A Level Biology Practice Exam

In which process do cells take in liquid materials?

1. Phagocytosis

2. Exocytosis

3. Pinocytosis

4. Diffusion

The correct answer is: Pinocytosis

The correct answer is indeed the process known as pinocytosis. This is a type of endocytosis specifically related to the uptake of liquid materials and small solutes. During pinocytosis, cells engulf extracellular fluid along with any dissolved substances. This occurs through the invagination of the cell membrane, which forms a vesicle that brings the liquid into the cell. In contrast, phagocytosis involves the uptake of large particles, such as bacteria or dead cells, rather than liquids. Exocytosis refers to the process by which cells expel materials from the interior to the exterior, essentially the reverse of endocytosis. Diffusion is a passive transport process where molecules move from an area of higher concentration to an area of lower concentration, which does not specifically involve the active ingestion of liquids. Thus, when considering the uptake of liquid materials, pinocytosis is the clear and accurate process.