Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes, which have no membrane-bound organelles. Eukaryotes belong to Eukarya, their name comes from the Greek εὖ and κάρυον. Eukaryotic cells contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, in addition, some cells of plants and algae contain chloroplasts. Unlike unicellular archaea and bacteria, eukaryotes may be multicellular and include organisms consisting of many cell types forming different kinds of tissue. Animals and plants are the most familiar eukaryotes. Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion. In mitosis, one cell divides to produce two genetically identical cells. In meiosis, DNA replication is followed by two rounds of cell division to produce four haploid daughter cells; these act as sex cells. Each gamete has just one set of chromosomes, each a unique mix of the corresponding pair of parental chromosomes resulting from genetic recombination during meiosis.
The domain Eukaryota is monophyletic and makes up one of the domains of life in the three-domain system. The two other domains and Archaea, are prokaryotes and have none of the above features. Eukaryotes represent a tiny minority of all living things. However, due to their much larger size, their collective worldwide biomass is estimated to be about equal to that of prokaryotes. Eukaryotes evolved 1.6–2.1 billion years ago, during the Proterozoic eon. The concept of the eukaryote has been attributed to the French biologist Edouard Chatton; the terms prokaryote and eukaryote were more definitively reintroduced by the Canadian microbiologist Roger Stanier and the Dutch-American microbiologist C. B. van Niel in 1962. In his 1937 work Titres et Travaux Scientifiques, Chatton had proposed the two terms, calling the bacteria prokaryotes and organisms with nuclei in their cells eukaryotes; however he mentioned this in only one paragraph, the idea was ignored until Chatton's statement was rediscovered by Stanier and van Niel.
In 1905 and 1910, the Russian biologist Konstantin Mereschkowski argued that plastids were reduced cyanobacteria in a symbiosis with a non-photosynthetic host, itself formed by symbiosis between an amoeba-like host and a bacterium-like cell that formed the nucleus. Plants had thus inherited photosynthesis from cyanobacteria. In 1967, Lynn Margulis provided microbiological evidence for endosymbiosis as the origin of chloroplasts and mitochondria in eukaryotic cells in her paper, On the origin of mitosing cells. In the 1970s, Carl Woese explored microbial phylogenetics, studying variations in 16S ribosomal RNA; this helped to uncover the origin of the eukaryotes and the symbiogenesis of two important eukaryote organelles and chloroplasts. In 1977, Woese and George Fox introduced a "third form of life", which they called the Archaebacteria. In 1979, G. W. Gould and G. J. Dring suggested that the eukaryotic cell's nucleus came from the ability of Gram-positive bacteria to form endospores. In 1987 and papers, Thomas Cavalier-Smith proposed instead that the membranes of the nucleus and endoplasmic reticulum first formed by infolding a prokaryote's plasma membrane.
In the 1990s, several other biologists proposed endosymbiotic origins for the nucleus reviving Mereschkowski's theory. Eukaryotic cells are much larger than those of prokaryotes, having a volume of around 10,000 times greater than the prokaryotic cell, they have a variety of internal membrane-bound structures, called organelles, a cytoskeleton composed of microtubules and intermediate filaments, which play an important role in defining the cell's organization and shape. Eukaryotic DNA is divided into several linear bundles called chromosomes, which are separated by a microtubular spindle during nuclear division. Eukaryote cells include a variety of membrane-bound structures, collectively referred to as the endomembrane system. Simple compartments, called vesicles and vacuoles, can form by budding off other membranes. Many cells ingest food and other materials through a process of endocytosis, where the outer membrane invaginates and pinches off to form a vesicle, it is probable that most other membrane-bound organelles are derived from such vesicles.
