This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Which of the following is not used as vector in genetics? 
Select and explain. 
A. Adeno virus, B. Proteosome, C. Liposome, D. Retrovirus
B: Proteosome
Answer: B: Proteosome 
Explanation: VECTORS : The gene is trasferred to acarrier ,known as a vector.Most commonly used vectors are plasmids.Plasmids are circular double -stranded DNA molecuels seen inside bacteria. Different vector systems used for gene delivery are : Retro viruses , Adenoviruses , Adeno associated viralvectors and Herpes simplex virruses.Non -virus systems include Liposomes , Plasmids and physical methods. Proteosomes are protein complexes which degrade unneeded or damaged proteins by proteolysis , a chemical reaction that breaks petide bonds.Enzymes that help such reactions are called proteolysis. REF :DM VASUDEVAN TEXTBOOK ,7th EDITION , Page no :629.