Question

Part I: Each statement below is false. Change the bolded word to make the statement true.

a) Restriction enzymes are used to make DNA circular.

b) Gel electrophoresis can tell you the sequence of a particular DNA fragment.

c) Fluorescence allows you to visualize bands of DNA on a gel.

d) DNA positively charged and is attracted to the negative electrode.

e) The speed at which DNA moves through a gel is directly related to its charge.

f) Larger fragments move fastest and furthest through the agarose gel.

g) When visualizing your gel, you can tell the size of the DNA fragments by the width.

h) Ethidium bromide acts as a buffer to conduct electricity and maintains pH.

Answer 1

a) Restriction enzymes are used to make DNA circular.

Restriction enzymes cut on the DNA if the DNA is circular restriction enzymes make it linear.

Restriction enzymes are used to make DNA linear.

b) Gel electrophoresis can tell you the sequence of a particular DNA fragment.

gel electrophoresis cannot give the sequence of the DNA fragments, but it can give size of DNA fragments.

Gel electrophoresis can tell you the size of a particular DNA fragment.

c) Fluorescence allows you to visualize bands of DNA on a gel.

Dyes which we use helps us to visualize bands of DNA on the gel, EtBr is one such dye.

DNA binding dyes allow you to visualize bands of DNA on a gel.

d) DNA positively charged and is attracted to the negative electrode.

DNA is negatively charged due to the presence of phosphate groups and it moves to positively charged electrode during electrophoresis.

DNA negatively charged and is attracted to the positive electrode.

e) The speed at which DNA moves through a gel is directly related to its charge.

all DNA molecules are negatively charged so the speed at which it moves through the gel depends on the size of the DNA.

The speed at which DNA moves through a gel is directly related to its size.

f) Larger fragments move fastest and furthest through the agarose gel.

larger DNA fragments move slowly and close through the agarose gel.

g) When visualizing your gel, you can tell the size of the DNA fragments by the width.

smaller DNA fragments move faster and larger fragments move slowly so it remains close to the wells in the gel so the position of bands on the gel with respect to the ladder, helps to identify its size.

When visualizing your gel, you can tell the size of the DNA fragments by the position.

h) Ethidium bromide acts as a buffer to conduct electricity and maintains pH

running bufffer conduct electricity and maintains pH, the common running buffer used in DNA gel electrophoresis are TAE and TBE.

running buffer (TAE or TBE) acts as a buffer to conduct electricity and maintains pH