| Unit 3: Biology | ||||
Why do offspring resemble their parents? Genetics, a branch of biology, tries to answer these types of questions about inheritance. Geneticists have found that most aspects of life have a hereditary basis. Many traits can appear in more than one form. A trait is some aspect of an organism that can be described or measured. For example, human beings may have blond, red, brown, or black hair. They may have tongues that they can roll or not roll. (Try it! Can you roll your tongue? Can your parents?) They may have earlobes that are attached or free. The passing of traits from parents to offspring is called heredity.  In most organisms, including humans, genetic information is transmitted from one generation to the next by deoxyribonucleic acid (DNA). DNA makes up the genes that transmit hereditary traits. Each gene in the body is a DNA section with a full set of instructions. These instructions guide the formation of a particular protein. The different proteins made by the genes direct a body’s function and structure throughout life. Chromosomes carry the genes. They provide the genetic link between generations. The number of chromosomes in a cell is characteristic of the species. Some have very few, whereas others may have more than a hundred. You inherit half of your chromosomes from your mother and the other half from your father. Therefore, your traits are a result of the interactions of the genes of both your parents. |
Bio Words trait: an aspect of an organism that can be described or measured heredity: the passing of traits from parent to offspring gene: a unit of instruction located on a chromosome that produces or influences a specific trait in the offspring chromosome: threads of genetic material found in the nucleus of cells |
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