List the constituents of plasma and the functions of plasma proteins.

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College Answer

This question was generally well answered. The constituents of plasma include water, 
electrolytes, glucose, liver enzymes, urea, creatinine, uric acid, dissolved gases and proteins. 
Plasma does not contain any cells. The proteins in plasma are albumin, globulins and 
fibrinogen. The globulins include alpha 1 and 2 and beta globulins and gamma globulins. 
Examples of α1-Globulins are: α1-fetoprotein, α1-protease inhibitor and prothrombin. 
Examples of α2-Globulins include: ceruloplasmin, haptoglobin, α2-macroglobulin and 
thyroxin-binding globulin. Examples of β-Globulins are: C-reactive protein, β2-microglobulin 
and transferrin. Examples of δ-Globulins are the immunoglobulins , IgG, IgA, IgM, etc. There 
are many more other globulins including the coagulation factors, the complement system 
and lipoproteins. The functions of plasma proteins include oncotic pressure, 
transport/carrier function, role in acid base balance (buffering, CO2 transport) and 
proteolytic systems such as complement, kinins, coagulation and fibrinolysis. More 
functions include the immune response, enzyme activity eg pseudocholinesterase, 
metabolism i.e. plasma proteins can be broken down and contribute amino acids to the 
amino acid pool and a role in thermoregulation. Many answers were deficient in details on 
the plasma proteins and their functions. The question asked to “list” the constituents, so the 
level of detailrequired to score marks reflected this and should have been achievable in the 
allocated timeframe.