False statement about the following cellular phenomenon is?
Correct Answer: Clathrin mediated endocytosis is involved in taking up of dead tissues and bacteria
Description: Ans. B. Clathrin mediated endocytosis is involved in taking up of dead tissue and bacteriaa. Endocytosis is the reverse of exocytosis. There are various types of endocytosis named for the size of particles being ingested as well as the regulatory requirements for the particular process. These include phagocytosis, pinocytosis, clathrin-mediated endocytosis, caveolae-dependent uptake, and non clathrin/non caveolae endocytosis.b. Phagocytosis ("cell eating") is the process by which bacteria, dead tissue, or other bits of microscopic material are engulfed by cells such as the polymorphonuclear leukocytes of the blood. The material makes contact with the cell membrane, which then invaginate. The invagination is pinched off, leaving the engulfed material in the membrane- enclosed vacuole and the cell membrane intact. Pinocytosis ("cell drinking") is a similar process with the vesicles much smaller in size and the substances ingested are in solution. The small size membrane that is ingested should not be misconstrued; cells undergoing active pinocytosis (eg, macrophages) can ingest the equivalent of their entire cell membrane in just 1 hour.c. Clathrin-mediated endocytosis occurs at membrane indentations where the protein clathrin accumulates. Clathrin molecules have the shape of triskelion's, with three "legs" radiating from a central hub. As endocytosis progresses, the clathrin molecules form a geometric array that surrounds the endocytotic vesicle. At the neck of the vesicle, the GTP binding protein dynamin is involved, either directly or indirectly, in pinching off the vesicle. Once the complete vesicle is formed, the clathrin falls off and the three-legged proteins recycle to form another vesicle. The vesicle fuses with and dumps its contents into an early endosome.d. From the early endosome, a new vesicle can bud off and return to the cell membrane. Alternatively, the early endosome can become a late endosome and fuse with a lysosome in which the contents are digested by the lysosomal proteases. Clathrin-mediated endocytosis is responsible for the internalization of many receptors and the ligands bound to them including, for example, nerve growth factor and low-density lipoproteins. It also plays a major role in synaptic function.
Category:
Physiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now