SUMMARY / RELATED TOPICS

Cytosol

The cytosol known as intracellular fluid or cytoplasmic matrix, or groundplasm, is the liquid found inside cells. It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into many compartments. In the eukaryotic cell, the cytosol is surrounded by the cell membrane and is part of the cytoplasm, which comprises the mitochondria and other organelles; the cytosol is thus a liquid matrix around the organelles. In prokaryotes, most of the chemical reactions of metabolism take place in the cytosol, while a few take place in membranes or in the periplasmic space. In eukaryotes, while many metabolic pathways still occur in the cytosol, others take place within organelles; the cytosol is a complex mixture of substances dissolved in water. Although water forms the large majority of the cytosol, its structure and properties within cells is not well understood; the concentrations of ions such as sodium and potassium are different in the cytosol than in the extracellular fluid.

The cytosol contains large amounts of macromolecules, which can alter how molecules behave, through macromolecular crowding. Although it was once thought to be a simple solution of molecules, the cytosol has multiple levels of organization; these include concentration gradients of small molecules such as calcium, large complexes of enzymes that act together and take part in metabolic pathways, protein complexes such as proteasomes and carboxysomes that enclose and separate parts of the cytosol. The term "cytosol" was first introduced in 1965 by H. A. Lardy, referred to the liquid, produced by breaking cells apart and pelleting all the insoluble components by ultracentrifugation; such a soluble cell extract is not identical to the soluble part of the cell cytoplasm and is called a cytoplasmic fraction. The term cytosol is now used to refer to the liquid phase of the cytoplasm in an intact cell; this excludes any part of the cytoplasm, contained within organelles. Due to the possibility of confusion between the use of the word "cytosol" to refer to both extracts of cells and the soluble part of the cytoplasm in intact cells, the phrase "aqueous cytoplasm" has been used to describe the liquid contents of the cytoplasm of living cells.

Prior to this, other terms, including hyaloplasm, were used for the cell fluid, not always synonymously, as its nature was not clear. The proportion of cell volume, cytosol varies: for example while this compartment forms the bulk of cell structure in bacteria, in plant cells the main compartment is the large central vacuole; the cytosol consists of water, dissolved ions, small molecules, large water-soluble molecules. The majority of these non-protein molecules have a molecular mass of less than 300 Da; this mixture of small molecules is extraordinarily complex, as the variety of molecules that are involved in metabolism is immense. For example, up to 200,000 different small molecules might be made in plants, although not all these will be present in the same species, or in a single cell. Estimates of the number of metabolites in single cells such as E. coli and baker's yeast predict that under 1,000 are made. Most of the cytosol is water; the pH of the intracellular fluid is 7.4. While human cytosolic pH ranges between 7.0 - 7.4, is higher if a cell is growing.

The viscosity of cytoplasm is the same as pure water, although diffusion of small molecules through this liquid is about fourfold slower than in pure water, due to collisions with the large numbers of macromolecules in the cytosol. Studies in the brine shrimp have examined. Although water is vital for life, the structure of this water in the cytosol is not well understood because methods such as nuclear magnetic resonance spectroscopy only give information on the average structure of water, cannot measure local variations at the microscopic scale; the structure of pure water is poorly understood, due to the ability of water to form structures such as water clusters through hydrogen bonds. The classic view of water in cells is that about 5% of this water is bound in by solutes or macromolecules as water of solvation, while the majority has the same structure as pure water; this water of solvation is not active in osmosis and may have different solvent properties, so that some dissolved molecules are excluded, while others become concentrated.

However, others argue that the effects of the high concentrations of macromolecules in cells extend throughout the cytosol and that water in cells behaves differently from the water in dilute solutions. These ideas include the proposal that cells contain zones of low and high-density water, which could have widespread effects on the structures and functions of the other parts of the cell. However, the use of advanced nuclear magnetic resonance methods to directly measure the mobility of water in living cells contradicts this idea, as it suggests that 85% of cell water acts like that pure water, while the remainder is less mobile and bound to macromolecules; the concentrations of the other ions in cytosol are quite different from those in extr

Grant Watts

Grant Watts is an English retired professional footballer who played as a forward. Watts began his youth career with Crystal Palace and signed professional terms in August 1992, he made his senior debut on 16 December 1992 scoring in a 2–1 home win over Liverpool in the League Cup. His League debut followed three days and he went on to make four league appearances that season and three more in the League Cup. However, after suffering a broken leg he joined Colchester United on loan and Gillingham. After leaving Gillingham, Watts played non-league football for Sutton United, Welling United, Banstead Athletic, Egham Town and Bromley. Watts is now a coach at Holmesdale. Grant Watts at Post War English & Scottish Football League A–Z Player's Database Grant Watts at holmesdale.net Grant Watts at Soccerbase Since 1888... The Searchable Premiership and Football League Player Database

Christopher Newton (criminal)

Christopher J. Newton was an American murderer executed in the state of Ohio in 2007. Christopher Newton received the death penalty for the 2001 aggravated murder of his cellmate, Jason Brewer. At the time of the murder, Newton was imprisoned for attempted aggravated burglary of his father's home, an offense he committed a few weeks after his release from prison for a prior attempted aggravated burglary. Newton killed Brewer in their cell by stomping on his neck and head and strangling him with a strip of cloth. According to the opinion of the Ohio Supreme Court affirming the death penalty, Newton laughed while responding officials tried to resuscitate Brewer, having smeared Brewer's blood on his face and drunk some of it. Newton admitted that another inmate had hired him to assault Brewer, that he was ready to die in prison and knew that murdering another inmate would warrant the death penalty. According to the Ohio Supreme Court, numerous psychiatrists and psychologists had examined Newton over the years, resulting in various diagnoses.

At the capital trial, a defense psychologist testified that Newton had several mental health disorders, including "mood disorder" and symptoms of PTSD. In response, a government psychiatrist reviewed the mental health history and rebutted the defense expert; the court denied defense funds for neuropsychiatric tests to explore other types of mental disability. The trial was before a three-court panel of judges who, after hearing the evidence, imposed the death penalty. A controversy arose regarding the delay in Newton's execution. Subsequently, his veins were difficult to locate, which made administration of the injections difficult, it took over 10 attempts before the execution was completed. The problems with Newton's execution occurred one year after the 90 minute execution of fellow Ohio inmate, Joseph Lewis Clark. Capital punishment in Ohio Capital punishment in the United States List of people executed in Ohio http://www.sanduskyregister.com/articles/2007/05/24/front/289501.txt https://web.archive.org/web/20070927174320/http://www.supremecourtofohio.gov/Communications_Office/summaries/2006/0125/030565.asp http://ohiodeathpenaltyinfo.typepad.com/ohio_death_penalty_inform/files/NewtonOSCTbrief.doc Death Penalty Appeal - Detail.

Attorney General - State of Ohio. Retrieved on 2007-11-15. Christopher J. Newton; the Clark County Prosecuting Attorney. Retrieved on 2007-11-15