Description of impact
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes which alter membrane fluidity; and as signaling molecules. Hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol (opisthokonts) or cycloartenol (plants). Lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene.The steroid core structure is typically composed of seventeen carbon atoms, bonded in four "fused" rings: three six-member cyclohexane rings (rings A, B and C in the first illustration) and one five-member cyclopentane ring (the D ring). Steroids vary by the functional groups attached to this four-ring core and by the oxidation state of the rings. Sterols are forms of steroids with a hydroxy group at position three and a skeleton derived from cholestane.: 1785f Steroids can also be more radically modified, such as by changes to the ring structure, for example, cutting one of the rings. Cutting Ring B produces secosteroids one of which is vitamin D3. Examples include the lipid cholesterol, the sex hormones estradiol and testosterone,: 10–19 and the anti-inflammatory drug dexamethasone.A country is a distinct territorial body or political entity (i.e. a nation). It is often referred to as the land of an individual's birth, residence or citizenship. A country may be an independent sovereign state or part of a larger state, as a non-sovereign or formerly sovereign political division, a physical territory with a government, or a geographic region associated with sets of previously independent or differently associated people with distinct political characteristics. It is not inherently sovereign. Countries can refer both to sovereign states and to other political entities, while other times it can refer only to states. For example, the CIA World Factbook uses the word in its "Country name" field to refer to "a wide variety of dependencies, areas of special sovereignty, uninhabited islands, and other entities in addition to the traditional countries or independent states".The largest country in the world by geographical area is Russia, while the most populous is China, followed by India, the United States, and Indonesia. The newest United Nations (UN) member is South Sudan. Admission of new members requires the approval of the General Assembly; since 1991, UN membership has been reserved to sovereign states. Microstates are sovereign countries having a very small population or very small land area, usually both; examples of microstates include Vatican City, Monaco and San Marino.Impact date | 30 Aug 2019 |
---|
Related content
-
Research output
-
Psychology Vs Text Messaging: What Will Survive?
Research output: Other contribution
-
Should Text Messaging Start With A Prayer?
Research output: Other contribution
-
Roswell Ufo In Literature: Main Motives And Themes
Research output: Other contribution
-
Sports In The United States
Research output: Other contribution
-
What Efforts Are Being Taken To Protect Notions?
Research output: Other contribution