Which Features Allow the KcsA Channel to Selectively Transport K⁺

question 2

Multiple Choice

Which features allow the KcsA channel to selectively transport K⁺?
(I) The entrance of the channel contains hydrophobic residues which forces the removal of waters of hydration.
(II) It is attracted to the entrance of the channel via electrostatic interactions.
(III) The "selectivity filter" involves a narrowing of the channel,allowing only dehydrated K⁺ access.
(IV) As K⁺ is transported through the channel it interacts with −C=O groups from the protein.

• A)I,II,III,IV
• B)II,III,IV
• C)II,III
• D)III,IV
• E)I,III

---

Definitions:

Validity

The extent to which a method or procedure measures what it is supposed to measure.

Psychometric View

An approach in psychology that focuses on the measurement of mental functions, intelligence, abilities, and attitudes through the use of tests and questionnaires.

Intelligence

The capacity for learning, understanding, and applying knowledge and skills, and the ability to adapt to new situations.

Predictive Validity

The degree to which a score obtained from a test or scale forecasts an individual’s future achievements on a similar activity.