The Swellings or Knobs at the End of the Axon

question 33

Multiple Choice

The swellings or knobs at the end of the axon are called ________.

• A) presynaptic terminals
• B) synaptic vesicles
• C) synapses
• D) receptor sites

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Definitions:

Concentration Gradient

A variation in the concentration of a substance across a distance, leading to the movement of particles from an area of high concentration to one of lower concentration.

Carrier Molecules

Proteins that facilitate the transport of substances across a cell membrane without modification of the transported substance.

Facilitated Diffusion

A transport process where molecules pass across cell membranes through protein channels without the expenditure of cellular energy.

Active Transport

The movement of substances across cell membranes against a concentration gradient, requiring energy expenditure by the cell.