A Level Biology Practice Exam

What is described by exocytosis?

1. The bulk transport of materials into cells

2. The fusion of vesicles with the cell membrane to release materials outside

3. The process of cellular respiration

4. A method of nutrient absorption

The correct answer is: The fusion of vesicles with the cell membrane to release materials outside

Exocytosis is defined as the biological process in which vesicles within a cell fuse with the cell membrane and release their contents outside the cell. This mechanism is crucial for various cellular functions, including the secretion of hormones, neurotransmitters, and enzymes. During exocytosis, the vesicle membrane merges with the plasma membrane, facilitating the transfer of materials into the extracellular space. The accuracy of this description highlights the role of exocytosis in maintaining cellular communication and homeostasis, as well as its involvement in transporting large molecules that cannot pass through the lipid bilayer directly. The specificity of exocytosis to releasing materials from the cell distinguishes it from other transport processes. Understanding this process is essential for grasping how cells interact with their environment and regulate the substances they release.