A Membrane Potential Is Plotted Over Time in the Following

question 11

Multiple Choice

A membrane potential is plotted over time in the following graph. The Nernst equilibrium potentials for four ions (A to D) that affect the membrane potential in this system are indicated in the graph. What happened in the time period indicated by a question mark?

• A) Channels conducting ion A opened.
• B) Channels conducting ion B opened.
• C) Channels conducting ion C opened.
• D) Channels conducting ion D opened.
• E) Channels conducting ion A and C opened.

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Definitions:

Coleoptile

Of monocots, a rigid sheath that protects the plumule (embryonic shoot) as it grows up to the soil surface.

Radicle

The first part of a seedling to emerge during the germination process, which develops into the primary root.

Phototropism

Directional response to light.

Auxin

Plant hormone that causes cell enlargement; also has a central role in growth and development by coordinating the effects of other hormones.