You have three BSA working solutions: 5ug/ul, 0.5 ug/ul, and 0.05 ug/ul. Each tube contains 500 ul of solution. How much of which concentration(s) would you pipet into three different centrifuge tubes so you end up with 20 ug, 2 ug, and 0.2 ug of BSA in each tube

I would pipet 4 μl of each BSA work solution

Explanation:

To calculate the mass (in μg), we have to multiply the concentration C (in μg/ul) by the volume V (in μl):

C(μg/ul) x V( μl) = mass (μg)

We found the required volume for each solution, as follows:

5 μg/μl x V₁ = 20 μg ⇒ V₁ = 20 μg/(5 μg/μl ) = 4 μl

0.5 μg/μl x V₂ = 2 μg ⇒ V₂ = 2 μg/(0.5 μg/μl) = 4 μl

0.05 μg/μl x V₃ = 0.2 μg ⇒ V₃= 0.2 μg/(0.05 μg/μl) = 4 μl

Therefore, we need to pipet 4 μl of the solutions of concentrations 5μg/μl, 0.5 μg/μl, and 0.05 μg/μl to obtain the masses 20 μg, 2 μg, and 0.2 μg, respectively.

the tides are influenced by both the moon and the sun, it's easy to see that when the sun lines up with the moon and the earth, as during a new moon or full moon, the tidal effect is increased. these are known as spring tides, named not for the season, but for the fact that the water "springs" higher than normal. on the other hand, if the sun and the moon are 90 degrees apart in relation to an observer on earth as during the first quarter moon or third quarter moon, then high tides are not as high as they normally would be. this is because despite its greater distance, the sun's mass allows it to exert enough gravitational force on the oceans that it can negate some of the effects of the moon's pull. this phenomenon of lower high tides is called a neap tide. if you need more information on this topic visit moonconnection.com.