Multiple Choice
In the context of exocytosis at a chemical synapse, where are neurotransmitters stored in a presynaptic neuron before they are released?
30
views
13. Intracellular Protein Transport
Exocytosis
Multiple Choice
In cell biology, is exocytosis considered active transport or passive transport?
A
Passive transport, because exocytosis is simply diffusion through membrane pores.
B
Neither; exocytosis is a form of osmosis driven only by water potential differences.
C
Active transport, because vesicle fusion with the plasma membrane requires energy (e.g., ATP) and cytoskeletal machinery.
D
Passive transport, because substances move down their concentration gradient through the lipid bilayer without energy input.
Verified step by step guidance1
Step 1: Understand the definitions of active and passive transport. Active transport requires energy input (usually ATP) to move substances against their concentration gradient, while passive transport does not require energy and moves substances down their concentration gradient.
Step 2: Define exocytosis in cell biology. Exocytosis is the process by which cells transport materials in vesicles that fuse with the plasma membrane to release their contents outside the cell.
Step 3: Analyze whether exocytosis requires energy. Since vesicle movement and fusion involve cytoskeletal elements and motor proteins, ATP is consumed during this process, indicating energy usage.
Step 4: Compare exocytosis to passive transport mechanisms. Passive transport involves diffusion or osmosis directly through the membrane or pores without energy, which is different from vesicle-mediated transport.
Step 5: Conclude that exocytosis is a form of active transport because it requires energy to move substances out of the cell via vesicle fusion, rather than relying on passive diffusion.
Related Videos
Related Practice
