Which of the following statements best describes the movement of ions across the plasma membrane? Multiple Choice The membrane potential is contributed to only by ions with a positive charge. Movement of K+ ions depends on the concentration of Na+ ions to either side of the membrane. Each ion species follows its own diffusion gradient, regardless of differences in the concentration of other ion species. The ion channels contributing to the membrane potential are unidirectional.
Added by Fernando S.
Step 1
" - This statement is incorrect because both positive (cations) and negative (anions) ions contribute to the membrane potential. Show more…
Show all steps
Your feedback will help us improve your experience
Joanna Quigley and 54 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Which statements are true? Explain why or why not. The membrane potential arises from movements of charge that leave ion concentrations practically unaffected, causing only a very slight discrepancy in the number of positive and negative ions on the two sides of the membrane.
Drag and drop the correct word or phrase to complete the sentences related to the resting membrane potential. The resting membrane potential is created by a small concentration of ions in the cytosol along the inside of the membrane, and an equal concentration of ions in the extracellular fluid. This separation of positive and negative electrical charges is a form of energy. The resting membrane potential arises from three major factors: 1. Unequal distribution of ions between the extracellular fluid and cytosol. Extracellular fluid is rich in sodium and chloride ions. In cytosol, the main cation is potassium. 2. Inability of most anions to leave the cell. Most anions inside the cell cannot follow the potassium out of the cell because they are attached to molecules such as ATP and large proteins, which cannot diffuse outward. 3. Electrogenic nature of the cell. The small inward sodium leak and outward potassium leak are offset by the Na-K ATPases, pumps which help maintain the resting membrane potential by pumping out sodium as fast as it leaks in. Potassium ions are pumped inward but eventually leak back out of the cell as they move down their concentration gradient.
Adi S.
The electrochemical gradient that determines how a charged ion will move through a permeable membrane depends upon the electrical forces acting on that ion, the difference in concentration of that ion on either side of the membrane, the ratio between the charge on the ion and its atomic mass, and the combined effects of electrical forces and concentration differences across the membrane. All of the choices for this question are correct. Increasing the flow of Na+ ions into a neuron at rest (-70 mV initially) would trigger depolarization.
Md.Daniyal A.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD