charge equilibrium. Since ATP is more negatively charged than ADP, it naturally moves out more efficiently, supporting smooth energy turnover.
  • Provides ATP for cell energy needs
  • Recycles ADP back to mitochondria
  • Depends on charge difference

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

(a) When the widely prescribed painkiller Demerol (mepiridine) is added to a suspension of respiring mitochondria, the ratios \(\mathrm{NADH} / \mathrm{NAD} \oplus\) and \(\mathrm{Q} / \mathrm{QH}_{2}\) increase. Which electron transport complex is inhibited by Demerol? (b) When the antibiotic myxothiazole is added to respiring mitochondria, the ratios cytochrome \(c_{1}(\mathrm{Fe}) /\) cytochrome \(c_{1}\) (Fe ) and cytochrome \(b_{566}\left(\mathrm{Fe}(\mathrm{O}) /\right.\) cytochrome \(b_{\mathrm{L}}\left(\mathrm{Fe} \mathrm{O}^{\mathrm{O}}\right)\) increase. Where does myxothiazole inhibit the electron transport chain?

(a) Calculate the protonmotive force across the inner mitochondrial membrane at \(25^{\circ} \mathrm{C}\) when the electrical difference is \(-0.18 \mathrm{~V}\) (inside negative), the \(\mathrm{pH}\) outside is \(6.7\), and the \(\mathrm{pH}\) inside is 7.5. (b) What percentage of the energy is from the chemical ( \(\mathrm{pH})\) gradient, and what percentage is from the charge gradient? (c) What is the total free energy available for the phosphorylation of ADP?

In a typical marine bacterium the membrane potential across the inner membrane is \(-0.15 \mathrm{~V}\). The protonmotive force is \(-21.2 \mathrm{~kJ} \mathrm{~mol}^{-1}\). If the \(\mathrm{pH}\) in the periplasmic space is \(6.35\), what is the \(\mathrm{pH}\) in the cytoplasm if the cells are at \(25^{\circ} \mathrm{C}\) ?

Acyl CoA dehydrogenase catalyzes the oxidation of fatty acids. Electrons from the oxidation reactions are transferred to FAD and enter the electron transport chain via \(\mathrm{Q}\). The reduction potential of the fatty acid in the dehydrogenase-catalyzed reaction is about \(-0.05 \mathrm{~V}\). Calculate the free energy changes to show why FAD-not \(\mathrm{NAD}^{\oplus}\) - is the preferred oxidizing agent.

The iron atoms of six different cytochromes in the respiratory electron transport chain participate in one-electron transfer reactions and cycle between the Fe(II) and the Fe(III) states. Explain why the reduction potentials of the cytochromes are not identical but range from \(-0.10 \mathrm{~V}\) to \(0.39 \mathrm{~V}\).
See all solutions

Recommended explanations on Chemistry Textbooks

Physical Chemistry

Read Explanation

Kinetics

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Making Measurements

Read Explanation

Chemical Reactions

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.