Cell
Essays

The Invader Within Eukaryotic organisms are defined by the existence of organelles within the cell format. Two of the most important of these organelles are chloroplasts and mitochondria.

The study in question was conducted to determine the mechanisms by which inhaled ultrafine particles are further translated to other areas of the body. The researchers related that "Within hours after the respiratory…

According to Waryasz & McDermott (2009), the global prevalence of diabetes among people aged between 20 and 79 rose to 6.4% affecting 285 million people in 2010 and the rate will rise to 7.7% affecting 439 million…

Rock looked at the open letter lying on the bathroom floor in front of the toilet. "Damn!"

Officer Jim Rawlins, a fourteen-year veteran of the Anytown Police Department spent the morning working with Sadie. He hid a series of balls around his backyard, giving the golden retriever praise and pets every time…

Under serious threats to a country's national security, it is unavoidable to commit some abuses against freedom of the press and individual rights."

The concept of aging has many intrinsic and extrinsic factors that act as markers on an individual organism. Ignoring mortality associated with external environmental factors, very few organisms can be said to have cellular immortality with no decrease in cellular function or repeat division in normal diploid cells. Cellular senescence is a normal process that halts cellular division after a set of cycles of replication. Senescent cells can remain completely functional but lose the programmed process of replication. The normal pathway for senescent cells is either aging with metabolic pathways continuing for the cell or programmed cell death which is known as apoptosis that occurs when cellular function changes, a specific lifetime is reached for the cell or the cell is damaged. The multicellular cnidarians known as a Hydra has been shown to have a complete lack of senescence in cellular function with cells dividing frequently and continuously and being sloughed off at the tips of appendages and new stem cells continuously repopulating (Watanabe 2009). The hydra organism effectively shows no aging (Martinez 1998) and studies of the Hydra genome show that the organism has a mutation in the expression of the p53 gene that manifests as a lack of p53 protein in hydra cells (Rutkowski 2010). The link between a lack of p53 expression and aging has been studied exhaustively with the inverse relationship between tumor suppression and cell immortality at balance with the expression of the protein. What has not been studied under such significant scrutiny has been the relationship between p53 expression and cellular senescence which is the halting of cellular processes to form a dormant cell. The tradeoff for having no pathway to halt cellular activity is continuous cell division and replenishment which the hydra has exploited to live an immortal life. For a more complex animal with differentiated organ systems the nature of p53 tumor suppression and "immortality" is a legitimate tradeoff between insuring that cancer cells become dormant and undergo apoptosis (programmed cell death) and renewing the organ systems of the body.

The author bases his understanding of osteoporosis in humans on the research data from experiments with rodents, which shows estrogen deficiency triggers osteoclast activity. Increased osteoclast activity is another way…

Scientific method is a plan of investigation that uses testing an idea or hypothesis, working through the experiment in either a quantitative or qualitative manner (e.g. As long as it is measurable), testing those…

¶ … aid President George W. Bush in policy formulation. It is an all-inclusive paper dealing with a wide range of issues such as the American economy in general- discussing issues such as budget deficits, tax cuts,…