Voltage-Gated Cation Channels in the Plasma Membrane of a Neuron

question 33

Multiple Choice

Voltage-gated cation channels in the plasma membrane of a neuron open when the membrane potential passes a threshold value that is about 20 mV above the resting potential. This corresponds to a change of about 4 × 10⁶ newtons per coulomb in the magnitude of the electric field across the membrane compared to the resting state. The tetrameric channels have a voltage-sensing helix S4 in each of their four subunits. Most S4 helices contain seven residues with positively charged side chains. The charge carried by each such residue is about 1.6 × 10-¹⁹ coulombs. By reaching threshold depolarization, what are the magnitude and the direction of the collective force that the four S4 helices in the channel experience as a result of the change in the electric field? The force that particles of charge q in an electric field E experience is calculated as F = q.E.

• A) 18 pN, toward the cell interior
• B) 18 pN, toward the cell exterior
• C) 90 pN, toward the cell interior
• D) 90 pN, toward the cell exterior
• E) 45 pN, toward the cell interior

Distinguish between leadership and management, and their respective focuses and outcomes.

Understand the ethical implications and responsibilities inherent in leadership.

Differentiate between assigned and emergent leaders within organizations.

Analyze contemporary approaches and paradigms in leadership studies, including the emphasis on followership.

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Definitions:

Equal Employment

A principle that mandates equal job opportunities for all, regardless of race, gender, or other non-merit factors.

Breastfeed

The act of feeding a baby or young child milk from a woman's breast, which is a recommended practice for infant nutrition.

Pregnant Woman

A pregnant woman is a female who is in the state of carrying a developing embryo or fetus within her uterus.

Common Law

A legal system based on customs, court decisions, and precedent rather than statutory laws.