A Paramecium "knows" when it has encountered a noxious substance and backs off to veer away.As a one-celled organism,how does it "know" to do this?
A)The macronucleus has DNA coding that determines this reaction.
B)The micronucleus is dedicated to controlling just such responses.
C)This cell is essentially a small neuron,or nerve cell.
D)This is a rather simple stimulus that changes the electrical potential difference across the cell membrane and depolarization of the membrane results in cilia reversing their direction of beating.
E)None of the choices is correct.

Question

Quizplus · Accepted Answer

In Paramecium, encountering a noxious substance is a simple stimulus that changes the electrical potential difference across the cell membrane. This depolarization of the membrane causes the cilia to reverse their direction of beating, resulting in the cell backing off to veer away from the substance. This response does not involve the micronucleus or macronucleus, and Paramecium is not a neuron or nerve cell.

A Paramecium "Knows" When It Has Encountered a Noxious Substance