This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
The cytoplasmic membrane of bacteria is responsible for - 
Select and explain. 
A. Slective permeability, B. Motility, C. Cell division, D. Conjunction
A: Slective permeability
Answer: A: Slective permeability 
Explanation: The cytoplasmic membrane is a thin layer lining the inner surface of the cell wall and separating it from the cytoplasm. It acts as a semipermeable membrane controlling the flow of metabolites to and from the protoplasm. Passage through the membrane is not solely a function of the molecular size of the paicles but depends in many cases on the presence in the membrane of specific enzymes (pereases). Electron microscopy shows the presence of 3 layers constituting a unit membrane structure. Chemically the membrane consists of lipoprotein with a small number of carbohydrates. Sterols are absent except in mycoplasma Ref: Ananthanarayan & paniker's Textbook of Microbiology 9th edition pg no 16