QUANTITY | Length | Area | Volume | Mass | Density |
NAME/DEFINITION | Meter | Meter Squared | Meter Cubed | Kilogram | Mass per Unit Volume |
SYMBOL OF UNIT | m | m^{2} | m^{3} | kg | kg/m^{3} |
PREFIX | kilo | centi | mili | micro | nano |
SYMBOL | k | c | m | μ | n |
POWER OF 10 | 10^{3} | 10^{-2} | 10^{-3} | 10^{-6} | 10^{-9} |
Due to the nature of the research and materials, small units are used in biotechnology. Some procedure indicates that you are to obtain 0.0500 mL of cultured cells suspended in buffer. Then add 75.0 μL of Lysozyme sulution (concentration 100 μg/mL) and 50.0 μL RNase A (concentration 500 μg/mL).
Compute (a) the total volume of the solution in liters, (b) the number of grams of Lysozyme and RNase A added (c) the mass of the entire solution in grams if its density is 1050 kg/m^{3}. volume of cells + buffer = 0.0500 mL X [1 L/10^{3} mL] = 0.0500 X 10^{-3} L volume of Lysozyme solution = 75.0 μL X [1 L/10^{6} μL] = 75.0 X 10^{-6} L volume of RNase A solution = 50.0 μL X [1 L/10^{6} μL] = 50.0 X 10^{-6} L Total volume = [0.0500 X 10^{-3} + 75.0 X 10 10^{-6} + 50.0 X 10^{-6}] L = 1.75 X 10^{-4} L For the mass of Lysozyme, the units of density should match the units of volume. mL --> L = # of mL X 10^{-3} μg --> g = # of μg X 10^{-6} 100 μg/mL --> 100 [g X 10^{-6}]/[L X 10^{-3}] = 0.100 g/L mass of Lysozyme = 75.0 X 10^{-6} L X [.100 g/L] = 7.50 X 10^{-6} g mass of RNase A = 50.0 X 10^{-6} L X [.500 g/L] = 25.0 X 10^{-6} g For the mass of solution the units density should match the units of volume. Density is often reported in g/mL for liquids and g/cm^{3} for solids. The two expressions are equivalent, Some conversion factors to use at the present time are: m^{3} --> L = # of m^{3} X 10^{3} L --> mL = # of L X 10^{3} m^{3} --> mL or cm^{3} = # of m^{3} X 10^{6} kg --> g = # of kg X 10^{3} To convert 1050 kg/m^{3} to its g/cm^{3} equivalent, 1050 kg = 1050 X 10^{3} g 1.0 m^{3} = 1.0 X 10^{6} cm^{3} 1050 kg/m^{3} --> 1050 [g X 10^{3}]/[cm^{3} X 10^{6}] = 1.050 g/cm^{3} Volume of solution = 1.75 X 10^{-4} L X [10^{3}mL/ L] = 0.175 mL or cm^{3} mass of solution = Volume X density = 0.175 cm^{3} X 1.050 g/cm^{3} = 0.18375 ~ 0.184 g |