14 Questions
What is the primary function of a restriction enzyme in a bacterial cell?
To defend against bacterial viruses
Why are restriction enzymes indispensable tools of recombinant DNA technology?
Because they can manipulate fragments of DNA
What is the name 'restriction enzyme' derived from?
Their ability to restrict the number of strains of bacteriophage that can infect a bacterium
What is the recognition sequence of a restriction enzyme?
A short, specific sequence of nucleotide bases
What is the purpose of a bacteriophage infecting a bacterium?
To insert its DNA into the bacterial cell
Why do different bacterial species make different restriction enzymes?
Because they recognize different nucleotide sequences
What is the role of restriction enzymes in defending against bacteriophages?
To prevent replication of phage DNA
What is the substrate of a restriction enzyme?
DNA molecule
Why are restriction enzymes produced by bacteria?
To protect against viral infections
What is the result of a restriction enzyme cleaving foreign DNA?
The elimination of the foreign DNA
What determines the specificity of a restriction enzyme?
The sequence of nucleotide bases
What is the purpose of a restriction enzyme in the laboratory?
To manipulate DNA fragments
What is the distribution of recognition sites in a DNA molecule?
Randomly distributed throughout the DNA
What is the characteristic of a recognition sequence?
A specific sequence of nucleotide bases
Study Notes
Restriction Enzymes and Their Function
- Produced by bacteria to cleave DNA at specific sites along the molecule
- Used by bacteria to defend against bacterial viruses (bacteriophages) by preventing replication of phage DNA
- Recognize short, specific sequences of nucleotide bases (recognition sequences or recognition sites) randomly distributed throughout the DNA
- Cut DNA into many pieces, restricting the number of phage strains that can infect a bacterium
Mechanism of Action
- Restriction enzymes cleave foreign DNA, eliminating infecting organisms
- In the laboratory, they are used to manipulate fragments of DNA, including those containing genes
- Essential tools in recombinant DNA technology (genetic engineering)
Characteristics and Variation
- Different bacterial species produce restriction enzymes that recognize different nucleotide sequences
- Each restriction enzyme has its unique recognition sequence
Learn about restriction enzymes, proteins produced by bacteria that cleave DNA at specific sites, and their role in genetic engineering. Understand how they eliminate foreign DNA in bacterial cells and are used in laboratory DNA manipulation.
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