ATI TEAS (Test of Essential Academic Skills) Version 7ScienceMedium
A research team is studying the process by which a cell engulfs large particles, such as bacteria or cellular debris, by extending its plasma membrane around them and forming a vesicle. Which of the following terms describes this specific active transport mechanism?
- APinocytosis
- BFacilitated diffusion
- CPhagocytosis
- DExocytosis
Show answer & explanationAnswer & explanation
Correct answer: C. Phagocytosis
Phagocytosis is a specific type of endocytosis where a cell engulfs large particles, such as bacteria, other cells, or cellular debris, by forming a phagosome (a type of vesicle). This process is critical for immune defense and nutrient acquisition.
Why the other options are wrong
- A. Pinocytosis is 'cell drinking,' the engulfment of extracellular fluid and dissolved solutes, not large particles.
- B. Facilitated diffusion is a passive transport mechanism that uses transport proteins to move substances across the membrane down their concentration gradient, not engulfment.
- D. Exocytosis is the process by which cells release substances from inside the cell to the outside, the opposite of engulfment.
Phagocytosis
A type of endocytosis in which a cell engulfs large particles, such as bacteria or cellular debris, by extending pseudopods and forming a vesicle.
- Known as 'cell eating'.
- Involves the formation of a phagosome.
- Crucial for immune cells like macrophages.
Memory trick: Phago-cytosis means 'fag' (eat) large particles.