Glycosidic Bond Definition and Examples

Glycosidic Bond Definition and Examples A glycosidic bond is a covalent bond that joins a carbohydrate to another functional group or molecule. A substance containing a glycosidic bond is termed a glycoside. Glycosides may be categorized according to elements involved in the chemical bond. Glycosidic Bond Example An N-glycosidic bond connects the adenine and ribose in the molecule adenosine. The bond is drawn as a vertical line between the carbohydrate and the adenine. O-, N-, S-, and C-glycosidic Bonds Glycosidic bonds are labeled according to the identity of the atom on the second carbohydrate or the functional group. The bond formed between the hemiacetal or hemiketal on the first carbohydrate and the hydroxyl group on the second molecule is an O-glycosidic bond. There are also N-, S-, and C-glycosidic bonds. Covalent bonds between the hemiacetal or hemiketal to  -SR form thioglycosides. If the bond is to SeR, then selenoglycosides form. Bonds to -NR1R2 are N-glycosides. Bonds to -CR1R2R3 are termed C-glycosides. The term aglycone refers to any compound ROH from which a carbohydrate residue has been removed, while the carbohydrate residue may be referred to as the glycone. These terms are most commonly applied to naturally occurring glycosides. ÃŽ ±-  and  ÃŽ ²-glycosidic Bonds The orientation of the bond may be noted, too.  ÃŽ ±-  and  ÃŽ ²-glycosidic bonds are based on the  stereocenter furthest from saccharide C1.  An ÃŽ ±-glycosidic bond occurs when both carbons share the same stereochemistry. Î’-glycosidic bond forms when the two carbons have different stereochemistry.

Geography of Hawaii Facts Information

Geography of Hawaii Facts Information Population: 1,360,301 (2010 Census estimate)Capital: HonoluluLargest Cities: Honolulu, Hilo, Kailua, Kaneohe, Waipahu, Pearl City, Waimalu, Mililani, Kahului, and KiheiLand Area: 10,931 square miles (28,311 sq km)Highest Point: Mauna Kea at 13,796 feet (4,205 m) Hawaii is one of the 50 states of the United States. It is the newest of the states (it joined the union in 1959) and it is the only U.S. state that is an island archipelago. Hawaii is located in the Pacific Ocean to the southwest of the continental U.S., southeast of Japan and northeast of Australia. Hawaii is known for its tropical climate, unique topography, and natural environment, as well as its multicultural population. Ten Geographic Facts About Hawaii Hawaii has been continuously inhabited since about 300 B.C.E. according to archeological records. It is believed that the earliest inhabitants of the islands were Polynesian settlers from the Marquesas Islands. Later settlers may have also migrated to the islands from Tahiti and introduced some of the ancient cultural practices of the region; however, there is a  debate about the early history of the islands.The British explorer Captain James Cook made the first recorded European contact with the islands in 1778. In 1779, Cook made his second visit to the islands and later published several books and reports on his experiences on the islands. As a result, many European explorers and traders began to visit the islands and they brought new diseases which killed a large portion of the islands population.Throughout the 1780s and into the 1790s, Hawaii experienced civil unrest as its chiefs fought for power over the area. In 1810, all of the islands that were inhabited became governed u nder a single ruler, King Kamehameha the Great and he established the House of Kamehameha which lasted until 1872 when Kamehameha V died. Following the death of Kamehameha V, a popular election led to Lunalilo controlling the islands because Kamehameha V had no heir. In 1873, Lunalilo died, also without an heir, and in 1874 after some political and social instability, governance of the islands went to the House of Kalakaua. In 1887 Kalakaua signed the Constitution of the Kingdom of Hawaii which took away much of his power. Following his death in 1891 his sister, Liliuokalani took the throne and in 1893 she attempted to create a new constitution.In 1893 a portion of Hawaiis foreign population formed a Committee of Safety and attempted to overthrow the Kingdom of Hawaii. In January of that year, Queen Liliuokalani was overthrown and the Committee of Safety created a provisional government. On July 4, 1894, the Provisional Government of Hawaii ended and the Republic of Hawaii was created which lasted until 1898. In that year Hawaii was annexed by the U.S. and it became the Territory of Hawaii which lasted until March 1959 when President Dwight D. Eisenhower signed the Hawaii Admission Act. Hawaii then became the 50th U.S. state on August 21, 1959. The islands of Hawaii are located about 2,000 miles (3,200 km) southwest of the continental U.S. It is the southernmost state of the U.S. Hawaii is an archipelago made up of eight main islands, seven of which are inhabited. The largest island by area is the island of Hawaii, also known as the Big Island, while the largest by population is Oahu. The other main islands of Hawaii are Maui, Lanai, Molokai, Kauai, and Niihau. Kahoolawe is the eighth island and it is uninhabited.The Hawaiian Islands were formed by undersea volcanic activity from what is known as a hotspot. As the Earths tectonic plates in the Pacific Ocean moved over millions of years, the hotspot remained stationary creating new islands in the chain. As a result of the hotspot, all of the islands were once volcanic, today, however, only the Big Island is active because it is located the closest to the hotspot. The oldest of the main islands is Kauai and it is located the farthest from the hotspot. A new island, called the Loihi Seamount, is also forming off the south coast of the Big Island. In addition to the main islands of Hawaii, there are also more than 100 small rocky islets that are a part of Hawaii. The topography of Hawaii varies based on the islands, but most of them have mountain ranges along with coastal plains. Kauai, for instance, has rugged mountains that go right up to its coast, while Oahu is divided by mountain ranges and also has flatter areas.Since Hawaii is located in the tropics, its climate is mild and summer highs are usually in the upper 80s (31ËšC) and winters are in the low 80s (28ËšC). There are also wet and dry seasons on the islands and the local climate on each island varies based on ones position in relation to the mountain ranges. Windward sides are typically wetter, while leeward sides are sunnier. Kauai has the second highest average rainfall on Earth.Because of Hawaiis isolation and tropical climate, it is very biodiverse and there are many endemic plants and animals on the islands. Many of these species are engendered and Hawaii h as the highest number of endangered species in the U.S. To learn more about Hawaii, visit the states official website.References Infoplease.com. (n.d.). Hawaii: History, Geography, Population and State Facts- Infoplease.com. Retrieved from: infoplease.com/us-states/hawaii.htmlWikipedia.org. (29 March 2011). Hawaii - Wikipedia, the Free Encyclopedia. Retrieved from: https://en.wikipedia.org/wiki/Hawaii