Lysosomal Storage Disorders

Macromolecules large Lysosomes are intracellular compartments in which macromolecules are molecules such as proteins, carbohydrates, and nucleic acids broken down in an acidic environment. Various classes of lysosomal storage disorders arise when there are defects in specific enzymes, and the manifestations of these disorders depend upon the class of macromolecule whose breakdown is affected. Gaucher's Disease. The most common lysosomal storage disorder is Gaucher's disease, caused by a...

Light and Radiation

Radiation refers to two different phenomena light and high-energy particles. Visible light represents a small slice of the electromagnetic spectrum, which includes long-wavelength (low-energy) radio waves and short-wavelength (high-energy) ultraviolet waves, plus X rays and gamma rays. These high-energy forms can directly disrupt DNA by breaking its chemical bonds. In severe cases, this can break apart chromosomes, causing chromosome aberrations. More often, they create mutagenic free radicals...

Viewing Chromosomes

Biologists first tried to visualize the chromosomes in a human cell in the late nineteenth century, with estimates of the total number ranging from 30 to 80. As methods to untangle and stain chromosomes improved, the count narrowed to 46 or 48, and by 1956 was confirmed as 46, or 23 pairs. By 1959, the first chromosomal abnormalities were identified using size and crude staining patterns to distinguish the chromosomes. In the 1970s, vastly cytogeneticists scien- improved staining techniques...

Schizophrenia and Bipolar Disorder

Schizophrenia is a disorder characterized by psychotic symptoms such as hallucinations, delusions, and disordered thinking, as well as deficits in emotional and social behavior. Numerous family, twin, and adoption studies have provided substantial evidence for genetic factors in the etiology of this dis- etiology causation of disease, or the study of causation order. Nongenetic factors also appear to play an important role. The risk for relatives of an individual with schizophrenia is 6.5...