This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
Proteins are transported into the cell by? 
Select and explain. 
A. Pinocytosis, B. Osmosis, C. Active diffusion, D. Passive diffusion
A: Pinocytosis
Answer: A: Pinocytosis 
Explanation: Ans. a (Pinocytosis). (Ref. Ganong, Physiology, 21st/pg.29)Pinocytosis ("Cell drinking")# It is the process by which proteins are taken into the cell. The substance ingested are insoluble & not seen by microscope.# Endocytosis: It is a process by which a molecule is taken into the cell.# Endocytosis can be of 2 types: Phagocytosis & pinocytosis.# Endocytosis can be constitutive or clathrin-mediated, which is responsible for internalisation of many receptors & ligands binding to them. e.g. NGF, LDL, Synaptic function.