Combo with all Lab Report Questions With Complete Solutions

Why is the catalytic activity of enzymes essential to ensure and regulate cellular metabolism? correct answer: enzymes lower the activation energy for chemical rxn. Why are microorganisms able to cause diary products, such as milk, to sour or curdle? correct answer: microorganisms can break down the nutrients in the milk and cause it to sour or curdle. Give a reason why it is necessary for polysaccharides, such as starch or cellulose, to be digested outside of the cell even though di-saccharides such as lactose or sucrose, are digestible inside the cell. correct answer: The polysaccharides are large sizes, high molecular weight nutrients, highly complex molecules of carbohydrates and are not capable of permeating the cell membrane. The disaccharides are comparatively simpler as they are units of two monosaccharides and hence can be digested inside the cell. It is simpler to make the disaccharides to monomeric form. Discuss the medical significance of the IMViC series of tests correct answer: Using the IMViC test will determine the biochemical properties and enzymatic reactions of enterobacteriaeceae. The IMViC will determine whether they are pathogenic, occasional pathogenic, or normal intestinal flora Explain the chemical mechanism for detecting indole in a bacterial culture correct answer: The presence of indole is detected by adding Kovac's reagent, which produces a cherry red reagent layer. The enzyme trytophanase breakdown trytophan into indole, pyruvic acid and ammonia. Account for the development of alkalinity in cultures capable of using citrate as their sole carbon source. correct answer: The carbon dioxide generates and combines with sodium and water to form sodium carbonate which is alkaline. In the carbohydrate fermentation test, we found that both E. coli and E. aerogenes produced the end products acid and gas. Account for the fact that E. coli is methyl red-positive and E. aerogenes is methyl red-negative. correct answer: Both of these organisms initially produce organic acid end products during the early incubation period. The low acidic pH of 4 is stabilized and maintained by E. coli at the end of incubation. During the later incubation period, E. aerogenes enzymatically converts these acids to non-acidic end products such as 2,3-butanediol and acetone, resulting in an elevated pH of approximately 6. The end products of tryptophan are indole and pyruvic acid. Why do we test for the presence of indole rather than pyruvic acid as the indicator of tryptophanse activity? correct answer: