Cholera - its global impact
Cholera Cholera is an infectious disease caused by the bacterium Vibrio cholera, which usually spreads through contaminated water. It affects the absorption of water in the small intestine and in severe cases produces severe diarrhoea. The most dangerous aspect of Cholera is the immense loss of fluid that can occur within a few days. Without treatment within 24 hours of developing the disease, the loss of fluid can be fatal. Many cases, such as those in Zimbabwe, require hospitalisation of infected people so that fluids can be administered straight into the bloodstream with the use of a drip. Cholera bacteria occur naturally in coastal waters, where they attach to tiny crustaceans called Copepods. The Cholera bacteria travel with the Copepods, spreading worldwide as the crustaceans follow their food sources, which are certain types of algae and plankton. These grow rapidly when the water temperatures rise and algae growth is further increased by the urea found in sewage and agricultural runoff. Therefore most Cholera outbreaks occur in spring and autumn when ocean surface temperatures and algae blooms are at their highest. More algae mean more Copepods, and more Copepods mean more Cholera bacteria. The map on the left shows that the areas that Cholera is discovered in are situated below the Brandt line. This is because these areas are surrounded by warm oceans where the
The number of fatalities that result from volcanic and seismic natural hazards is related to the level of development in the country in which they occur. Discuss.
The number of fatalities that result from volcanic and seismic natural hazards is related to the level of development in the country in which they occur. Discuss. A natural hazard is an event, linked to the physical environment, which is considered to have a negative effect on humans. The event is also seen to be unpreventable by humans. However, an event such as a volcanic eruption that has no effect on human beings is considered a natural phenomenon rather than a natural hazard. It is the presence of humans, in an area that such an event occurs, that allows it to be termed a hazard. Although humans cannot prevent these occurrences, they have a role to play in the event's extremity as a natural hazard. For example, volcanic eruptions have been present throughout history, but it is not until settlements are built on the rich soils they form that they become a hazard. This essay I will evaluate the extent to which the level of development in a country affects the number of fatalities caused by volcanic and seismic natural hazards. A volcanic natural hazard is a volcanic eruption. Volcanoes are formed at convergent and divergent plate boundaries and also at hot spots. At convergent plate boundaries eruptions tend to be from a vent, as oceanic crust is forced beneath another plate, the extremities of heat and pressure leads to the partial melting of the crust which is being
Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst
Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst Variables * Amount of celery * Concentration of celery, more or less watered down. * Concentration of Hydrogen Peroxide (H202) * The amount of H202 * The temperature of H202 I am going to vary the concentration of the hydrogen peroxide. I think that varying the concentration of the liquid will be the best experiment to do and will hopefully give a strong set of results, which will enable me to obtain clear conclusions. Prediction The rate of an enzyme- controlled reaction depends on the temperature, pH, and concentrations of the enzyme and its substrate. The more enzyme molecules produced by a cell, the faster the reaction will proceed. Similarly, an increase in the substrate concentration will speed up the reaction if there are enough enzymes molecules to cope with the additional substrate. Therefore by diluting the hydrogen peroxide with water, this will decrease the rate of decomposition of the H202, and the less gas will be given off. The enzyme in the experiment is catalase. Hydrogen peroxide is poisonous and the catalase works to render the hydrogen peroxide harmless by breaking it down to water and oxygen. If the concentration of H202 is less, then there is more water present, and there are less hydrogen peroxide molecules, so there is less for the catalase to
Was the collapse of the USSR historically inevitable?
