Gce Model Questions Vol1 2018 Biology Question 2

Practice objective / multiple choice question 2 from the 2018 Gce Model Questions Vol1 Biology examination.

Gce Model Questions Vol1 2018 Biology Objective / Multiple Choice Medium Difficulty
Question 2 GCE_MODEL_QUESTIONS_VOL1 • 2018 • BIOLOGY • objective

A motor neuron's axon is 0.5 m long. When the axon is myelinated an impulse travels at 80 m s\(^{-1}\); when it is demyelinated the speed falls to 20 m s\(^{-1}\). A simple reflex requires the impulse to travel from the spinal cord to the muscle and back along the same axon. Calculate (a) the total time taken for the reflex when the axon is myelinated and when it is demyelinated, (b) the difference in time between the two conditions, and (c) the percentage increase in time caused by demyelination.

Answer Options

A. The reflex takes 13 ms when myelinated and 52 ms when demyelinated; the demyelinated condition is 39 ms slower, a 300 % increase.
B. The reflex takes 14 ms when myelinated and 56 ms when demyelinated; the demyelinated condition is 42 ms slower, a 300 % increase.
C. The reflex takes 10 ms when myelinated and 40 ms when demyelinated; the demyelinated condition is 30 ms slower, a 300 % increase.
Correct Answer D. The reflex takes 12.5 ms when myelinated and 50 ms when demyelinated; the demyelinated condition is 37.5 ms slower, a 300 % increase.
Correct Answer
D
Correct Option:
The reflex takes 12.5 ms when myelinated and 50 ms when demyelinated; the demyelinated condition is 37.5 ms slower, a 300 % increase.

About This Question

This is Gce Model Questions Vol1 2018 Biology Question 2. It is one of the objective questions from the 2018 Gce Model Questions Vol1 Biology examination.

Difficulty level: Medium .

View More Gce Model Questions Vol1 2018 Biology Questions More Gce Model Questions Vol1 Practice Questions Back to Questions

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Chat with Support