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Edexcel IAL Biology 1.11 Blood clotting and cardiovascular disease

Keep precursor and active molecules distinct, place each conversion in order and connect fibrin mesh formation or enzyme inhibition to the stated outcome.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
AS

Exam points

  • Sequence thromboplastin release, thrombin activation and fibrin formation after damage.
  • Explain anticoagulant action by naming the blocked enzyme or clotting conversion.
  • Connect clot formation in a named vessel to restricted flow and cardiovascular disease.

1.11—Blood clotting and cardiovascular disease question 1

[Maximum number: 4]

Stents are used in the treatment of atherosclerosis.
Stents widen the diseased coronary artery so that blood can flow through to the heart muscle.

The diagram shows a stent.

Figure for Question 1.11—Blood clotting and cardiovascular disease question 1 — Edexcel A-Level Biology AS

Stents can damage the endothelial cells lining the artery and trigger the formation of a blood clot.

Patients who have a stent fitted are given anticoagulants.

Question (a)

(a)

Explain how damage to the endothelial cells results in the formation of thrombin.

[ 2 ]

Question (b)

(b)

The photograph shows a tropical bont tick.

Figure for Question (b) — Edexcel A-Level Biology AS

This bont tick produces a peptide called variegin.
Variegin binds to the active site of thrombin and prevents blood clotting.

[ 2 ]

Question (i)

(i)

Explain how variegin prevents blood clotting.

[ 2 ]
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