Question

a&p flix: membrane transport (multiple choice)
5 parts 0.8 of 1 point

a vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. this statement
describes ______.

simple diffusion

active transport

endocytosis

exocytosis

facilitated diffusion

Explanation:

• Simple diffusion: Movement of molecules from high to low concentration without a membrane protein or vesicle. Eliminate.
• Active transport: Movement against concentration gradient, using energy, often via pumps, not vesicles. Eliminate.
• Endocytosis: Process of taking substances into the cell via vesicle formation (opposite of releasing out). Eliminate.
• Exocytosis: Process where a vesicle fuses with the plasma membrane to release its contents outside the cell (extracellular fluid), matching the description.
• Facilitated diffusion: Movement via membrane proteins, no vesicle involved. Eliminate.

Answer:

D. exocytosis