Central dogma of molecular genetics

What Crick called the "central dogma of molecular genetics" says that the function of DNA is to store information and pass it on to RNA. The function of... 

As the field of molecular genetics grew, the DNA molecule became the focus of many research efforts. Francis Crick and George Gamov developed the sequence hypothesis to explain how DNA makes protein. They stated that the DNA sequence specifies the amino acid sequence of a protein and postulated the central dogma of molecular genetics the flow of genetic information is a one-way road, it always takes the direction from DNA to RNA to protein [16]. In the same year, 1957, Mathew Meselson and Frank Stahl demonstrated the replication mechanism of DNA [17]. In 1958, DNA polymerase became the first enzyme used to make DNA in a test tube. 

The structure of DNA/RNA enabled Crick to formulate the central dogma of molecular genetics. By this dogma, three fundamental processes take place in the transfer of genetic information. Replication is the process by which identical copies of DNA are made so that information can be preserved and transferred from generation to generation. 

The central dogma of molecular genetics The central dogma was based upon the findings of Watson and Crick and states that the flow of information is essentially in one direction from DNA to protein. Three major steps can be defined in the process replication, transcription and translation of genetic material, as shown in Fig. 5.A9. 

Since then some progress has been made in this direction (completely independently of Ya.B. ) in violation of the central dogma of molecular genetics, influence of transport RNA on DNA was discovered. It is possible that the ideas of how reacting substances influence enzymes will prove significant in the study of the prebiological stage of evolution. 

The central dogma of molecular genetics describes how hereditary information is transmitted and used to synthesize proteins. The main features of this theory are shown in Fig. 21-7. DNA is the storage form of hereditary information. The hereditary information is the sequence of nucleotide residues in DNA which corresponds to a specific sequence of amino acid residues in a polypeptide. Replication is the process of copying DNA during cell division. Transcription is the synthesis of RNA from DNA, the first step in the transmission of hereditary information. Three types of RNA are produced, ribosomal RNA (rRNA), messenger RNA mRNA), and transfer RNA (tRNA). rRNA, mRNA, and tRNA participate in the process of translation—the synthesis of protein. 

Fig. 21-7 Basic features of the central dogma of molecular genetics.

Soon after the Watson—Crick hypothesis was published, scientists began to extend it to yield what Crick called the central dogma of molecular genetics. This dogma stated that genetic information flows as follows ... 

What Crick called the "central dogma of molecular genetics" says that the function of DNA is to store information and pass it on to RNA. The function of RNA, in turn, is to read, decode, and use the information received from DNA to make proteins. This view is greatly oversimplified but is nevertheless a good place to start. Three fundamental processes take place. 

Figure 20.18 The central dogma of molecular biology a summary of processes involved inflow of genetic information from DNA to protein. The diagram is a summary of the biochemical processes involved in the flow of genetic information from DNA to protein via RNA intermediates. This concept had to be revised following the discovery of the enzyme, reverse transcriptase, which catalyses information transfer from RNA to DNA (see Chapter 18). It may have to be modified in the future since changes in the fatty acid composition of phospholipids in membranes can modily the properties of proteins, and possibly their functions, independent of the genetic information within the amino acid sequence of the protein (See Chapters 7, 11 and 14).

The central dogma of molecular biology describes how one form of biological information (an organism s genetic sequence) is processed in terms of DNA replication, RNA transcription, and protein synthesis. However, a related mystery is yet to be worked out in sufficient detail how is the information encoded in the DNA (i.e., genotypes) related to cellular functions (i.e., phenotypes) How do different signals tell different cells to synthesize different proteins ... 

The central dogma of molecular biology states that genetic information flows from genes, via RNA, to proteins. In this flow of information, messenger RNA (mRNA) is generated in a process called transcription and is subsequently processed to yield a mature transcript. The transcriptome is the combined set of aU transcripts present in a cell at a certain time, but it should be noted that mRNA is only a minor component of the entire... 

This concept has been referred to as the central dogma of molecular biology because it describes the flow of genetic information from DNA through RNA and eventually to proteins. 

The central dogma of molecular biology has traditionally posited that nucleic acids alone function as genetic determinants because these macromolecules can template their own replication. The prion or protein-only hypothesis expands the central dogma to include proteins as etiologic agents for disease transmission (Griffith, 1967 Prusiner 1982) and elements of inheritance for phenotypic traits (Wickner, 1994). Prions are unique proteins that can exist in more than one stable conformation, and at least one of these states can be transmitted to newly synthesized protein as a form of templated replication. Since each physical state is associated with a distinct phenotypic state, the trait becomes heritable. 

Figure 3.1 The Central Dogma of Molecular Biology. Black lines represent information transfers that occur frequently in cells. Blue indicates the exception of reverse transcription that occurs in some viruses, and RNA-directed RNA polymerase catalyzed RNA replication that also occurs in some plants and viruses only. Nucleic acids can be both stores and recipients of genetic information, whereas proteins are always recipients only of genetic information.

If DNA is the master copy (the ROM) of a cell s genetic program, its integrity must be preserved. One way the DNA is protected is because RNA acts as the working copy (the RAM). Chemically, RNA is very similar to DNA. Biochemically, the major difference is that RNA either acts as a component of the metabolic machinery or is a copy of the information for protein synthesis. The relationship between DNA and RNA is called the central dogma of molecular biology ... 

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