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University Degree: Microbiology

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  1. Free essay

    How had research over the past 25 years led us to think that microbes may be able to survive in extraterrestrial environments?

    Space explorations have revealed other planets with environmental extremes analogous to those found on earth. Therefore the discovery of extremophiles has made the search for extraterrestrial life more plausible. Furthermore, as more extremophiles are uncovered in what previously were thought to be uninhabitable environments, our view of the conditions required for life becomes less restricted. Extremophiles are found in all domains of life; from radiation-resistant bacteria (Anderson et al 1956) to extreme sunflowers thriving in salt marshes (Rieseberg et al 2003). However, research over the past 25 years has shown that microbes are the most abundant group of extremophiles (Satyanarayana et al 2005).

    • Word count: 2592
  2. Identification of reporter genes

    The following table shows what characteristics are expected from each reporter gene: Reporter Gene Characteristics under which condition LuxA-E genes Bioluminescence by leaving for 5-10mins in a dark room. LuxA and B genes Some Bioluminescence by addition of an exogenous aldehyde substrate then left in dark for 5-10mins. XylE gene Encodes for enzyme catechol 2,3 dioxygenase which turns catechol a yellow colour. lacZY In presence of inducer IPTG and substrate X-gal, bacterial colonies turn blue if �-galactosidase present One of the most typical uses of reporter genes is to learn about how a gene is regulated, typically a reporter gene

    • Word count: 2093
  3. Survival rates of micro-organisms

    The optimum growth temperature, commonly defined as the temperature at which most rapid multiplication occurs, is often only a few degrees below the maximum (Carpenter, 1972). These cardinal points allow bacteria to be classified according to their growth temperature: Psychrophiles are found in many lakes, streams and uncultivated soils, with their main principle being that they are able to grow at 0oC.Growth temperature ranges have been known to start from as low as -5oC and some facultative Psychrophiles still grow between 30 and 35oC (Carpenter, 1972).

    • Word count: 1417
  4. Microbes in Soil - Helping a Carbon Source or Sink?

    Approximately 50% of "typical" mineral topsoil comprises a mix of water and air-filled spaces that fluctuate according to prevailing environmental conditions whereas the other 50% is solid minerals and organic matters.[1] These hydrodynamic and atmospheric fluctuations result in a environment that drives the spatial and temporal heterogeneity of microbial diversity in soil and such interaction within and between the physical, chemical and biological components might cause the soil system to change over time [1]. Microorganisms in soils regulate the biochemical transformation in soil and are central to carbon (and nitrogen)

    • Word count: 1453
  5. Acute Myacardial Infarction

    The veins collect the blood from the capillaries, and the branches of the veins join to larger veins which deliver the blood back to the heart. The blood from the veins fill the heart as it relaxes during the interval between each contraction. The right side of the heart receives blood from the body and pumps it through the pulmonary artery to the lungs. There it picks up fresh oxygen and releases carbon dioxide. The left side of the heart receives oxygen-rich blood from the lungs, and pumps it through the aorta to the body (British Heart Foundation 2006).

    • Word count: 3247
  6. A review of positive and negative impacts of microbes on the environment

    They form the basis of the food chains, break down waste and recycle chemical elements such as nitrogen and phosphorus. Microbes such as unicellular algae have a role in photosynthesis, and many microbes live in the digestive of humans/ animals to aid digestion and synthesise certain vitamins. 'Biotechnology is the application of biological systems, organisms or processes in manufacturing or service industries...it is a composite science, involving microbiology, genetics, biochemistry and engineering', (Lowrie and Wells, 1994:38). Figure 1.2 shows the diversity of biotechnology Figure 1.2: Diversity of Biotechnology (Source: Madigan, et al, 2003: 6)

    • Word count: 3567
  7. bacterial leaching

    They only require a supply of Fe2+ ions or S2- ions, oxygen and carbon dioxide. The result of this process is that the copper ore separates out into its different elements. The solution contains Fe2+, Cu2+, Fe3+ and SO42- ions. Copper ions can be selectively removed from a bacterial leaching solution by a process called LIGAND EXCHANGE SOLVENT EXTRACTION. A ligand is a compound with a lone pair of electrons that binds to metal ions. A complex is formed in which the central mental ions are surrounded by a number of ligands. A good ligand compound for copper is mixed with an organic solvent, which is immiscible in water such as kerosene.

