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Group of fat-soluble prohormones: Vitamin D

By Author ⋅ September 11, 2008 ⋅ Post a comment

The two major forms of which are vitamin D2 (or ergocalciferol) and vitamin D3 (or cholecalciferol). The term vitamin D also refers to metabolites and other analogues of these substances. Vitamin D3 is produced in skin exposed to sunlight, specifically ultraviolet B radiation.
Vitamin D plays an important role in the maintenance of organ systems.
[…]

Vitamin C or L-ascorbate

By Author ⋅ September 11, 2008 ⋅ Post a comment

Vitamin C or L-ascorbate is an essential nutrient for a large number of higher primate species, a small number of other mammalian species (notably guinea pigs and bats), a few species of birds, and some fish.
The presence of ascorbate is required for a range of essential metabolic reactions in all animals and plants. It is […]

Bacterial Conjugation

By Author ⋅ September 10, 2008 ⋅ Post a comment

Bacterial conjugation is the transfer of genetic material between bacteria through direct cell-to-cell contact. Discovered in 1946 by Joshua Lederberg and Edward Tatum, conjugation is a mechanism of horizontal gene transfer—as are transformation and transduction—although these mechanisms do not involve cell-to-cell contact.
Bacterial conjugation is often incorrectly regarded as the bacterial equivalent of sexual reproduction or […]

Vitamin A

By Author ⋅ April 8, 2008 ⋅ Post a comment

Vitamin A is an essential human nutrient. Its important part is the retinyl group, which can be found not in a single compound, but in several forms. In foods of animal origin, the major form of vitamin A is an alcohol (retinol), but can also exist as an aldehyde (retinal), or as an acid (retinoic […]

DNA from the Beginning

By Author ⋅ April 3, 2008 ⋅ Post a comment

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints, since it contains the instructions needed to construct […]

RNA world hypothesis

By Author ⋅ April 3, 2008 ⋅ Post a comment

The RNA world hypothesis proposes that a world filled with RNA (ribonucleic acid) based life predates current DNA (deoxyribonucleic acid) based life. RNA, which can store information like DNA and catalyze reactions like proteins (enzymes), may have supported cellular or pre-cellular life. Some theories as to the origin of life present RNA-based catalysis and information […]

Uncombable hair syndrome

By Author ⋅ March 19, 2008 ⋅ Post a comment

Uncombable hair syndrome is a rare structural anomaly of the hair shaft with variable penetrance (MIM 191480). It may become first apparent from 3 months to 12 years of age. The hair is normal in quantity and is usually silvery-blond or straw-colored. It is disorderly, it stands out from the scalp, and cannot be combed […]

Abiogenesis - Modern scientific research on the origin of life

By Author ⋅ March 18, 2008 ⋅ Post a comment

In the natural sciences, abiogenesis, the question of the origin of life, is the study of how life on Earth might have emerged from non-life. Scientific consensus is that abiogenesis occurred sometime between 4.4 billion years ago, when water vapor first liquefied, and 2.7 billion years ago, when the ratio of stable isotopes of carbon […]

Diabetes mellitus signs, symptoms and treatment

By Author ⋅ March 17, 2008 ⋅ Post a comment

The classical triad of diabetes symptoms is polyuria, polydipsia and polyphagia, which are, respectively, frequent urination; increased thirst and consequent increased fluid intake; and increased appetite. Symptoms may develop quite rapidly (weeks or months) in type 1 diabetes, particularly in children. However, in type 2 diabetes the symptoms develop much more slowly and may be […]

Diabetes mellitus