Question

Blood clotting is controlled by a positive feedback loop. When tissues or blood vessels are damaged, a blood clotting cascade is activated that transforms liquid blood into a gel-like substance. The feedback loop can be activated extrinsically or intrinsically to activate a protein called factor X, a protein necessary for the blood clotting cascade to function. In the extrinsic pathway, damaged tissues release tissue factors, which interact with various clotting factors and calcium ions to activate factor X. In the intrinsic pathway, blood platelets release factor XII, which also activates factor X by interacting with various clotting factors and calcium ions.What does the data suggest about the effectiveness of the feedback loop at regulating the blood clotting cascade for someone who is deficient in calcium?A. It will be ineffective because the person will be unable to form factor X.B. It will be ineffective because the person will be deficient in red blood cells.C. It will be effective because the person's intrinsic pathway will form factor X.D. It will be effective because the person's clotting factors will interact to form calcium.

Answer 1

The process described shows no direct relation between red blood cells and the blood clotting cascade, therefore B is incorrect.

The clotting factors do not form calcium. They interact with tissue factors, as well as calcium ions interact with tissue factors too, to active factor X. Therefore, D is incorrect too.

The intrinsic pathway needs calcium ions, as they interact with factor XII to activate factor X. Therefore, C is also wrong.

Both intrinsic and extrinsic pathways needs calcium ions to activate factor X. So without calcium the cascade will be inne