Alternatively some products produced by the cell can leave in a vesicle through exocytosis. The nucleus is surrounded with pores that allow material to move in and out. Various tube- and sheet-like extensions of the nuclear membrane form the endoplasmic reticulum, involved in protein transport and maturation, it includes the rough endoplasmic reticulum where ribosomes are attached to synthesize proteins, which enter the interior space or lumen. Subsequently, they enter vesicles, which bud off from the smooth endoplasmic reticulum. In most eukaryotes, these protein-carrying vesicles are released and further modified in stacks of flattened vesicles, the Golgi apparatus. Vesicles may be specialized for various purposes. For instance, lysosomes contain digestive enzymes that break down most biomolecules in the cytoplasm. Peroxisomes are used to break down peroxide, otherwise toxic. Many protozoans have contractile vacuoles, which collect and expel excess water, extrusomes, which expel material used to deflect predators or capture prey.
In higher plants, most of a cell's volume is taken up by a central vacuole, which most
John Boyle was a United States Representative from Kentucky and a United States District Judge of the United States District Court for the District of Kentucky. Born on October 28, 1774, at "Castle Woods" in Botetourt County, Boyle moved with his father to Whitleys Station, Kentucky in 1779 and was educated by private tutors and in private schools, he read law and was admitted to the bar in 1797. He entered private in Lancaster, Kentucky from 1797 to 1802, he was deputy counselor at law for the Kentucky Court of Quarter Sessions in 1797. He was a member of the Kentucky House of Representatives in 1800. Boyle was elected as a Democratic-Republican from Kentucky's 2nd congressional district to the United States House of Representatives of the 8th, 9th and 10th United States Congresses, serving from March 4, 1803, to March 3, 1809, he was one of the managers appointed by the United States House of Representatives, in January 1804, to conduct the impeachment proceedings against Judge John Pickering, and, in December of the same year, against Associate Justice Samuel Chase.
He was Chairman of the Committee on Public Land Claims for the 9th and 10th United States Congresses. Boyle declined the position, he was a Judge of the Kentucky Court of Appeals from 1809 to 1826, serving as Chief Judge from 1810 to 1826. Boyle received a recess appointment from President John Quincy Adams on October 20, 1826, to a seat on the United States District Court for the District of Kentucky vacated by Judge Robert Trimble, he was nominated to the same position by President Adams on December 13, 1826. He was confirmed by the United States Senate on February 12, 1827, received his commission the same day, his service terminated on January 1834, due to his death near Danville, Boyle County, Kentucky. He was interred in Bellevue Cemetery in Danville. United States Congress. "John Boyle". Biographical Directory of the United States Congress. John Boyle at the Biographical Directory of Federal Judges, a public domain publication of the Federal Judicial Center. History of the Sixth Circuit Allen, William B..
A History of Kentucky: Embracing Gleanings, Antiquities, Natural Curiosities and Biographical Sketches of Pioneers, Jurists, Statesmen, Mechanics, Farmers and Other Leading Men, of All Occupations and Pursuits. Bradley & Gilbert. P. 277. Retrieved 2008-11-10
What Happened to the La Las is the tenth studio album by the American rock band moe. It was released on January 24, 2012.. As per usual, most of the songs on this album were road-tested prior to being recorded. "The Bones Of Lazarus" is a reworking of an earlier live favorite called "Lazarus." The composition was renamed in recognition of The Bones of Lazarus. Two of the songs - "Chromatic Nightmare" and "Suck A Lemon" - were conceived for a themed 2010 performance known as "The Electric Lemoe.nade Acid Test". Although "Haze" was written and sung by guitarist Al Schnier, the mic was handed over to bassist Rob Derhak for this album version, he has handled the vocals on most versions performed since. A deluxe edition of the album was released with a second disc containing acoustic versions of all the songs. "The Bones of Lazarus" – 3:56 "Haze" – 5:12 "Downward Facing Dog" – 7:54 "Rainshine" – 4:39 "Smoke" – 3:39 "Paper Dragon" – 4:48 "Chromatic Nightmare" – 3:43 "Puebla" – 4:10 "One Way Traffic" – 2:54 "Suck a Lemon" – 4:30 Rob Derhak – lead vocals, bass guitar Al Schnier – lead vocals, keyboards, mandolin Chuck Garvey – lead vocals, guitar Vinnie Amico – drums Jim Loughlin – percussion, MalletKat, DrumKat, Rhodes on "Downward Facing Dog"