Explanation: E.coli isolated from the gram-negative bacterium Escherichia coli. A recognition sequence is the one where an enzyme cleaves.

Explanation: Many restriction endonucleases like PvuII, AluI, HaeIII simply cleave the double stranded DNA producing bunt or flush ends.

Explanation: PvuII produces blunt ends whereas all others produce sticky ends. Some endonucleases cleave the DNA strand in a staggered way usually by two or four nucleotides, so that the resulting DNA fragments have short single-stranded overhangs at each end.

Explanation: Most endonuclease function at pH 7.4, but different enzymes vary in their requirements for ionic strength and concentration. It is advisable to add a reducing agent like DTT which stabilizes the enzyme and prevents its deactivation. Before adding the enzyme, solution containing DNA must be adjusted to provide the correct conditions for maximum enzyme activity.

Explanation: Most endonucleases work best at 37 degrees, TaqI enzyme from Thermus Aquaticus has a high working temperature like Taq DNA polymerase.

Explanation: Whether or not a DNA molecule is cut can be determined by viscosity examination. Larger DNA molecules result in more viscous solutions, DNA cleavage is associated with a decrease in viscosity.

Explanation: Gel electrophoresis is a technique by which the sizes of fragmented DNA molecules can be measured against a molecular weight ladder of standard weights.

Explanation: Shape and charge-to-mass ratio of nearly all DNA molecules is same and therefore to separate them gel electrophoresis is done in place of conventional electrophoresis.

Explanation: A very thin (0.3mm) polyacrylamide gel with extremely small pores can be used to distinguish small DNA molecules, can distinguish between molecules differing in length by just a single nucleotide.

Explanation: Cutting with two different enzymes and at two different sites is done to create a restriction map of the genome of an organism.

Explanation: To perform partial digestion either incubation period is shortened or incubation is done at a low temperature at around 4 degrees which limits the activity of the enzyme.

Explanation: As well as the standard fragments of total digestion, partially digested fragments are also seen as additional bands giving overall complexity.

Explanation: OFAGE is an advanced gel electrophoresis technique used for the separation of DNA molecules of over 50 kb in length.

Explanation: The eukaryotic genome is large and simple techniques like gel electrophoresis cannot distinguish the DNA molecules ranging in several thousand basepairs.

Explanation: Field Inversion Gel Electrophoresis is a modification of OFAGE in which parallel alternating pairs of electrodes are placed.