Choose the odd one out from the following terms and name the category to which the others belong:
Prothrombin, Thrombin, Fibrinogen, Albumin
Topic: Blood clotting proteins
Answer
Odd one out: ALBUMIN. Category of the others: PLASMA PROTEINS INVOLVED IN BLOOD CLOTTING.
Prothrombin, thrombin and fibrinogen are all part of the CLOTTING mechanism: PROTHROMBIN is converted into THROMBIN THROMBIN then converts FIBRINOGEN into fibrin, whose threads form the mesh of the clot
ALBUMIN is also a plasma protein, but its job is quite different — it maintains the OSMOTIC PRESSURE of the blood and transports substances. It plays no part in clotting.
THE CARE NEEDED HERE: all four are plasma proteins, so "plasma proteins" is NOT a category that separates three from one. The category must be the narrower one — clotting factors. When every term shares an obvious label, look for a finer one.