Nuclease: Definition, Function & Activity

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  • 0:02 Nuclease: Definition
  • 0:58 Nuclease Function
  • 2:34 GMOs
  • 3:33 Lesson Summary
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Lesson Transcript
Instructor: Jeremy Battista
In biology, we encounter many chemicals with the suffix 'ase' attached to them. This is fairly indicative of an enzyme that will break chemical bonds. In this lesson, we will look at nucleases and what bonds they break.

Nuclease: Defintion

The suffix ase generally refers to enzymes. In this case, nuclease (pronounced nuk-lee-aize) is an enzyme that is responsible for breaking the bonds between nucleotides in nucleic acids. nucleotides, are the small subunits that make up large nucleic acids, such as DNA and RNA.

There are four kinds of nucleotides found in DNA and RNA: adenine, thymine, cytosine, and guanine, with uracil replacing thymine in RNA. Each nucleotide will match up with another particular nucleotide, coming together to form a DNA or RNA strand. For example, when forming the DNA 'ladder', adenine will line up across from thymine, and cytosine will line up across from guanine. In RNA, uracil matches up with adenine.

Nucleases can be used to split RNA or DNA for various reasons, like replication, recombination, and repair of damaged DNA sequences.

Nuclease Function

A nuclease works by scanning a sequence of DNA or RNA, looking for a specific sequence. If it encounters that sequence, it will attach to it and cut out that particular sequence. Where the sequence is encountered will determine which nuclease will cut the sequence.

Nucleases can be broken down into two subunits, called endonucleases and exonucleases. Exonucleases cut off the end of a nucleotide sequence, one by one. Endonucleases will cut out certain nucleotide sequences right in the middle of a nucleic acid. It can chop the DNA sequence in half or just remove certain parts of it. There is also another branch of endonucleases called restriction nucleases. These are used, as the name suggests, to restrict certain sequences of DNA or RNA. These can be used to destroy viruses, since the nuclease can detect their sequences and begin to cut them up, thus 'killing' the viruses.

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