Some antibiotics act as carriers that bind an ion on one side of a membrane, diffuse through the membrane, and release the ion on the other side. The conductance of a lipid-bilayer membrane containing a carrier antibiotic decreased abruptly when the temperature was lowered from 40°C to 36° C. In contrast, there was little change in conductance of the same bilayer membrane when it contained a channel-forming antibiotic. Why?

Some antibiotics act as carriers that bind an ion on one side of a membrane, diffuse through the membrane, and release the ion on the other side. The conductance of a lipid-bilayer membrane containing a carrier antibiotic decreased abruptly when the temperature was lowered from 40°C to 36° C. In contrast, there was little change in conductance of the same bilayer membrane when it contained a channel-forming antibiotic. Why?

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter3: The Plasma Membrane And Membrane Potential

Section: Chapter Questions

Problem 2TAHL: Assume that a membrane permeable to Na+ but not to Cl- separates two solutions. The concentration of...

See similar textbooks

Similar questions

Using the answer code on the right, indicate which membrane component is responsible for the function in question: 1. channel formation____________________________________ (a) lipid bilayer 2. barrier to passage of water- __________________ (b) proteins soluble substances ____________________________________ (c) carbohydrates 3. receptor sites 4. membrane fluidity 5. recognition of self 6. membrane-bound enzymes 7. structural boundary 8. carriers
During an investigation on membrane transport, a researcher exposed bacterial cells to different concentrations of two different solutes: A and B. The rate of transport of each solute into cells isrepresented in the graphSolute ASolute BSolute ConcentrationWhich of the following best explains the greater rate of transport for solute A than for solute B at higher solute concentrations?A Solute A is being transported by simple diffusion, which does not rely on membrane proteins to control the rate of transportSolute A is being transported by active transport, which uses ATP and has higher rates of transport than passive transportSolute A is being transported by facilitated diffusion, which uses membrane proteins to increase the rate of transportRate of Transport
List two ways that channels differ from transporters? What type of molecules do channels usually transport?
If you made a hematocrit in two tubes. Tube A is made of 0.60M NaCl, and Tube B is made of 1.00M of NaCl, describe how the cell would respond in these solutions? Which would have a higher rate of osmosis? If the cell is permeable to NaCl, which would have a higher rate of diffusion?
Describe ONE modification that could happen to the phospholipids in a membrane that would increase the permeability of the membrane to small non-polar molecules such as oxygen gas. Explain why this modification would increase membrane permeability.
The tight binding sites required for ion selectivity should slow the progress of ions through a channel, yet ion channels achieve rapid rates of ion transport. How is this paradox resolved?
A cell creates a H+ gradient across a membrane- in other words, a situation is created were the concentration of H+ is higher on one side then the other of a membrane. How can this H+ concentration gradient be used to do work (that the cells needs to do)?
If the concentration of a solute is the same both inside and outside the cell, what might you expect with regard to its transport by a membrane protein? A. Since there is no concentration gradient, no transport either in or out of the cell is possible. B. The transport protein has been saturated. C. The solute must be phosphorylated with a phosphate group from ATP before further transport can occur. D. Movement of the solute across the membrane could occur and cause accumulated on one side of the membrane by an active transport protein. The concerted model of allosteric regulation is different from the sequential model, because: A. The concerted model is used to explain homotropic effects B. The sequential model is used to explain heterotropic effects C. Both A and B D. Neither A nor B
Which is not required for passive transport across a membrane (select all that apply and explain why): a concentration gradient a cotransported ion energy a protein channel
The primary function of the kidney is to exchange molecules across a membrane between the blood and the urine. One type of kidney cell has a basic rectangular shape, except for a single surface, which is lined with tiny, finger-like projections that extend into the surrounding extracellular space. Which of the following best explains the advantage these projections provide the cell? The projections increase the selectivity of the membrane because the small size of the projections limits the number of transport proteins that can be embedded in the membrane. The projections increase the volume of the cell without affecting the surface area, which increases the metabolic needs of the cell. The projections increase the surface area–to-volume ratio of the cell, which allows for more efficient nutrient exchange with the environment. The projections increase the speed at which an individual molecule can move,…
Describe the difference between carrier proteins and channel proteins. What is required for the passive transport of molecules through these membrane proteins?
Here is a chloride cell in the gill epithelium of a fish. For reference, NKA = Na+/K+ ATPaseNKCC = Na+/K+/Cl- cotransporter. CFTR allows for movement of Cl- from inside the cell out into the water down a concentration gradient. Which of the following would be true of CFTR? A. It is a primary active transporter. B. It is a symporter. C. It is a secondary active transporter. D. It is a channel that allows for facilitated diffusion.