9.1.17Transport in Animals
Conversion of Fibrinogen — Cambridge IGCSE Biology 0610 Revision Notes & Topical Questions
5 min read 5 parts Lesson 9 of 9 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Part 1 of 5Why Blood Clots
When the skin is cut or punctured, the body must stop bleeding and keep microorganisms out.
Preventing blood loss
- Preventing blood loss Clotting stops continued or significant loss of blood from a wound.
Platelets
- Platelets These are fragments of cells that are involved in blood clotting and in forming scabs.
Sealing the wound
- Sealing the wound A scab forms an insoluble patch over the wound that prevents the entry of microorganisms.
Reducing infection
- Reducing infection Keeping bacteria and other pathogens out lowers the chance that the wound becomes infected.
Part 2 of 5How a Clot Forms
A series of reactions takes place in the blood plasma after the skin is broken.
1
The skin is broken and platelets arrive at the wound to help stop the bleeding.
2
Platelets release chemicals that start a series of reactions in the plasma.
3
These chemicals cause the soluble protein fibrinogen to be converted into insoluble fibrin.
4
Fibrin forms an insoluble mesh of threads across the wound.
5
Red blood cells are trapped in the mesh, producing a clot that blocks the leak.
Part 3 of 5From Clot to Scab
From Clot to Scab
Drying
- Drying The clot eventually dries out and hardens to become a scab.
Protection
- Protection The scab acts as a barrier that protects the wound from bacteria while repair takes place.
Healing
- Healing The scab stays in place until new skin has grown underneath, sealing the skin again.
Soluble to insoluble
- Soluble to insoluble Fibrinogen is soluble in plasma, whereas fibrin is insoluble, which allows a solid mesh to form.
| Substance | Solubility | Role |
|---|---|---|
| Fibrinogen | Soluble | Inactive form present in plasma |
| Fibrin | Insoluble | Forms the mesh of the clot |
| Platelets | Cell fragments | Release chemicals that start clotting |
Part 4 of 5Linking Clotting to Other Topics
Plasma
- Plasma Fibrinogen is carried dissolved in blood plasma, which also carries other proteins and dissolved substances.
Red blood cells
- Red blood cells These cells carry oxygen, and they are trapped within the fibrin mesh rather than doing the clotting.
Immune defence
- Immune defence Phagocytes and lymphocytes protect against any pathogens that do get past the barrier.
Clotting disorders
- Clotting disorders If blood clots too slowly a minor wound can bleed for a long time, and clots in the wrong place can block vessels.
Part 5 of 5Exam Checklist & Tips
9.1.17 – Key Points for the Exam
- Platelet A cell fragment in blood that helps form clots.
- Fibrinogen A soluble protein in blood plasma that is converted to fibrin.
- Fibrin An insoluble protein that forms a mesh to trap blood cells in a clot.
- Scab A dried clot that protects a wound while the skin repairs.
Common Mistakes
- Saying platelets are whole cells; they are fragments of cells.
- Writing that fibrin is converted into fibrinogen; fibrinogen is converted into fibrin.
- Forgetting to state that fibrin is insoluble and fibrinogen is soluble.
- Saying the clot is made of white blood cells; the mesh traps red blood cells.
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