You make a mutation in the Na+/K+ pump such that it now transports 3 K+ ions into the cell instead of two. What will be the consequence of this mutation?

Question

You make a mutation in the Na+/K+ pump such that it now transports 3 K+ ions into the cell instead of two.  What will be the consequence of this mutation?

BlackTom AI · Accepted Answer

First, consider the role of the Na+/K+ pump: it uses ATP to move ions against their gradients, typically exporting 3 Na+ ions and importing 2 K+ ions each cycle, which contributes to maintaining membrane potential and ionic gradients.
Option 1: 'ATP is no longer needed for transport' would be incorrect because the pump remains an ATP-dependent transporter; mutating the stoichiometry to move more K+ in does not remove the need for ATP hydrolysis for active transport.
Option 2: 'The pump is no longer an active transport protein' is inaccurate since the pump would still be consuming energy to move ions against their gradients, albeit with altered stoichiometry; the mechanism would still be active transport, not passive.
Option 3: 'There will be more K+ outside of the cell than inside the cell.' With the described mutation, the pump would relocate 3 K+ ions into the cell per cycle instead of 2; assuming the Na+ export aspect remains, this would actually increase intracellular K+ relative to outside, not the opposite. Therefore this statement mischaracterizes the directional outcome of the mutation.
Option 4: 'It will not generate any membrane potential' This aligns with the idea that the normal pump is electrogenic because 3 Na+ out and 2 K+ in produce a net outward positive current. If the pump now moves 3 K+ in for each cycle while possibly still exporting Na+, the net charge movement per cycle would be closer to neutral (e.g., 3 positive charges in versus 3 or 0 out, depending on exact coupling). In many plausible interpretations of the described mutation, the electrochemical current contributed by the pump would be substantially reduced or eliminated, leading to little or no direct membrane potential generation by the pump itself. Consequently, this option correctly captures the anticipated loss of the pump’s electrogenic contribution.

Thus, evaluating each choice: the first and second misstate the dependence on ATP and the activity of the pump; the third reverses the expected intracellular/extracellular distribution of potassium; the fourth accurately reflects the loss of net current generation by the altered stoichiometry, given the usual electrogenic nature of the pump. Hyperfocus on the mutation’s effect shows a shift toward neutrality of charge movement per cycle, meaning the pump would not contribute to membrane potential in the same way as the wild-type.

Bio 93 Section CDE 2025 Midterm 1- Section E

You make a mutation in the Na+/K+ pump such that it now transports 3 K+ ions into the cell instead of two. What will be the consequence of this mutation?

View Explanation

Log in for full answers

Similar Questions

For a neuron with an initial membrane potential at -70 mV, what would be the result of an increase in the movement of potassium ions out of that neuron's cytoplasm?

Refer to the following graph of an action potential to answer the question. Which Roman numeral in the graph indicates when the neuronal membrane is at its resting potential?

An increase in extracellular K+ concentration can lead to depolarization of the plasma membrane

The inside of a cell is generally more positively charged compared to the outside

The electrochemical gradient across a cell membrane typically favors the influx of sodium ions into the cell

A change in the axon membrane potential from -70 mV to -90 mV would be termed a(n) _____

The difference in electrical charge between the inside and the outside of the axon membrane is defined as the _______ potential.

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler