DNA STRUCTURE, REPLICATION AND RNA SYNTHESIS

DNA Structure, Replication and RNA Synthesis



DNA Structure, Replication and RNA Synthesis

DNA

Cells understand' how to how to produce ATP, how to construct cilia and centrioles, how to make membranes and enzymes. A program, or code, in living cells must be able to duplicate itself quickly and accurately and must also have a means of being decoded and put into effect.

The Genetic Code

Biologists call the program of the cell the genetic code. The work genetic refers to anything that relates to heredity. The genetic code is the way in which cells store program that they seem to pass from one generation to another.

The Transforming Factor

DNA is the nucleic unpleasant that stores and conveys the genetic information from one generation of an organism to the next. DNA carries the genetic code.

Bacteriophages

Some viruses are known as bacteriophages which mean bacteria eaters. Bacteriophages are composed of a DNA core and a protein coat. They attach themselves to the surface of a bacterium and then inject a material into the bacterium. Once inside the bacterium, the injected material begins to reproduce, making may copies of the bacteriophage. Soon the bacterium bursts, and several hundred bacteriophages are released to infect other cells. Because the material injected into the bacterium produces new bacteriophages, it must contain the genetic code.

The Structure of DNA

DNA is a polymer formed from units called nucleotides. Each nucleotide is a molecule makes up of three basic parts: a 5-carbon sugar called deoxyribose, a phosphate group, and a nitrogenous, or nitrogen-containing, base. DNA comprises four nitrogenous bases. Two of the nitrogenous bases, adenine and guanine, belonging to a group of compounds known as purines. The residual two, cytosine and thymine, are renowned as pyrimidines. Individual nucleotides are connected together to pattern a long chain.

"The DNA backbone is actually a great deal longer than the chromosome but is firmly coiled up within it. This cramming is now renowned to be founded on minute particles of protein known as nucleosomes, just evident under the most mighty electron microscope. The DNA is wound round each nucleosome in succession to form a beaded structure. The structure is then farther bent so that the beads aide in regular coils. Thus, the DNA has a coiled-coil configuration, like the filament of an electric powered powered lightweightweight bulb (William, 165).

After the discoveries of Watson and Crick, the inquiry that stayed was how the DNA directs the formation of proteins, mixtures central to all the methods of life. Proteins are not only the major components of most cell organisations; they furthermore command virtually all the chemical reactions that happen in dwelling matter. The ability of a protein to proceed as part of a structure, or as an enzyme influencing the rate of a specific chemical reaction, counts on its molecular shape. This form, in turn, depends on its composition. Every protein is made up of one or more components called polypeptides, and each polypeptide is a string of links of ...