Literary Physics

Syllabus dot drive Notes * process information from collateral sources to describe an example of hybridisation within a species and explain the endeavor of this hybridisation Hybridisation two genetically different strains of an organism argon crossed to produce manifestation with desirable characteristics. i. e. cross breeding cattle to produce better meat, which will benefit for human purpose Selective breeding of sheep to produce merino sheep which are hybrids produced by interbreeding other sheep varieties.Interbreeding other varieties of feed to produce the resultant hybrid corn that was hardy and produced large fruit. * describe the process of DNA counterpunch and explain its significance * DNA double helix unwinds * DNA unzips * Nucleotides are added to each single strandDNA replication ensures that the genetic information is maintained. * explain the relationship between proteins and polypeptides A protein is made up of ane or more polypeptides.A polypeptide is ma de up of a chain of many amino acids. * analyse information from secondary sources to outline the evidence that led to Beadle and Tatums adept gene one protein hypothesis and to explain why this was altered to the one gene one polypeptide hypothesis Beadle and Tatum concluded that for each defective enzyme there was one gene on one specific area of a chromosome that had been mutated by irradiation. This led to their one gene-one enzyme theory.The one gene one enzyme hypothesis changed to the one gene one protein hypothesis, once it was demonstrated that there are other proteins besides enzymes that are encoded by genes. Thomas Morgans work led to a greater taking into custody of how genes are arranged on chromosomes and how genetic material can be exchanged (during crossing over) in meiosis. Morgans experiments showed without any doubt that * the gene for eye colour in fruit fly is located on the X chromosome, and * hereditary factors can be exchanged between the X chromosom es of an individual.Morgan experimented with fruit flies (Drosophilia melanogaster) and determined that genes are carried on chromosomes. He used crossing over to determine locations of genes. He detect that sex chromosomes look different to each other, and that eye colour gene in Drosophilia was located on the X chromosome, leading to the discovery of sex linkage. Boveri experimented with sea urchins and showed that a complete set of chromosomes was needed for usual development and that the NUCLEUS of a cadre was concerned with inheritance.He postulated that each chromosome was different, chromosomes were transferred from one generation to the next during cell division, and that chromosomes must carry the many hereditary factors. Sutton he observed during meiosis that chromosomes behaved randomly and gametes receive alone one chromosome from each pair. Distinguish between the terms gene and allele A gene is a section of DNA that codes for proteins that expresses itself as the phenotype for example, two genes for eye colour. An allele is the alternative forms of a gene, i. e. for eye colour, B would code for blue while b for brown.