If a serum specimen is diluted 1:2 with buffer beginning in tube 2 and serially rediluted 1:2 in each of five subsequent test tubes,what is the concentration of serum in tube 5?

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Quizplus · Accepted Answer

If a serum specimen is diluted 1:2 with buffer.A series of five tubes are prepared,in which each succeeding tube is rediluted 1:2.This is accomplished by placing 1 mL of diluent into each of four tubes (tubes 2 to 5).Tube 1 contains 1 mL of undiluted serum.Tube 2 contains 1 mL of undiluted serum plus 1 mL of diluent,resulting in a 1:2 dilution of serum.A 1-mL portion of the 1:2 dilution of serum is placed in tube 3,resulting in a 1:4 dilution of serum (1/2× 1/2 = 1/4).A 1-mL portion of the 1:4 dilution from tube 3 is placed in tube 4,resulting in a 1:8 dilution (1/4× 1/2 = 1/8).Finally,1 mL of the 1:8 dilution from tube 4 is added to tube 5,resulting in a 1:16 dilution (1/8× 1/2 = 1/6).
 The concentration of serum in terms of milliliters in each tube is calculated by multiplying the previous concentration (mL)by the succeeding dilution.In this example,tube 1 contains 1 mL of serum,tube 2 contains 1 mL× 1/2 = 0.5 mL of serum,and tubes 3 to 5 contain 0.25,0.125,and 0.06 mL of serum,respectively.

If a Serum Specimen Is Diluted 1:2 with Buffer Beginning