    • Word count: 1132
  8. The Effects of Varying Starch Concentration on a Solution of Amylase: Measurement of Enzymatic Rate Changes Using IKI.

    Enzymes achieve this by lowering the amount of activation energy needed for anabolic reactions, allowing these reactions to occur as catabolic reactions would. Enzymes are generally large proteins made up of several hundred amino acids, and often contain a non-proteinaceous group called the prosthetic group that is important in the actual catalysis. In an enzyme-catalyzed reaction, the substance to be acted upon, or substrate, binds to the active site of the enzyme. The enzyme and substrate are held together in an enzyme-substrate complex by hydrophobic bonds, hydrogen bonds, and ionic bonds (Nichols and Cholewiak, 1991).

    • Word count: 1232
  9. In this essay I will look at the biological significance of polysaccharides, and what makes them significant

    Polysaccharides have a general formula of Cn(H2O)n-1 where n is usually a large number between 200 and 500. Starch is a polysaccharide made up of alpha glucose monosaccharides. However the alpha glucose in starch forms two compounds; amylopectin and amlylose. Amylopectin makes up 70 % of starch, it consists of chains of glucose monomers linked with 1,4 glycosidic bonds. However about every 20-30 residus there is a 1,6 bond which results in branches being fromed. Amylose makes up the other 30% of starch, however it is an unbranched linear polymer unlike amylopectin. The monomers are joined in1,4 glycosidic bonds.

    • Word count: 631
  10. Permanent and Temporary Dipoles

    other molecules nearby, the instantaneous dipole may affect them and produce induced dipoles Induces Dipoles: * If an unpolarised molecule finds itself next to a dipole, the unpolarised molecule may get a dipole induced in it * The dipole attracts or repels electrons in the charge cloud of the unpolarised molecule, inducing a dipole in it * A dipole can also be induced by the effect of an instantaneous dipole - this makes it possible for a whole series of dipoles to be set up in a substance that contains no permanent dipoles Dipoles and Intermolecular Forces: * If a

    • Word count: 896
  11. Tiny Bubbles Biology Lab

    8. Fill the test tubes with tap water till the 3/4 mark and place them back in the stand. Experimental process: Part 1: 1. Using a tong, soak a felt disk in the yeast solution for 3 seconds. 2. While one person is in control of the felt, another lab partner must submerge the temperature probe into a test tube. 3. At the same time, a third lab partner must begin the LoggerPro program on the laptop by clicking COLLECT in order for the temperature probe to take temperature readings. In this trial, the temperature of the hydrogen peroxide will be at room temperature.

    • Word count: 2443
  12. Antibiotic Resistance

    Within a year however, a penicillin and methicillin resistant Staphylococcus aureus (MRSA) strain was described. Subsequently, vanomycin has been used in the fight against MRSA but recently vanomycin resistant S. Aureus (VRSA) have also been identified. Unlike MRSA, VRSA is not so widespread.1 S. Aureus is capable of causing a wide range of infections including skin and wound infections and bacteraemia, thus, untreatable MRSA infections pose a particular risk to the more immuno-compromised, such as critically ill patients.1 Unfortunately, we humans have contributed ourselves in making antibiotic resistance into a health risk.

    • Word count: 1252
  13. Enzymes - Competitive inhibition.

    But there is no oxidation so no speedy release of products. The inhibition is called competitive because if you increase the ratio of succinic to malonic acid in the mixture, you will gradually restore the rate of catalysis. At a 50:1 ratio, the two molecules compete on roughly equal terms for the binding (=catalytic) site on the enzyme. Link to a quantitative treatment of competitive inhibition. Enzyme cofactors Many enzymes require the presence of an additional, nonprotein, cofactor. * Some of these are metal ions such as Zn2+ (the cofactor for carbonic anhydrase), Cu2+, Mn2+, K+, and Na+.

