Diabetes mellitus results from a deficiency in the amount of insulin released from the pancreas in response to glucose (type I) or from a decrease in the ability of muscle and fat cells to respond to insulin (type II). In both types, the regulation of blood glucose is impaired, leading to persistent hyperglycemia and numerous other possible complications in untreated patients such as tissue damage, raises the risk of heart-attack, kidney disease and vision deterioration. Type I diabetes is caused by an autoimmune process that destroys the insulin-producing B cells in the pancreas. Also called insulin-dependent diabetes, this form of the disease is generally responsive to insulin therapy. Most Americans with diabetes mellitus have type II, but the underlying cause of this form of the disease is not well understood.
Chromosomes can exchange genetic information during a process called "crossing over." This occurs when homologous chromosomes are lined up in pairs. This recombination of maternal and paternal genetic material is a key feature of meiosis.
The two strands are held together by hydrogen bonds between the bases, with adenine forming a base pair with thymine, and cytosine forming a base pair with guanine.
