Case Of The Crown Jewels Template (Page 23 of 28) in pdf

Case Of The Crown Jewels Template Page 23

ESTRICTION

NZYME

ORKSHEET

AME

Restriction enzymes are important tools for the researcher. Since each DNA molecule is unique, it will

produce unique fragment sizes when cut by a restriction enzyme. These fragments can be used to identify

DNA molecules.

The DNA fragments need to be separated in order to be compared. The fragments are sorted by passing

them through a gel. The gel acts like a screen, allowing small pieces of DNA to pass through more easily

than large pieces, much like sifting rocks out of dirt. Electricity is used to move the DNA through the gel

matrix. Since DNA has a negative charge when it is placed in an electric field, it migrates toward the

positive pole.

FIGURE 1: Gel Electrophoresis sorting fragments of DNA by size

Results after sorting by size

Negative

Electrode (-)

DNA

Positive

Electrode (+)

The process of sorting DNA fragments by size using a gel and electricity is called gel electrophoresis.

EcoR

Hind

FIGURE 2: DNA Strand with specific

I and

III sites

EcoRI

HindIII

EcoRI

cut site

bp - base pairs

2300 bp

4000 bp

3000 bp

5000 bp

R e s t r i c t i o n E n z y m e W o r k s h e e t 2

P a g e 21

Case Of The Crown Jewels Template Page 23