Was the collapse of the USSR historically inevitable? The twenty fifth of December 1991, Mikhail Gorbachev resigns as President of The Soviet Union and the country is dissolute in fifteen republics after an existence of nearly seventy years. Before this moment, less or none historians predicted this collapse. Nevertheless, one can ask the question whether this collapse was historically inevitable or not. The aim of this essay is not to rewrite History but explain what has lead to the end of the Soviet Union. First of all, this essay will describe shortly some important steps of the Soviet History after the Second World War and in the context of the Cold War, in order to help the understood of the final collapse. Even though the last years of the soviet regime were crucial, former events and policies influenced the Breakup of USSR. In the second part, I will analyze how some events and factors, such as economy, nationalism, internal and external pressures, personalities and the war of Afghanistan made this collapse inevitable. Even though some scholars, such as Gaddis1, argue that the end of the cold war and the collapse of Soviet Union were not historically expected, this essay will show that it seems inevitable. In order to understand the Collapse of the Soviet Union, some historical facts need to be reminded2. After the death of Stalin, Nikita Khrushchev became General
Investigate the effect of pH on Trypsin
Biology Coursework Plan Aim Investigate the effect of pH on Trypsin Prediction / hypothesis * pH will affect trypsin action * as pH increases, tryrpsin will show increasing activity up to an optimum pH * the action of the enzyme trypsin on the substrate egg albumen will be at a maximum at an optimum pH of around 7 (neutral) to 8 (slightly alkaline) see later about pH of duodenum * as pH continues above this, trypsin activity will decrease Background / Introduction Proteins are complex organic compounds consisting of amino acids joined by peptide bonds which form highly folded three dimensional or tertiary structures. The bonds that maintain the tertiary structure of the protein are a result of interactions between the R groups of the amino acids: disulphide bridges (strong covalent), hydrogen (weak) bonds, ionic or electrovalent bonds, hydrophobic interactions. Enzymes, such as trypsin, are globular proteins with a specific shaped active site into which the correct substrate can fit. trypsin protein / polypeptide peptides Trypsin is a protease enzyme: a hydrolytic or digestive protein that cleaves peptide bonds. It is produced in the pancreas in the form of trypsinogen, and is then transported to the duodenum of the small intestine, where the digestion of proteins to polypeptides and amino acids begins. The pH
Duty and desire in Jane Eyre
How is the conflict between duty and desire explored in these texts? Desire is a term conveying a longing for a certain object, person or outcome. It is an emotion from the heart and is unaffected by social opinion. Duty, in contrast, is a moral obligation to an act, which is perceived to be selfless. The decisions made regarding these emotions are significant throughout 'Jane Eyre' and 'Wide Sargasso Sea'. However, these definitions were more extreme during the time that Brontë and Rhy's texts were written. In the 19th century, it was considered a completely selfish act for women to show desire, it was a vulgar emotion that women were expected to control and conceal. The female role during the 1800's was limited; they were expected to be passive and were passed from father to husband, similar to a possession. To perform one's duty to society was regarded as an unspoken rule imposed on all women, therefore, women never truly had the chance to express their true identity or gain real independence. The 19th century conflict between duty and desire was a key topic written about by many authors, predominately women, who illustrated personal experiences and beliefs through the characters and their decisions. In both Bronte's and Rhy's novels the authors illustrate the limitations imposed on women, society's views and expectations concerning the conflict, and the importance of
ASDA's Ownership
Task 1: Business ownership ASDA's Ownership A). ASDA is a public limited company, which is also known as a PLC. An American retailing company called WAL-MART owns ASDA. Its shareholders own the company and this causes the ownership to constantly change, as the shares are constantly bought and sold. Most of the companies' shareholders are generally, old aged pensioners, banks and insurance companies. Before a PLC can be launched, they must have £50,000 or more and it must have a good financial record and, there must be enough people interested in buying shares in order to have a successful floatation. Floatation is when a company is on the Stock Exchange and is then launched to the public. WINES PLUS' Ownership Wines Plus is a partnership and is run by its owners. A partnership can be of a maximum of 2-20 people. The partners of the business share the responsibilities and risks of the business. Usually, if the partners have different skills, this provides the business with greater aspects as a different range of services can be offered and more profits can be made. Also, in some partnerships, there are also some sleeping partners. These are people that invest money into the business and receive a share of profits made but they don't have a say of how the business should be run. Before starting the business some partners sign a deed. This deed is called the Deed Of
