Basic calculation - But i am confused - (Jun/03/2015 )

Hello,

 

I know this is a basic calculation but i am confused. Example:

 

Protocol says take 1 microgram (ug) of your DNA/RNA sample. I have DNA/RNA as 50 ng/ul. So, how do i convert it to get it to microgram and how much of the DNA/RNA sample should i pipette to achieve the 1 microgram?

 

Thanks.

1000/50=

bob1 on Wed Jun 3 18:15:59 2015 said:

1000/50=

its 20.

Use units!

X ul = (1 ug)/(50 ng/ul) = (1000 ng)/(50 ng/ul)

Notice that the ul on both sides cancel. Notice that the ng above and below cancel.

X = 1000/50 = 20

 

So, you need 20 ul

 

If you don't get the correct units, your answer is wrong.

phage434 on Wed Jun 3 21:08:04 2015 said:

Use units!

X ul = (1 ug)/(50 ng/ul) = (1000 ng)/(50 ng/ul)

Notice that the ul on both sides cancel. Notice that the ng above and below cancel.

X = 1000/50 = 20

 

So, you need 20 ul

 

If you don't get the correct units, your answer is wrong.

Thanks for the detailed explaination.

 

So, if i have to take 1 pg then it should be:

x ul = (1pg)/(24ng/ul) = (1 pg)/(50000 pg/ul)

x = 1/50000 = 0.00002 ul

 

Am i correct?

Looks OK.

 

THe other option is to remember the prefix of the unit... I bet you know how much a kilogram is in terms of grams... so milli is 10^-3; micro, 10^-6; nano, 10^-9; pico, 10^-12; femto, 10^-15, most people don't work with units below this so you can forget about atto, zepto and yocto.

 

As you can see each one is 1000 times smaller than the unit before it, so conversion is easy.

Mad Researcher on Thu Jun 4 15:02:25 2015 said:

 

phage434 on Wed Jun 3 21:08:04 2015 said:

Use units!

X ul = (1 ug)/(50 ng/ul) = (1000 ng)/(50 ng/ul)

Notice that the ul on both sides cancel. Notice that the ng above and below cancel.

X = 1000/50 = 20

 

So, you need 20 ul

 

If you don't get the correct units, your answer is wrong.

Thanks for the detailed explaination.

 

So, if i have to take 1 pg then it should be:

x ul = (1pg)/(24ng/ul) = (1 pg)/(50000 pg/ul)

x = 1/50000 = 0.00002 ul

 

Am i correct?

 

is it 24 or 50ng/ul?

mdfenko on Fri Jun 5 11:44:57 2015 said:

 

Mad Researcher on Thu Jun 4 15:02:25 2015 said:

 

phage434 on Wed Jun 3 21:08:04 2015 said:

Use units!

X ul = (1 ug)/(50 ng/ul) = (1000 ng)/(50 ng/ul)

Notice that the ul on both sides cancel. Notice that the ng above and below cancel.

X = 1000/50 = 20

 

So, you need 20 ul

 

If you don't get the correct units, your answer is wrong.

Thanks for the detailed explaination.

 

So, if i have to take 1 pg then it should be:

x ul = (1pg)/(24ng/ul) = (1 pg)/(50000 pg/ul)

x = 1/50000 = 0.00002 ul

 

Am i correct?

 

is it 24 or 50ng/ul?

 

It should be 50 ng/ul.
By mistake i calculated it for 24 ng/ul

Thanks for pointing that out.

Mad Researcher on Fri Jun 5 11:47:37 2015 said:

 

mdfenko on Fri Jun 5 11:44:57 2015 said:

is it 24 or 50ng/ul?

 

It should be 50 ng/ul.
By mistake i calculated it for 24 ng/ul

Thanks for pointing that out.

 

you wrote 24 but calculated 50

mdfenko on Fri Jun 5 12:14:29 2015 said:

 

Mad Researcher on Fri Jun 5 11:47:37 2015 said:

 

mdfenko on Fri Jun 5 11:44:57 2015 said:

is it 24 or 50ng/ul?

 

It should be 50 ng/ul.
By mistake i calculated it for 24 ng/ul

Thanks for pointing that out.

 

you wrote 24 but calculated 50

 

Oops thanks for correcting me :)