HUMAN PHYSIOLOGY
BODY FLUIDS AND CIRCULATION
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Both assertion and reason are true and reason is correct explanation of assertion.
|
|
|
Both assertion and reason are true but reason is not correct explanation of assertion.
|
|
|
Assertion is true but reason is false.
|
|
|
Assertion is false but reason is true.
|
Detailed explanation-1: -Assertion: Fibrins are formed by the conversion of inactive fibrinogens in the plasma by the enzyme thrombin. Reason: Plasma without fibrinogen and blood corpuscles is called serum. (a) Both assertion and reason are correct and the reason is the correct explanation for assertion.
Detailed explanation-2: -Fibrinogen is a soluble macromolecule, but forms an insoluble clot or gel on conversion to fibrin by the action of the serine protease thrombin, which is activated by a cascade of enzymatic reactions triggered by vessel wall injury, activated blood cells, or a foreign surface (Fig. 13.1).
Detailed explanation-3: -Enzyme thrombin catalyzes the conversion of soluble plasma proteins fibrinogen into insoluble fibrous protein fibrin.
Detailed explanation-4: -In case of an injury, the blood platelets release prothrombin in the presence of vitamin K. In the presence of calcium ions, the prothrombin is converted into thrombin by the action of the enzyme thrombokinase. The thrombin further acts on fibrinogen (inactive) and converts it into fibrin (active).
Detailed explanation-5: -Thrombin is responsible for the conversion of inactive fibrinogens to fibrins.