This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Microbiology
[{'content': 'True about sex pilus \nSelect and explain. \nA. Hollow tubular structure binding bacteria during conjugation, B. During conjugation host DNA is always transferred, C. Plasmid is transferred always, D. ?', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans: a) (Hollow tubular....) Ref: Medical microbiology Jawetz 23nl ed. Baily & Scott's diagnostic microbiology 12th edCONJUGATION* Process where male/ donor bacterium mates or makes physical contact with female/ recipient bacterium & transfers genetic elements into it. 1st described by Lederberg & Tatum in E coli called K12.* Plasmids are the genetic elements most frequently transferred by conjugation. But hostDNA& transposons all can be transferred by conjugation.* Fertility factor carried on plasmid is designated F+. This plasmid confers certain donor characteristics upon cells; these characteristics include a sex pilus: an extracellular multimeric protein extrusion that attaches donor cells to recipient organism lacking F factor.* Plasmid DNA in donor replicates & a copy of it passes from door to recipient along sex pilus. Thus recipient becomes F+& can conjugate with other cells.* Along with plasmid DNA, a portion of host DNA is sometimes transferred.* When F exists in some cells in intergrated state with host chromosome - HFr", 'role': 'assistant'}]