Sodium and potassium ion channels have several negatively charged residues at the entry to the channel....

Sodium and potassium ion channels have several negatively charged residues at the entry to the channel. On what basis do K+ channels specifically select for K+ ions? (In other words, why dont K+ channels enable Na+ ions to cross the membrane?)

-ionic radius, Na+ is to small

-energy cost, it is to energetically costly to dehydrate Na+

-charge, Na is slightly more electronegative than K and does not interact with the channel carbonyl groups

-charge, Na is slightly less electronegative than K and does not interact with the channel carbonyl groups

-ionic radius, Na+ is too big

Solutions

Expert Solution

energy cost, it is too energetically costly to dehydrate Na+

ionic radius, Na+ is too small

gladiator answered 1 year ago

Next > < Previous

Related Solutions

If a ligand-gated channel (ionotropic receptor) was activated by a negatively charged ion with a negative...

If a ligand-gated channel (ionotropic receptor) was activated by a negatively charged ion with a negative equilibrium potential, would it result in an Excitatory post synaptic potential or an inhibitory post synaptic potential?

Digitalis affects what protein? A) potassium ion channels b)ligand gated channels c)sodium/potassium ATPase d)calcium ATPase e)sodium...

Digitalis affects what protein? A) potassium ion channels b)ligand gated channels c)sodium/potassium ATPase d)calcium ATPase e)sodium ion channels

4. The movement of sodium and potassium ions via sodium channel and potassium channel proteins is...

4. The movement of sodium and potassium ions via sodium channel and potassium channel proteins is A. Active Process B. Passive process C. Both D. None of the above 5. The Na/K voltage gated channel protein uses __________ to move sodium and potassium across the plasma membrane. 6. The ion, which conduct electricity, is: a. A charged atom b. a charged molecule c. Both A and B are correct d. none of these are correct 7. In a resting membrane...

Glycogen phosphorylase and the sodium-potassium pump both have amino acid residues that can be phosphorylated. In...

Glycogen phosphorylase and the sodium-potassium pump both have amino acid residues that can be phosphorylated. In the case of the sodium-potassium pump it is Asp369. In glycogen phosphorylase, it is Ser14 that gets phosphorylated. Compare and contrast the role of phosphorylation for both proteins with regards to how the proteins function.

How does hydration of sodium and potassium play an important role in the selectivity of the potassium channel ?

Are voltage gated sodium channels, and voltage gated potassium channels considered secondary active transporters? If not...

Are voltage gated sodium channels, and voltage gated potassium channels considered secondary active transporters? If not then what are they called, and could you please explain what a secondary active transporter is and include a common example of one?

A membrane spanning protein that is a channel for potassium ion transport is made up of...

A membrane spanning protein that is a channel for potassium ion transport is made up of six copies of a single polypeptide. Potassium ions are transported across the membrane using the channel. In your experiments with the gene encoding the channel proteins, you have isolated a mutant of the potassium channel that transports very small amounts of potassium compared to the wild type. You perform SDS-PAGE electrophoresis with proteins from the mutant and proteins from the wild type. In the...

A membrane spanning protein that is a channel for potassium ion transport is made up of...

A membrane spanning protein that is a channel for potassium ion transport is made up of six copies of a single polypeptide. Potassium ions are transported across the membrane using the channel. What types of amino acids do you expect to find on the potassium ion channel polypeptides next to the heads of the membrane lipids? (multiple answers) a. Nonpolar b. Positively charged c. Polar d. Negatively charged

Which statement is INCORRECT regarding voltage-gated potassium channels? - The gating of the channel involves movements...

Which statement is INCORRECT regarding voltage-gated potassium channels? - The gating of the channel involves movements of transmembrane helices. - The K+ is transported down its concentration gradient. - A cytoplasmic inactivation peptide blocks the channel in response to voltage changes. - K+ coordinates to C=0 groups in the channel. - All of the above.

1. Ion channels contain a selectivity filter that (choose best answer) a) selects for positively charged...

1. Ion channels contain a selectivity filter that (choose best answer) a) selects for positively charged ions by virtue of the negatively charged amino acids lining the pore, but allows similar ions through, like Na+ and K+. b) selects for size of ions based on interactions with the ion transport protein. c) binds with extreme sensitivity to their specific ion, akin to an enzyme forming a specific binding site for a substrate. d) selects for ions based on size and...

Subjects