    • Word count: 1337
  14. Macromolecules in Food

    This water bath is used in several activities. 2. 1 ml of apple juice and 3 ml of Benedict's solution are placed in a test tube, and a control is prepared. 3. The two tubes are placed in boiling water for 2-3 minutes. 4. The color of the solution is observed and note whether a precipitate has formed. 5. The test is repeated with coke, potatoes, onions and soy beans. Results are recorded. B) Starch Materials: * * Apple juice, coke, potatoes, onions, and soy beans * Test tubes * Iodine reagent Methods: 1.

    • Word count: 3088
  15. Relate the rates of evaporation of three liquids to the degree of intermolecular bonding within the liquid.

    As molecules absorb heat from their surroundings to evaporate, they also decrease the temperature of the surrounding because they absorbed all the heat energy. This means that evaporation is an endothermic process. So, when the most energetic molecules jump off into the air, the cooler molecules are left behind with less energy. All together, the surroundings become cooler during evaporation. That is why the thermometer gets cooler in the lab. So, the final temperature of the substances was less than the initial temperature since the most energetic molecules are gone.

    • Word count: 1837
  16. The aim of this experiment was to observe the movement of water molecules by the process of osmosis between living potato tissues and increasing amounts of glucose solution.

    The potato bore was used to bore 6 individual rods of potato. Each potato rod was separately cut into 5 pieces of 1.5cm long length and then these were weighted in groups of 5, (The weights recorded). The groups of 5 rods were then placed into the 6 different glucose solutions with the tweezers; H 0, 0.1 mole glucose, 0.2 mole glucose, 0.3 mole glucose, 0.4 mole glucose, 0.5 mole glucose. Each individual group of 5 rods were left in the different glucose solutions for approximately 2 hours. After the 2 hours each group of 5 rods were dried and weighted accordingly to their groups.

    • Word count: 905
  17. Urinary Tract Infections: The Pathogenic Traits of Proteus mirabilis.

    2. Morphology Cell morphology was investigated by inoculating the centre of a nutrient agar (NA) plate, and some nutrient broth (NB) with a colony from the CLED plate and examining cells from the plates under the electron microscope. 3. Chemotaxis a) Chemotaxis chamber: One well and half of the channel was filled with 10% nutrient agar. The opposite well and the rest of the channel were filled with 1M hydrochloric acid. This was repeated in other chambers substituting 1M HCl with either 1M potassium hydroxide, 1M glucose or sterilised distilled water (SDW).

    • Word count: 2107
  18. Describe the chemotaxis systems of bacteria.

    The fine structure of the flagellum is that of a right-handed helical fibre embedded in the bacterial cell membrane. It is composed of multiple repeats of a single type of protein subunit called Flagellin. A single bacterial cell may possess multiple flagella. The bacterial flagellum sits between the inner and outer membranes of the bacterium, and has a number of distinct components. Rotation of the flagellum follows as a direct result of its structure. The fibre is connected by a short flexible protein hook to a small protein disc embedded in the plasma membrane. This disc constitutes part of the motor, and by utilising the energy stored in the transmembrane proton gradient, the bacterium can cause this disc to rotate, thereby effecting movement of the fibre.

    • Word count: 2405
  19. The discovery of sulphonamides.

    Their findings were confirmed by Fuller, in which sulphanilamide was isolated from the blood and urine of patients treated with Protosil (Fullerton, 1998). Following the dramatic success of Protosil, a cascade of sulphanilamide derivatives began to be synthesised and tested, by 1948 more than 4500 existed, but only about two dozen actually have been used in clinical practice. The sulpha drugs have proven to be ineffective against certain infections such as Salmonella (Patrick, 2001).

