Biology Essays and Term Papers

in the ovaries, two small organs set in the pelvic cavity below and to either side of the bellybutton. The ovaries also secrete the hormones estrogen and progesterone. The estrogen hormone causes the thickening of the lining of the uterus and vagina…

four different types are : A, B, AB, and O. As you might guess, AB is a combination of, well, A and B. Each letter refers to a kind of antigen (protein) on the surface of the red blood cells. Red blood cells and other formed elements only make…

Lestra! It sounds like a musical to me. I imagine scads of scantily clad showgirls with big headdresses kicking it Vegas Style as the dance and sing the praises of Olestra, the fat subsitute. Oh! Oh! O-Les-Tra -…

of life; probably from when we first arose as a species (they would have been evolving right along with us). These formidable agents of infection don't survive in the fossil record but evidence from ancient civilisations reveals some of the long history…

characteristic. This vast amount of vital information encoded in DNA is organized into genes. A gene is a segment of DNA that transmits information from parent to offspring. When a cell prepares to divide, the DNA molecule coils and twists into…

is equally susceptible. Birth defects are not merely a medical problem. They have profound effects on the social and psychological well being of their family and friends. In the normal course of fetal development, cells migrate to their appropr…

cell wall but lacks a nucleus and membrane - bound organelles. A bacterium's single DNA molecule is not coiled around proteins to form chromosomes. Instead, its face of the plasma membrane like a rope attached to the inner wall of a tent. First the…

likely outcome of genetic crosses. Capital letters refer to dominant alleles, and lowercase letters refer to recessive alleles. Capital and lowercase forms of the same letter must be used to designate the two forms of one gene. The allele for a dominant…

existence of viruses near the end of the nineteenth century. At that time, European scientists were seeking to identify the infectious agent responsible for tobacco mosaic disease, a disease that stunts the growth of tobacco plants and makes their…

only ones characterized by prokaryotic organization. Too tiny to see with the naked eye, a bacterial cell is usually one of three basic shapes; bacillus, a rod shaped cell; coccus, a spherical cell; or spirillum, a spiral cell. A few kinds of bacteria…