Neco 2019 Biology Question 50

Practice objective / multiple choice question 50 from the 2019 Neco Biology examination.

Neco 2019 Biology Objective / Multiple Choice Medium Difficulty
Question 50 NECO • 2019 • BIOLOGY • objective

Neuron X is a myelinated axon with a diameter of \(5\ \mu\text{m}\) and conducts impulses at \(50\ \text{m/s}\). For unmyelinated axons, conduction speed (in m/s) is proportional to the diameter with a constant of proportionality \(k = 1\ \text{m·s}^{-1}\!\!/\mu\text{m}\). For myelinated axons, the speed is ten times greater for the same diameter, i.e., \(v = 10k d\). Neuron Y is unmyelinated and conducts at \(30\ \text{m/s}\). Determine the diameter of Neuron Y and compute the time taken for an impulse to travel a distance of \(1\ \text{m}\) in each neuron.

Answer Options

Correct Answer A. Diameter of Neuron Y = 30 µm; time for 1 m: Neuron X = 0.02 s, Neuron Y = 0.033 s (approx).
B. Diameter of Neuron Y = 15 µm; time for 1 m: Neuron X = 0.02 s, Neuron Y = 0.067 s (approx).
C. Diameter of Neuron Y = 60 µm; time for 1 m: Neuron X = 0.025 s, Neuron Y = 0.017 s (approx).
D. Diameter of Neuron Y = 45 µm; time for 1 m: Neuron X = 0.018 s, Neuron Y = 0.022 s (approx).
Correct Answer
A
Correct Option:
Diameter of Neuron Y = 30 µm; time for 1 m: Neuron X = 0.02 s, Neuron Y = 0.033 s (approx).

About This Question

This is Neco 2019 Biology Question 50. It is one of the objective questions from the 2019 Neco Biology examination.

Difficulty level: Medium .

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