Question

Experiments where axons grow on laminin have shown that when the neurons (and their axons) lack myosin IIB, what happens?

1) The axons grow faster
2) The axons grow slower
3) The axons do not grow at all
4) The axons grow in a different direction

Answer 1

Without myosin IIB, axons grow slower because myosin IIB is essential for proper axonal growth mechanisms, which are particularly dependent on cellular processes facilitated by the protein.

Step-by-step explanation:

When neurons and their axons lack myosin IIB, the axons typically grow slower. This is because myosin IIB plays a role in the contraction processes involved in cell movements, including the extension of neuronal growth cones that are critical for axon guidance. Experiments have shown that when neurons (and their axons) lack myosin IIB and are grown on laminin, the axons do not grow at all.

Myosin IIB is a motor protein that plays a role in axon growth and development. Without myosin IIB, the axons are unable to grow or extend properly.

For example, studies have shown that when myosin IIB is depleted in mouse embryonic neurons, axon growth is significantly impaired or completely halted.Laminin, a protein found in the extracellular matrix, supports axon growth by providing an adhesive surface for the neurons to attach to and extend their axons. However, without sufficient myosin IIB, the mechanics of this growth may be impaired, leading to decreased growth rates of the axons.