    • Word count: 598
  20. What are Cytotoxic T Lymphocytes?

    * CD8+ T cells bind epitopes that are part of class I histocompatibility molecules. Almost all the cells of the body express class I molecules. * CD4+ T cells bind epitopes that are part of class II histocompatibility molecules. Only specialized antigen-presenting cells express class II molecules. These include:dendritic cells, phagocytic cells like macrophages and B cells! CD8+ T cells The best understood CD8+ T cells are cytotoxic T lymphocytes (CTLs). They secrete molecules that destroy the cell to which they have bound.

    • Word count: 648
  21. Effect Of An Inhibitor Such As Copper Sulphate On The Activity Of Catalase

    The more H2O2 molecules there are, the less likely is it that CuSO4 (inhibitor) molecules will bind with active site. This is because I expect CuSO4 to either inhibit or inactivate the catalytic activities of Catalase. Biological Principal Enzymes are biological catalysts that make possible chemical changes under the condition in cells. They are globular proteins and are coiled into a precise, three-dimensional shape, with hydrophilic R groups on the side of the molecules enabling them to be lobule in water. Enzymes work by binding to their substrate molecules at their active site, as the enzyme (E)

    • Word count: 1041
  22. Penicillin Enrichment of Listeria monocytogenes pathogenicity mutants.

    Once in the cytoplasm of the host cell the bacteria replicates and concomitantly becomes covered in host actin filaments. When the actin polymerises at the base of the actin 'tail' the bacteria is propelled to the edge of the host cell. Once at the cells' edge the bacteria protrude from the surface forming pseudopods. These are in turn recognised by neighbouring cells and the bacterium is internalised. The bacterium this time is internalised into a double membraned vacuole. These membranes are lysed by another pore-forming protein, phospholipase C (PLC), and the cycle begins again (adapted from Cossart and Lecuit, 1998).

    • Word count: 4855
  23. The Effect of copper sulphate on the activity of catalase.

    Variables In this experiment, the variable that is measured- the "dependent variable" is the volume of oxygen evolved which is an indication of the activity of catalase in the reaction. The variables which have an effect on the amount of oxygen evolved- the "independent variables" are: * Volume of hydrogen peroxide * Presence of copper sulphate * Time Other factors which are not necessary for the experiment- confounding variables but will have an effect on the dependent variable (volume of oxygen evolved)

    • Word count: 5590
  24. Observe the effect of temperature on activity of the enzyme amylase.

    The peak activity will be around 40oC. The activity will fall sharply above 40oC. Apparatus 0.5 % starch buffered to pH 6.7 1% NaCl solution Fearons reagent 20% NaOH solution pH 6.7 buffer Amylase solution Distilled water Tongs Boiling tubes Boiling tube rack 100 cm3 measuring cylinder 1, 5 and 10 cm3 pipettes and safety pumps Gloves Goggles Cuvettes Stop clock Colorimeter Ice Bath (0 oC), Water baths Bunsen burner Tripod Gauze Heatproof Mat Safety * Lab coat (protect clothes) * Safety goggles (protective eye care) * Rubber gloves (protect hands. 20% NaOH is a corrosive irritant)

    • Word count: 961
  25. Microbial Evaluation of Two Food samples (Chicken and Doubles) Aim: To identify and count different bacteria present in chicken and doubles (Salmonella, Staphylococcus, E. coli, and total aerobic bacteria).

    The isolated colonies for enumeration will grow along the lines of the streaks. Salmonella, Staphylococcus and E. coli (enterovirulent) are some of the most common and dangerous microbial food borne organisms. Salmonella frequently has been associated with food borne illnesses and cause salmonellosis. Symptoms may include nausea, fever vomiting and acute gastroenteritis. Staphylococcus species such as S. aureus is also another principal causative agent in food borne illnesses. It grows in food and produces toxins that, when ingested causes an inflammation of the lining of the stomach and intestinal tract, or gastroenteritis. E. coli is mostly found on the surface of meats.

    • Word count: 2668

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