Genetic and Molecular Biology Essay Example | Topics and Well Written Essays - 750 words

Genetic and Molecular Biology - Essay Example The chromosome theory on inheritance said that Chromosomes are in pairs and genes, or their alleles, are located on the chromosomes. 4. Each of several Alternative forms of a Gene is called an Allele. Letters are used to represent Alleles: Capital Letters refer to a Dominant Allele that masks or hides expression of a recessive allele. Lowercase Letters refer to a Recessive Allele its expression is masked by a dominant allele. Yes, it is possible for more than two alleles of a gene to exist. 5. Scientists gradually learned about DNA in a curiously twisted fashion that is common in science. For one thing, the discovery of DNA required progress on three separate fronts: cytology (the study of cells through a microscope), genetics, and chemistry. Scientists working on DNA in the early 1950s used the term "gene" to mean the smallest unit of genetic information, but they did not know what a gene actually looked like structurally and chemically, or how it was copied, with very few errors, generation after generation. Nevertheless, many scientists continued to believe that DNA had a structure too uniform and simple to store genetic information for making complex living organisms. The genetic material, they reasoned, must consist of proteins, much more diverse and intricate molecules known to perform a multitude of biological functions in the cell. 6. Gene is a hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism. A chromosome is a grouping of coiled strands of DNA, containing many genes. 7. Each strand of DNA is a chain of chemical "building blocks", called nucleotides, of which there are four types: adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T). These allowable base components of nucleic acids can be polymerized in any