## artisunder 2 years ago What percentage gel should be used if you want to separate DNA fragments that are 25,000 bp , 21,000 bp, 10,000 bp and 6,000 bp?

1. Reaper534

hvent learnd it :(

2. karatechopper

Sorry, I haven't learnt this either.

3. Frostbite

Hmmm what kind of gel? almost guessing agarose?

4. Frostbite

If we don't have this factor it can be hard to know becuase the driving force of the molecule or DNA is given by: $f=6 \pi \eta r$ Here f is the driving force, η is the viscosity of the medium and r is the radius of a sphere.

5. Frostbite

But if using a agarose gel I would say about 0,5 % agarose, that should cover 1k to 30k.

6. artisunder

oh wow, thank you! thank you so much!!!!

7. Frostbite

and standard plate btw. ;)

8. ontour

@Frostbite dude continue helping her :D please! shes in ap bio XD

9. Frostbite

Not sure I follow?

10. ontour

Oh. She's Advanced Placement Biology and she needs help haha.

11. artisunder

I'm in ap bio and i don't get this lab report at all haha

12. Frostbite

Well this is college bio, so I wonder if you don't have any tables to look in, I only found it, becuase I had a old table from a prof of mine. The eqautions however is stright on ;)

13. ontour

ARTI ASK THE NEXT QUESTION CHILD

14. artisunder

@Frostbite could you help me with some other questions? :)

15. Frostbite

Maybe, I'll give it a shot.

16. artisunder

you perform a restiction digest that should yield 1400 bp, 1080 bp, and 400 bp fragments. You check the restiction digest by running it on a gel that is 1.5 %, the correct percentage. but you're in a rush and only partially run the gel you also forget to load the marker

17. artisunder

when you stain the gel you only see three bands in the lane you loaded. The second band from the well is more intense than thr others and looks like a doublet. which 2 fragements make up the double? why? what could you do to further separate the fragemnts to verify this?

18. Frostbite

19. artisunder

oh, okay thank you though! how about this one ----> if you want to run gel electrophoresis at 100 v for two hours instead of one (which is how long it should take) what should you do?

20. Frostbite

Hmmm an increase in running time will allow the bands to separate even more... wich you ofcuase need to take into account if you make a aproximation. Beside from that, I most again say I'm not sure.

21. Frostbite

Might also need to adjust some equations if you have some formular that have bps as a function of length of bands travel.

22. artisunder

i was thinking that you could rin it at half the voltage (50 v)

23. Frostbite

Oh, then i misunderstod well depends if voltage and time is porportional ;)

24. artisunder

haha i don't really know. I'm just going to out that down and hope for the best!