This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Medicine
[{'content': 'Which among the following factors level is not altered in vit K deficiency? \nSelect and explain. \nA. Prothrombin, B. Factor VIII, C. Factor VII, D. Factor X', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans b: (Factor VIII) Ref: Harrison p.367, 728-730Coagulation factors II, VII, IX, X and protein C, S and Z are dependent on Vit K for post translational modification. Vit K also for bone protein osteocalcin and vascular smooth muscle protein- matrix glaproteinFew more points:* Gamma carboxy glutamic acid residues in the Vit k dependent factors will help in their critical action including calcium and phospholipid binding* Mutations in Vit k epoxide reductase complex 1 (VKORC1) andgene encoding gamma glutamyl carboxylase(GGCX) result in defect free enzyme and there in Vit K dependent factors with decreased activity.* Causes mild to severe bleeding episodes from birth* Prolongation of PT is the most common and earliest finding in Vit K deficiency. Factor V11 has the shortest tl/2, so PT prolonged much before changes in aPTT', 'role': 'assistant'}]