factors affecting saccharomyces cerevisiae

factors affecting saccharomyces cerevisiaeChapter 1 Introduction investigate QuestionsWhat is the effect of differing temperatures on genus genus Saccharomyces cerevisiae population yield?What is the effect of differing pH levels on Saccharomyces cerevisiae population growth?What is the effect of differing glucose concentrations on Saccharomyces cerevisiae population growth?The yeastSaccharomyces cerevisiae is a single celled fungus that reproduces asexually by budding or division. It is one of the most well pukevas eukaryotic model organisms in both molecular and cell biology.S. cerevisiae is a actually goodly type of yeast for biological studies owing to the fast growth (doubling time 1.5-2 hours at 30 C), the dispersed cells and the ease of breeding planting. Moreover is a non-pathogenic organism, so undersurface be handled fearlessly with hardly little precautions. alike large amounts of commercial bakers yeast be getable with reply being an easy and cheap source for biochemical studies.S. cerevisiae has calendar method to ovoid cells amongst 3-8m in diameter.1.2 ventilation systemIn biology, external ventilating system is defined as the process by which the muscle in fare molecules is made available for an organism to do biological work (Kent, 2000 p.100). It is in any case called Cellular ventilation. This process of cellular respiration happens in every animate cell as it is the only way to obtain energy in a form that will be usable for the cell, so it can move out the functions of movement, growth and reproduction (ibid).The food in yeasts essential be obtained as they cannot produce it on their own. For yeasts, a very good source of energy is sugars. All strains of S. cerevisiae can metabolize glucose (a hexose sugar), maltose and trehalose.1.3 Types of RespirationThere are two main types of respiration that take patch in spite of appearance a cell Anaerobic respiration (without oxygen) and Aerobic respiration (with oxygen). S. cerevisiae can metabolize sugars in both ways, but in this look into the cultures of yeast were exposed to air hence to oxygen, so aerobic respiration was generally the way that yeast cells grew and reproduced.1.4 EnzymesThousands of chemical answers are carried out within a cell. These reactions most of the times occur in a very slow graze. For that reason living organisms make biological catalysts which are called enzymes and pep pill up these reactions. Enzymes are globular proteins which act as catalysts of chemical reactions (Allot, 2007 p.18. Also cells can control which reaction occurs in their cytoplasm by do some enzymes and not others. Enzymes achieve to increase the charge per unit of a reaction by decreasing the activation energy (the minimum amount of energy required for a reaction to occur) (Greenwood. Et al. 2007 p.167) of the subst compute or the subst esteems, when binding to the activation site (Greenwood. et al. 2007 p.114).Enzymes are sensitive molecul es with very specific structure which enables them to carry out specific reactions. This structure including the expeditious site can be damaged by various conditions and substrates. This damage is called denaturation and is usually permanent for an enzyme and if denaturation is occurred the enzyme can no perennial carry out its function. As a conduce when enzymes are required to catalyze a reaction, is necessary that they have suspend conditions. Different enzymes have different ideal conditions called optimum. The factors that affect the enzyme action at law are the temperature, the pH, the substrate concentration.The effect of temperature, pH and substrate concentration upon the enzyme activity which affects the growth of S. cerevisiae yeast cells are studied in this research.1.5 Effect of TemperatureAs the temperature is increase in an enzyme-catalysed reaction, the rate of reaction is increased up to maximum in a specific temperature. This is called optimum temperature. Th e optimum temperature of Saccharomyces cerevisiae is 30o- 32oC. above this temperature the rate starts to drop rapidly. This is due to the steep energy that causes vibration inside the enzyme with result the bonds which maintain the structure of enzyme to break. This causes denaturation and the active site can no longer fit the substrate.1.6 Effect of pH (hydrogen ion concentration)Most of the enzymes operate effectively in a small range of pH determine. Between these pH values there is an optimum pH value in which the enzyme activity is the highest. The optimum pH of Saccharomyces cerevisiae is 5.5. Acids and alkalis cause denaturation of the structure of the enzyme by breaking mainly hydrogen and ionic bonds with result the substrate cant fit the active site. Furthermore the charges of the amino acids within the active site are touched by pH changes, so the enzyme is not able to form an enzyme-substrate complex. Above and below the optimum pH the enzymatic activity hence the rat e is reduced considerably.1.7 Effect of Substrate concentrationIn an enzyme-catalysed reaction the rate increases in direct proportion to the substrate concentration. The optimum glucose concentration of Saccharomyces cerevisiae is 2%. At low substrate concentrations, the rate of enzymatic activity increases sharply as the substrate increases. This occurs due to the more frequent collisions between the substrate molecules and the unoccupied active sites. On the other hand, at high substrate concentrations the biggest part of the active sites have been occupied with result when increase the substrate concentration there is little effect on the rate of enzymatic activity.1.8 Purpose of the researchThe purpose of this research that is carried out to look the growth of S. cerevisiae yeast cells in different factors and various conditions is not so in order to discover which are the optimum conditions in from each one factor (as this species of S. cerevisiae is very well studied and ex amined professionally because of its usage in food industry) but to examine in real conditions and not supposititious ones how altering the environment of a cell affects the way its enzymes work and wait on the whole cell to live and divide in all of the antecedently ways that were mentioned in the introduction part.