Why Form 8815 Restrictions 2024-2025

When scientists began studying the way that bacterial cells protect themselves from different types of viral agents, they realized that inside bacterial cells are these special digestive proteins known as restriction enzymes or restriction nucleases. What these restriction enzymes do is they are able to cut or cleave the viral DNA molecule into many different pieces, thereby destroying and deactivating that viral DNA. One way that bacterial cells protect themselves from bacteria phages is by using these restriction enzymes. Now, because there are many different possibilities that a DNA sequence can consist of, we have many different types of restriction enzymes that exist in nature. Each of these restriction enzymes basically cleaves along a DNA molecule at a specific location on that double-stranded DNA molecule. In our study of these restriction enzymes, we realized that many of these enzymes actually cut at palindromic sequences along that double-stranded DNA molecule. To see what we mean by a palindromic sequence of DNA, let's take a look at the following diagram. Suppose we have a palindromic section of our double-stranded DNA. In any double-stranded DNA molecule, we have two single strands that run anti-parallel with respect to one another. The blue strand begins at the 5' end and ends at the 3' end, while the green strand begins at the 3' end and ends at the 5' end. We also have base pairing between the two single strands, with adenine pairing with thymine, and guanine pairing with cytosine. A palindromic sequence of DNA means that if we read these bases going in one direction, it will be the same as if we read them going in the opposite direction. For example, along the blue single strand, we have AAGCTT, and along the green strand, we also have AAGCTT. This is what we mean by...