Mannitol Agar Lab Report

The importance of identification of a certain microorganisms can range between a life threatening diseases to a creation of certain antibiotic. Understanding the principals of living microbes and identifying my unknown bacteria through numerous biochemical and metabolism tests, with the outmost confidence, Proteus vulgaris had the precise qualifications. The point of this report is to further explore the identification of my unknown bacteria by revealing the results of the experiments and comparing them to the other six known bacteria: Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Alcaligenes faecalis, Escherichia coli, and Proteus vulgaris that were used in the lab, as well as comparing and

For the final test, two drops of hydrogen peroxide (H2O2) were placed on the isolated colony of the BHIA medium, observed immediate formation of bubbles, as O2 was produced indicating a positive test for catalase.

In the LB (pGLO negative), it is expected to not see any colonies growing. As a result of this experiment, it shown any growth colonies but this only had shown a large number of white, circular colonies that were found across the surface of the agar. In the LB/Amp (pGLO negative), it is expected to see any growth colonies. In the experiment, the resulted was no growth colonies because this has Ampicillin and no pGLO. Now, the LB/Amp (pGLO positive), it is expected to have growth colonies in the agar plate. As a result, it was shown growth colonies in the agar plate because has positive pGLO regardless having Ampicillin. In the other hand, both positive pGLO have the same components but in one plate was added Arabinose. The LB/Amp/Ara (pGLO

The identification of unknown organisms carries important ramifications that can be applied to many real world scenarios. In keeping with quality assurance beverages, food, cosmetics, and other products are frequently inspected for contaminants resulting from a presence of pathogenic bacteria. In medicine, a physician’s diagnosis and consequent treatment is largely determined from samples collected from infection sites that have been analyzed using microbial tests.

The alternative, no bubbles produced, meant a catalase negative organism. For oxidase, as stated in the lab manual, a sterile toothpick was used to obtain growth from the quadrant streak and placed onto a paper strip. This test will show a color change for organisms that produce cytochrome

Research Question: How does the size of the cell affect its efficiency in exchanging substances through several ways, like diffusion?

When determining which bacteria I wanted to use for this experiment I had to decide on E.coli bacteria which is gram negative and staphylococcus a gram positive bacterium. These were chosen because they are safe enough to grow in a college laboratory and were supplied by the technician. Gram negative bacteria has an outer membrane making it more resistant to antiseptics and antibiotics, it also makes it more fatal to the human host it is inhabiting. Whereas gram

The purpose of this investigation is to discover the effect of pH on the activity of catalase, an enzyme which plays the integral role of converting hydrogen peroxide into water and oxygen, and discover which pH level it will work at the most efficient rate (the optimum). The original hypothesis states that that the optimum would be at a pH is 7, due to the liver, where catalase usually resides, being neutral. The experiment consists of introducing the catalase to hydrogen peroxide, after exposure to certain solutions; hydrogen peroxide, water and hydrochloric acids, all containing the adjusted pH, and measuring the height of froth formed, an observable representation of the activity of the enzyme. The final data indicated that

Each test performed in the lab on theses unknown bacteria have a very specific significance. With each test performed correctly the lab officer is able to move closer towards a proper identification of the unknown bacteria. After performing Gram staining and deciphering if the unknown was gram positive or negative the lab officer was then able to proceed to the next step of identification. The gram positive unknown’s reaction to the catalase test informs the tester of the Genus theyre working with. This indicates which tests to perform next. The MacConkey agar is a selective medium that only allows the growth of gram positive bacteria confirming the results received from the gram staining procedure. The NaCl growth test indicates whether or not the organism is able to

The chemical hydrogen peroxide(H₂O₂) is broken down by the enzyme catalase. Hydrogen peroxide is a byproduct formed in cellular reactions that, if not broken down, could inflict severe damage to the cell. Catalase is an enzyme that breaks down hydrogen peroxide in to water and oxygen. How efficient and strong the enzymes reaction to break down H₂O₂ determines largely on temperature and pH level. An enzyme only functions within a set pH and temperature range. Beyond that it becomes denatured, rendering it useless. The purpose of this lab is to determine at which temperature and pH level the enzyme catalase reacts best. Catalase in chicken and beef livers will be used to do the lab because enzymes still function after death as long as they are kept refrigerated at a low temperature.

Hydrogen peroxide is a toxic byproduct of cellular functions. To maintain hydrogen peroxide levels the catalase enzyme deconstructs hydrogen peroxide and reconstructs the reactants into oxygen gas and water. The catalase enzyme is found inside cells of most plants and animals. Regulating the levels of hydrogen peroxide is crucial in homeostasis and analyzing it’s optimal conditions for performance is just as important. To understand the optimal environment for this enzyme, they are put into different environments based off protein activity (enzymes are proteins). Catalase samples will be put into different hydrogen peroxide environments based off pH and temperature. The more active the enzyme, the more oxygen and water it will produce. Enzyme activity can be seen through the release of oxygen in the hydrogen peroxide. Since oxygen cannot be accurately measured, the data will consist of the longevity of the reaction in different environments. If the pH is higher than 7, then the reaction rate will increase due to the ample amount of hydrogen ions in the hydrogen peroxide. However the pH level cannot be higher than 10 or else there will be too many hydrogen atoms in the peroxide for the enzyme to be able to deconstruct them. If the temperature is increased, then the reaction rate will increase due to the ample amount of energy and movement in the hydrogen peroxide and enzyme.

Background Information An enzyme is a “macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction,” (Campbell Biology, 68). There are many different enzymes that have varying effects on reactions. Catalase, “an enzyme that brings about (catalyzes) the reaction by which hydrogen peroxide is decomposed to water and oxygen,” is the primary enzyme that effects hydrogen (Encyclopedia Britannica). In this experiment, the goal is to test how three different locations where these enzymes can be found catalyze the reactions in hydrogen peroxide. When hydrogen peroxide is exposed to certain enzymes it starts to become water due to the loss of oxygen molecules.

|MSA Agar |For organisms that are |Isolates for mannitol fermentation |Yellow color change in |Staphylococcus aureus |

Catalase breakdown hydrogen peroxide into water and oxygen. This experiment was to test the reaction on catalytic activity

Changes in enzymes can make bacteria immune to the antibiotic it’s fighting. Agar is like a fertilizer for the bacteria to grow and nourish off of. (Lerner 2007) Using sheep blood agar, one study used ultraviolet radiation on antibiotic resistant bacterial strains of Staphylococcus and Enterococcus. The antibiotic resistant bacteria were completely killed off within 120 seconds by the radiation. (“The effects