Restriction Enzymes
The position at which the desired gene is inserted into the vector genome is greatly influenced by the restriction enzymes utilized in recombinant DNA technology. E-coli was the first restriction enzyme to be isolated in 1963 from the development of bacteriophage in the laboratory.
This enzyme was able to cleave DNA but not the precise side of DNA cleavage. In 1970 Hemeltan Smith and his co-worker isolate the restriction enzyme activity from the bacterium Haemophilus influenzae strain Rd, showing it was able to cleave DNA at a specific site that is referred to as Hind II recognized six double Standard DNA Sequence that is GI, PY, PU, AC.
In addition to Hind II, there are approximately 900 restriction enzymes known, each of which recognizes a different recognition sequence. These enzymes were isolated from over 230 bacterial strains.
Restriction enzymes are part of a larger class of enzymes referred to as nucleases. Nucleases degrade the DNA Molecules by breaking the phosphodiesterase bond that is one molecule nucleotide the next in the DNA strength. Exonucleases and endonucleases are two different types of nucleases. Exonucleases remove nucleotides one at a time from the ends of the DNA whereas, endonucleases comprised cuts at specific positions within the DNA. The DNA is cut at specified locations by restriction endonucleases, which are sequence-specific and typically palindrome sequences.
For example, E-coli enzyme Exonucleases degrade just one end of the double standard molecules and leave single standard DNA as a product. Sequences read identically in a 5′ à 3′ direction on both strands. This is also accurate when measured from 3′ to 5′..
5′ —— GAATTC —— 3′
3′ —— CTTAAG —— 5′
NCERT Notes Biology Class 12 Chapter 9 Biotechnology: Principles and Processes
NCERT CBSE Class 12th Science Notes Chapter 9 Biotechnology: Principles and Processes: Biotechnology Principles and Processes is an important part of Class 12 Science Notes for quick revision. They will benefit from having challenging study material to use in preparing for the exam. Students can get CBSE Class 12th Science Notes Chapter 9 Biotechnology: Principles and Processes, Biotechnology, the principle of biotechnology, Recombinant DNA Technology, Separation and Isolation of DNA Fragments, Tools of Recombinant DNA Technology.
The branch of biology known as biotechnology is where technology is used to improve human health. Biotechnology is the production, development, and modification of useful products to satisfy the needs of all living things.
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