Team Number: 112 School Name: Tularosa High School Area of Science: Biology Project Title: Predicting the rate of spread of Treacher's Collins in a set enviroment. Project Abstract: http://mode.lanl.k12.nm.us/97.98/abstracts/112.html Interim Report: http://mode.lanl.k12.nm.us/97.98/interims/112.html Final Report: http://mode.lanl.k12.nm.us/97.98/finalreports/112/finalreport.html
Genetics is the study of how physical, biochemical and behavioral traits are transmitted from parent to offspring. The mechanisms of inheritance can be determined by genetics. Similarities between the parent and offspring can recur from generation in a repeated pattern.
In the 1900's Gregor Mendel described the patterns of inheritance. In his observation, he found that you inherit traits as seperate units that are inherited independently of the others. Later, the units Mendel described were named genes.
Soon after the rediscovery of Mendel's works, scientists realized that the patterns of inheritance that were described paralleled the actions of chromosomes in dividing all cells which later lead to intensive studies of cell division.
These intensive studies brought up the facts that every cell that divides comes from a preexisting cell. For example, all cells that makes up the human body where divided from the successive division of a single cell known as the zygote. The zygote formed by the union of the sperm and egg cell.
The majority of cells produced by the division of the zygote are in the composition of their heredity material, identical to one another and to the zygote itself. Each cell is composed of a jelly like layer of material known as the cytoplasm.
Cytoplasm contains many small structures. The nucleus is surrounded by the cytoplasmic material. Every nucleus contains a thread like chromosome. Chromosomes usually occur in pairs and vary in size and shape. Each member of the pair is known as a homoloques and they closelyresemble each other. The human body contains 23 pairs of chromosomes. Each chromosome in a cell contains a gene. Each gene is located at a particular site, or focus on the chromosome.
Mitosis is the process of cell division by which a new cell comes to have an identical number of chromosomes as the parent cell. When two chromosomes divide into two equal parts and travel to opposite ends of the cell. the process is alled mitosis division. After the mitosis division, the tow resulting cells contain the same number of chromosomes and genes as the original cell. Every cell formed from this process has the arrayof genetic material.
Simple one-celled organisms and some multicellular forms reproduce by mitosis; it is also the process by which organisms achieve growth and replace worn-out tissue. Higher organisms that reproduce sexually are fromed from the union of two special sex cells called the sperm and egg cells.
Gametes are produced by meiosis, the process by which germ cells divide. It differs from mitosis in one important way: In meiosis, asingle chromosome from each pair of chromosomes is transmitted from the original cell to each of the new cells. Thus, each gamete contains half to numbers of chromsomes that are found in the other body cells. When two gametes unite in fertilization, the resulting cell, called the zygote, contains the full, double set of chromosomes. Half of these chromosomes normally come from one parent and half from the other.
For more than 50 years the science of genetics was established and the patterns of inheritance through genes were clarified, the largest questions remained unanswered: HOw are the chromosomes and their genescopied so exactly from cell to cell, and how do they direct the structure and behavior of living things? Two American genetics provided one of the first important clues in the early 1940's. Working with fungi, they found that genes direct the formation of enzymes through the units of which they are composed. Each unit is produced by a specific gene. This work launched studies into the chemical nature of the gene and helped to establish the field of molecular genetics.