Question

Structures that form the voltage sensors of K channels Group of answer choices extend into the intracellular space. are embedded in the cell membrane. are located within the channel pore. extend into the extracellular space. are embedded in the cell membrane but extend into the extracellular space when the membrane is depolarized.

Answer 1

are embedded in the cell membrane

Step-by-step explanation:

Voltage-gated ion channels are transmembrane proteins activated by changes of the electrical potential across the plasma membrane. Structurally, voltage-gated Potassium (K) channels are composed of six transmembrane helices where amino- and carboxyl-terminal peptides are localized intracellularly (in the cytoplasm). The Helices 1 to 4 (H1-H4) comprise the voltage sensor domain that forms an anti-parallel helical bundle. H4 has many positively charged amino acids (Arg and Lys residues) which are key to the voltage-sensing function. Finally, Helices 5 and 6 (H5-H6) form the channel pore which is localized in the center of the protein.