1/7/2024 0 Comments Amino acid sequence chart![]() The code must be a three base code (or triplet code), because it is the simplest code that allows for the 20 known amino acids: 4 X 4 X 4 = 64. With the same logic, Gamow surmised that the code could not be represented by a combination of two nucleotides, because 4x4 is 16 and there are 20 amino acids. If an amino acid was based on a single nucleotide, then there would only be four amino acids. Since there are only four unique nucleotides in DNA and 20 amino acids, a combination of base pairs was required to code for the amino acids. His reasoning was based on the observation that there are 20 amino acids. He suggested that each code word contains three bases. What is the genetic code? What are the rules that specify the relationship between the sequence of nucleotides in DNA and the sequences of amino acids in a protein? George Gamow suggested a code based on logic. The next challenge was understand how the sequence of bases in a strand of messenger RNA code for the sequence of amino acids in a protein. ![]() Once biologists understood the dogma, they understood the general pattern of information flow in the cell. RNA editing, in which an RNA sequence is altered by a complex of proteins and a "guide RNA", could also be considered an RNA-to-RNA transfer. The enzymes that copy RNA to new RNA, called RNA-dependent RNA polymerases, are also found in many eukaryotes where they are involved in RNA silencing. RNA replication is the copying of one RNA to another. DNA codes for RNA and that RNA codes proteins. But even though there are exception to the dogma, the central dogma of molecular biology encompasses The most important flow of information for life. So in this way, the information flow would be from RNA to DNA. When these viruses infect a cell, the viral RNA synthesizes DNA. Some viruses for example have genes composed of DNA. The other major exception to this dogma, the information flow is reversed. So the information flow in this case would be simply DNA to RNA. And DNA directly codes for these RNA molecules. Some are also involved in protein synthesis (like transfer RNA). Messenger RNA is just one of seven major different types of RNA.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |