Question

An axonal process 2 meter long is originating in spinal cord and terminating in the muscles of toes. If the average velocity of a vesicle is \(1\ \mu\text{m/s}\) how long does it take a vesicle to move from a cell body in the spinal cord to the axonal tip in the toes?

• A. $2 \times 10^{5}$ sec \
• B. $2 \times 10^{3}$ sec \
• C. $2 \times 10^{4}$ sec \
• D. $2 \times 10^{6}$ sec

Hint:

Always convert your units first! Since 1 meter equals $10^{6}$ micrometers, a 2-meter axon spans $2 \times 10^{6}\ \mu\text{m}$. At a speed of $1\ \mu\text{m/s}$, it takes exactly $2 \times 10^{6}$ seconds.

Answer 1

The Correct Option is D