Final answer:
To determine DNA concentration in a cuvette, one typically uses a spectrophotometer to measure absorbance at 260 nm. The concentration is then calculated using a known conversion factor based on the molar extinction coefficient for DNA.
Step-by-step explanation:
To determine how much DNA was in each microliter of the sample placed into the cuvette, we need to understand how DNA concentration measurements are typically performed in a laboratory setting. One common method involves using a UV/vis spectrophotometer and a standard quartz cuvette to measure the absorbance of the DNA sample at a wavelength of 260 nm. This absorbance can then be converted into a concentration using a conversion factor (often around 0.020 ng/mL for double-stranded DNA), which is based on the known molar extinction coefficient for double-stranded DNA.
For example, if one had an original DNA concentration that resulted in an absorbance of 0.326 when diluted with water in a ratio of 50 microliters of DNA solution to 950 microliters of water, this implies a 20-fold dilution (since the final volume is 1000 microliters, or 1 mL). Using the conversion factor, one can calculate the concentration of DNA in the original sample. If the DNA sample was prepared from a 0.5 µg/µl stock solution, then knowing the volume used, one can determine the amount of DNA per microliter in the cuvette directly.