my namemy teacher,the hourJune 5, 1996Genetics is the study of how physical, biochemical, and behavioral traits are transmitted from parents to their offspring. The science of genetics started in 1900, when the work of Gregor Mendel was discovered. Mendel described the inheritence patterns of garden peas.
He suggested after researching his pea-plant experiment that each parent has pairs of units but contributes only one unit for to each pair of its offspring. These units were later given the name genes. Every cell comes from a division of a cell that is already existing. For example, all cells that make up a human being are derived from divisions of a single cell, called the zygote. Chromosomes usually occur in pairs and are various sized and shapes. The members of each pair ar called homologues.
The human body contains 23 pairs of chromosomes, while the fruit fly contains four pairs. Every chromosome in a cell is known to contain many genes and each gene is located at a particular site, or locus, on the chromosome. Theodore Oswald Avery a Canadian-born Physician nad bacteriologist who is known for wondrous discoveries in the genetic field. He earned his medical degree at Columbia University’s College of Physicians and Surgeons.
He was the first to show that the agent responsible for transferring genetic information was not aprotein , as what was then thought in his time, but the nucleic acid DNA. Avery and his co-workers extracted a substance from a type of bacterium with a smooth surfac and introduced the substance into a rough surfaced type of bacterium. When the rough surfaced bacteria was transformed into the smooth-surfaced type, he knew the substance that had been extracted contained the gene that coded ford the smooth surface. He and his team purified theis substance and found it was pure DNA. Avery published the results of this research in 1944. The genetic material is deoxyribonucleic acid, or simply put, DNA.
DNA is a molecule that forms a the “backbone of a chromosome. Since the continuous molecule is is long and thin the genes are a part of that molecule. Because the DNA is a chain of minute subunits called nucleotide bases, each gene includes many bases. In the chain four different bases exist- adenine, cytosine, guanine, and thymine. Their order in each particular gene determines its properties.
Genes puat out their effects through the molecules that they produce. The immediate products of a gene are molecules of ribonucleic acid, (RNA). These are virtually the same as DNA except that RNA has uracil as a base instead of thymine. RNA molecules of some genes play a certain role in the metabolism of the organism, but most of them are used to make protein. Proteins are chains of subunits called amino acids. The sequenceof these amino acids in a protein dictates whether or not it will become part of the structure of the organism, or whether it will become an enzymeefor promoting a certain chemical reaction.
Genetic EngineeringGenetic Engineering is the method of changing the inherited characteristics of an organism in a predetermined way by altering its genetic material. This is often done to cause microorganisms, like a bacteria or a virus, or to synthesize increased yields of compounds, to form entirely new compounds to form completely new compounds. This process is alsoused to adapt to different environments. Another is called recombinant DNAtechnologym including gene therapy which is the supply of a functioal gene to a person with a genetic disorder or with other diseases such as AIDS or cancer. Genetic Engineering involves the process of manipulating DNA. Restriction enzymes are very important tools in this process.
The restriction enzymes are produced y various species of bacteria, and they can recognize a particular sequence of the chain of chemical units called nucleotide bases, which make up the DNA molecule and cut the DNA at that location. Small bits of DNA generated in this way can be joined using other enzymes called ligases. Restriction enzymes and ligases therefore allow the specificcutting and reassembling of picies of DNA. Vectors are also important in the manipulation of DNA. These vectors are pieces of DNA that can self-replicate by themselves the DNA, making this .
