This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Both antibody-dependent and independent complement pathway converge on which complement component? \nSelect and explain. \nA. C5, B. C3, C. Clq, D. C8', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Complement is a collective term that describes a system of about 20 proteins, many of which are enzyme\xa0precursors. All these are present normally among the plasma proteins in the blood as well as among the proteins\xa0that leak out of the capillaries into the tissues.\nThey are usually inactive i.e. enzyme precursors\nThey are activated by two pathways\ni. Classic pathway\nii. Alternate pathway\nClassic pathway -\xa0The classical pathway is initiated by an antigen-antibody reaction.\nAlternative pathway\n\nAlternative pathway complement activation does not require the interaction of complement with an antigen /antibody complex. Rather a bacterial lipopolysaccharide (LPS, endotoxin) and other general bacterial\xa0substances (also immunoglobulin A aggregates) can activate complement.\nIn both the classical and alternative pathways a key outcome is the conversion of the C3 component of\xa0complement into C3a and C3b proteins.\nBoth the pathways follow different course only up to the activation of C3. Activation or splicing of the C3 is the\xa0convergence point of both the pathways, after which both the pathways follow the same course.', 'role': 'assistant'}]