The clotting cascade
"The clotting cascade" is a free, interactive Class 11 Biology simulation for NEET, built on the NCERT section "Coagulation of blood" in Body Fluids and Circulation. Injury or platelet factors start a cascade: thrombokinase turns prothrombin into thrombin, thrombin turns fibrinogen into a fibrin mesh that traps cells; remove Ca2+ and it stalls. NEET has asked about this idea 3 times in 10 years of papers.
From the lesson Coagulation of blood in Body Fluids and Circulation. Change the values and watch what happens.
What it shows
NCERT §15.1.4
Injury or platelet factors start a cascade: thrombokinase turns prothrombin into thrombin, thrombin turns fibrinogen into a fibrin mesh that traps cells; remove Ca2+ and it stalls.
Controls
4 to try
- Toggleplatelets release factors
- ToggleCa2+ present / chelated
- Sliderfibrinogen 0–4 g/L
- Buttonmake a cut
Try this
Seal the cut with a fibrin mesh in under 6 s, then find which single switch stops the clot at the prothrombin step.
Common mistake
Thrombin forms directly from fibrinogen; serum = plasma.
In NEET
10 years of papers
Asked 3 times in 10 years of NEET.
See the past questions: Body Fluids and Circulation (chapter)
The idea behind it
NCERT §15.1.4
- Blood clots in response to injury or trauma; this stops excessive loss of blood.
- The dark reddish-brown scum over a cut is a clot (coagulum): a mesh of threads called fibrin in which dead and damaged formed elements are trapped.
- Fibrin is made from inactive fibrinogen in plasma by the enzyme thrombin.
- Thrombin itself is made from another inactive plasma substance, prothrombin. This step needs an enzyme complex, thrombokinase.
- Thrombokinase forms through a cascade: a chain of linked enzyme reactions involving several factors present in plasma in an inactive state.
- Injury stimulates platelets to release factors that set the cascade going; factors released by damaged tissue at the site can also start it.
- Calcium ions play a very important role in clotting.
Questions
4 answers
- What does the "The clotting cascade" simulation show?
- Injury or platelet factors start a cascade: thrombokinase turns prothrombin into thrombin, thrombin turns fibrinogen into a fibrin mesh that traps cells; remove Ca2+ and it stalls.
- What mistake does the "The clotting cascade" simulation fix?
- A common mistake it clears up: thrombin forms directly from fibrinogen; serum = plasma.
- Has NEET asked about this idea?
- Yes. NEET has asked about this idea 3 times in 10 years of papers.
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Coagulation of blood" in Body Fluids and Circulation (Class 11 Biology).
Embed this simulation
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