Lab 8 Flashcards
What is the charge of DNA? + or -?
Negative due to the phosphate backbone
What is the gel made from? what does it “look like” at a molecular level?
the gel is made up of agarose, a polysaccharide extracted from the cell wall of algae. The gel looks like a matrix which the DNA molecule has to find its way through.
What is the ‘loading die’ used for? what does it contain? what are the functions of the individual ingredients.
sucrose loading die is used. The sucrose makes the sample more dense than the surrounding buffer; thus, keeping the sample in the well. The die made of bromophenol blue helps in loading the sample into the blue. The dye also runs at a known speed which is about the same speed as a 500bp DNA fragment and lets us know when to stop the electrical current.
Which DNA fragments will travel the farthest during gel electrophoresis?
Short ones as they can find their way through the matrix easier.
What is a ‘DNA’ ladder?
ran beside the samples as it contains linear pieces of DNA of known lengths that can be used to compare to sample DNA to determine their size.
What is Ethidium bromide dye used for?
indicating the DNA you want to detect
Why do we have to visualize the DNA fragments in the gel using UV light?
Ethidium bromide inserts between base pairs in the DNA and fluoresces under UV light. Thus allows us to visualize the DNA fragments.
What do bands on the gel constitute?
thousands of microscopic fragments of a given size.
