Gce Model Questions Vol1 2025 Biology Question 31

Practice objective / multiple choice question 31 from the 2025 Gce Model Questions Vol1 Biology examination.

Gce Model Questions Vol1 2025 Biology Objective / Multiple Choice Medium Difficulty
Question 31 GCE_MODEL_QUESTIONS_VOL1 • 2025 • BIOLOGY • objective

A motor neuron to a skeletal muscle fibre consists of a 0.5 m long myelinated segment where the impulse speed is \(120\ \text{m\,s}^{-1}\) and a 0.02 m long unmyelinated segment where the speed is \(2\ \text{m\,s}^{-1}\). The signal passes through two chemical synapses, each introducing a delay of \(0.5\ \text{ms}\). Calculate the total time taken for the impulse to travel from the neuron's cell body to the muscle fibre. Is this total time less than the \(5\ \text{ms}\) required for a rapid withdrawal reflex? State yes or no and give the difference (in ms) between the calculated time and the 5 ms threshold.

Answer Options

A. No; the total time is about 16.5 ms, which exceeds the 5 ms threshold by roughly 11.5 ms.
Correct Answer B. No; the total time is about 15.2 ms, which exceeds the 5 ms threshold by roughly 10.2 ms.
C. Yes; the total time is about 4.8 ms, which is below the 5 ms threshold by roughly 0.2 ms.
D. No; the total time is about 12.0 ms, which exceeds the 5 ms threshold by roughly 7.0 ms.
Correct Answer
B
Correct Option:
No; the total time is about 15.2 ms, which exceeds the 5 ms threshold by roughly 10.2 ms.

About This Question

This is Gce Model Questions Vol1 2025 Biology Question 31. It is one of the objective questions from the 2025 Gce Model Questions Vol1 Biology examination.

Difficulty level: Medium .

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