Genetics: Study of Biological Information

Genetics: Study of Biological Information

Genetics is the branch of biology dealing with heredity and variations of organisms and the genetic makeup and phenomena of an organism, type, group, or condition (Merriam-Webster Online Dictionary, 2010). In this course, it has been defined as "the study of how biological information is stored, utilized, and passed on from one generation to the next."

The biological information is stored within the cells as Deoxyribonucleic acid (DNA) which is responsible for the coding and reproducing of the cellular information. Proteins, amino acids, and ribonucleic acid are the other main components involved in biological information process.

The life of an organism relies on the cells ability to store, transcribe, and translate the genetic information in the cell.

The genetic material that carries all the hereditary information is the DNA and is found inside the nucleus of the cell. The DNA is a double helical structure whose backbone is composed of sugar-phosphate with nucleotide bases attached. There are four different nucleotide bases: adenine (a), cytosine (C), guanine (G) and thymine (T) plus a fifth one found in RNA: uracil (U) which takes the place of the thymine (T). Only a and T. Or U. can bind together and only C. And G. can bind together. This makes a strand of DNA 'complementary' to the strand being made (Genetics: Elementary human genetics, 2006).

The genetic information is basically instructions for making proteins (Alberts et al., n.d.). The proteins are made up of amino acids. The DNA is unwound in to two strands and the genetic code is transcribed on a strand of RNA; because DNA cannot leave the nucleus of the cell but RNA can leave the nucleus of the cell. The RNA then acts like a messenger delivering the genes sequence and finally translates the code information for the production of the protein. The protein decoded for plays a role in the formation and functions of the cell. The DNA of the cell is the same for all types of cells but the cells have different functions.

DNA is replicated by the use of DNA polymerase enzymes. The rate of error in the reproduction of the DNA strand is 1 in 100 million nucleotides. DNA is the storage of the genetic code but the RNA contains the actual template the protein is formed from. The RNA is broken down into three parts for this process: messenger RNA, transfer RNA, and ribosomal RNA. All forms of RNA cellular components are synthesized by RNA polymerases that are guided by the DNA. The process begins with transcription which precedes the translation. The translation is the synthesis of the proteins from the messenger RNA template. The gene expression of the cell, as known as the gene flow, is:

The hereditary information is passed from parent to child through the sexual chromosome of the mother and father. The information is then transcribed into the traits and phenotypes of the offspring depending on the dominance and recessive alleles within the gene (Berg, Tymoczko, & Stryer, n.d). The egg is fertilized by the sperm from the mother and their nuclei fuses together to form a zygote. The zygote contains 23 chromosomes from the mother and 23 from the father. From this combination of genes and the environmental conditions of the uterus, the traits and phenotypes of the individual are determined.

The principle of segregation for all organisms is as follows:

1. Hereditary traits are determined by specific genes. In the DNA molecule, genes are coded to specify a certain, single characteristic; this includes height, weight, eye color, etc. Any variations of the gene that correlates to the same trait are called alleles.

2. Individuals carry two genes for each trait, one from the mother's egg and one from the father's sperm. One of the genes will be dominant over the other. The dominant allele will mask the other, called the recessive allele. When the father gives a tall allele in regards to the height gene, and the mother gives a short allele, the offspring will be tall. This is because tall is dominant and short is recessive (Gene School, 2010).