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GCSE Biology · key term
A small fragment of a cell in the blood that helps blood to clot at a wound.
Used by AQA, Edexcel and OCR
Specification 4.2.2.3 · Paper 1
A small fragment of a cell that helps blood to clot at a damaged blood vessel.
Revise: Blood CompositionRed blood cells, white blood cells and platelets are suspended in this plasma and carried through the blood vessels.
Specification 8.6 · Paper 2
A small cell fragment in blood that helps start clotting at a damaged blood vessel.
Revise: Blood ComponentsBlood carries materials around the body and helps protect it. It contains red blood cells, white blood cells and platelets suspended in plasma. These components have different structures because they do different jobs: carrying oxygen, defending against infection, transporting dissolved substances and limiting blood loss.
Specification B6.3j · Paper 2 (Foundation), Paper 4 (Higher)
A small cell fragment in blood that helps form a clot at a wound.
Revise: White blood cells and plateletsBlood contains white blood cells that help deal with pathogens and platelets that help seal the wound. Their structures suit these different defence jobs.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: PlateletsPlatelets are small fragments of cells carried in the blood plasma. Their function is to help form a blood clot at a wound. This limits blood loss and seals the damaged area, reducing the chance of pathogens entering the blood.
When identifying cells in a blood smear, use more than colour: red blood cells are numerous, small and lack a nucleus; white blood cells are larger and have a visible nucleus; platelets are much smaller fragments.
Do not describe plasma as a cell. It is the liquid part of blood in which blood cells and platelets are suspended.
Distinguish platelets from white blood cells: platelets cause clotting, whereas white blood cells defend the body against pathogens.
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