Freuds Psychosexual Stages of Development
Freud's Psychosexual Stages of Development Freud advanced a theory of personality development that centred on the effects of the sexual pleasure drive on the individual consciousness. The following five stages are based around the notion that with each stage, the child's libido becomes centred around certain erogenous zones. The Oral Stage The oral stage begins at birth, when the oral cavity is the primary focus of libidal energy. The child, of course, preoccupies himself with nursing, with the pleasure of sucking and accepting things into the mouth. The oral character who is frustrated at this stage, whose mother refused to nurse him on demand or who truncated nursing sessions early, is characterized by pessimism, envy, suspicion and sarcasm. The overindulged oral character, whose nursing urges were always and often excessively satisfied, is optimistic, gullible, and is full of admiration for others around him. The stage finishes at the weaning stage. The stage lasts approximately one and one-half years. The Anal Stage At one and one-half years, the child enters the anal stage. With the advent of toilet training comes the child's obsession with the erogenous zone of the anus and with the retention or expulsion of the faeces. This represents a classic conflict between the id, which derives pleasure from expulsion of bodily wastes, and the ego and superego, which
Cellular Respiration and the Role of Mitochondria
Cellular Respiration and the Role of Mitochondria Cellular respiration is the process of oxidising food molecules, such as glucose, to carbon dioxide and water and releasing the covalent bond energy in the form of ATP for use by all the energy-consuming activities of the cell. Mitochondria are membrane-enclosed organelles distributed through the cytosol of most eukaryotic cells. They are where cellular aerobic respiration occurs; indeed cells without mitochondria cannot respire aerobically. Cellular respiration consists of two broad phases, initially, glycolysis (the breakdown of glucose to pyruvic acid) Occurs, this is followed by the oxidation of pyruvic acid to carbon dioxide and water. In eukaryotes, glycolysis occurs in the cytosol (The fluid in which cell organelles are suspended). The remaining processes take place in the mitochondria. The first stage, glycolysis is the anaerobic catabolism of glucose, it occurs in almost all cells. The process uses glucose and co-enzyme NAD (Nicotinamide Adenine Dinucleotide), and yields 2 molecules of Pyruvic acid, as below C6H12O6 + 2NAD+ -> 2C3H4O3 + 2NADH + 2H+ The free energy stored in 2 molecules of pyruvic acid is somewhat less than that in the original glucose molecule. Some of this difference is captured in 2 molecules of ATP. The Krebs Cycle then decarboxylates the pyruvic acid resulting in a 2-carbon fragment of
The structure and function of the ileum in relation to absorption and digestion.
SUMUDU LANKATILAKE 7-FEB-03 THE STRUCTURE AND FUNCTION OF THE ILEUM IN RELATION TO ABSORPTION AND DIGESTION The ileum is the second part of the small intestine located after the duodenum. It has a vital function in digestion and has a suitable structure to accommodate for its functions. The ileum is 6 meters long and the main site foe the absorption of the soluble products of digestion. The ileum is efficient at this for the following reasons: * It is fairly long and presents a large absorbing suface to the digested food. * Its internal surface is greatly increased by circular folds bearing thousands of projections called villi. These villi are about 0.56mm long and may be finger like or flattened in shape. * The lining epithelium is very thin and the fluids can pass rapidly through it. The outer membrane of each epithelial cell has microvilli which increase the exposed surface of the cell by 20 times. * There is a dense network of blood capillaries in each villus for quick absorption and maintainance of the concentration of the concentration gradient. * The villi possess smooth muscle fibres that contract and relax and mix the food up and bring it into contact with the epithelial cells of the absorptive surface. * Each villus has a lacteal for the absorption of fatty acids and glycerol, most of which combine to form fats. The ileum is made up of 4 layers:
