Effect of refrigeration and covering of mayonnaise on the growth of bacteria.
Abstract.
Growth is characteristic feature of life; this simply means the regulated and coordinated enlargement in biological mass over time. Bacterial growth involves division of one cell of the bacteria into two cells in a process known as binary fission. Specific conditions are required for the survival of bacteria. Most bacteria require environments that are moderate, suitable and assure optimum growth. The common conditions that need to be set include temperature, oxygen concentration, nutrients, salt concentration and pH. Different bacterial species have to be well examined to allow bacterial growth in an artificial lab condition. Optimum oxygen levels and aeration
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The study of bacterial growth kinetics by pioneer Jacques Monod demonstrated the relationship between bacterial growth and limiting nutrient concentrations. He demonstrated that bacterial growth is linearly dependent on initial concentration of the limiting nutrient. He also mathematically incorporated this relation in the exponential bacterial growth equation and was able to come up with a model similar to the Michaelis-Mention representation of enzyme kinetics for the relationship between concentration of the limiting nutrient and growth …show more content…
The constant factors in the experiment included; temperature in the refrigerator remained unaltered and also the temperature in the room was allowed to remain constant. Other constant factors were: mayonnaise came from the same jar; the time that the mayonnaise was left unrefrigerated was the same and sample sizes of mayonnaise were measured. Our experimental group (group of any experiment that receives the treatments being tested, one treatment is tested at a time and the group is compared to the control group) was the one that was tested by changing the independent variable(s) for our case the refrigeration and cover or the lid of the jar. We made the group larger so as to arrive at definitive results. Our independent variables (variables whose variation does not depend on that of the other) in the entire experiment were the lid, the cover or the state of being covered and uncovered and the state of being refrigerated or not. From this simple design of our experiment we anticipated to see microbial growth first displayed from the lack of refrigeration as well as more increased growth by being exposed to the open air. The dependent variable (variable whose variation depends on that of the other variables) was the final state of
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
The [ES] complex can then undergo two different pathways; the complex can dissociate to [E] and [S], at a rate of k or it can shift equilibrium to the left with a rate constant of k2 to form [E] and product [P]1. In this model, the breakdown of the ES complex to yield P is the overall rate-limiting step. Three assumptions of a Michaelis-Menton plot are that a specific [ES] complex in rapid equilibrium between [E] and [S] is a necessary intermediate, the amount of substrate is more than the amount of enzyme so the [S] remains constant, and that this plot follows steady state assumptions. Steady state assumptions states that the intermediate stays the same concentration even if the starting materials and products are constantly changing.2 The rapid equilibrium between enzyme and substrate, and the enzyme-substrate complex yields a mathematical description regarded as the Michaelis-Menton
Going into details of the article, I realized that the necessary information needed to evaluate the experimental procedures were not included. However, when conducting an experiment, the independent and dependent variable are to be studied before giving a final conclusion.
One of the greatest accomplishments and innovations of human history thus far is the invention of the electric refrigerator. Such a simple concept has literally changed how the entire world stores food and has saved millions of lives in the process. Refrigeration as we know it has only been around since the 1930’s, and in less then a hundred years has been greatly taken for granted. Since the influence of electrical engineering in the modern refrigerator, refrigeration has gone from storing food in an ice cellar to being able to have two dedicating refrigeration units with controllable temperatures and even an ice machine attached. Without electricity modern refrigeration would be drastically different, using instead previous refrigeration
The purpose of the lab was to show the effect of temperature on the rate of
In our Biology Lab we did a laboratory experiment on fermentation, alcohol fermentation to be exact. Alcohol fermentation is a type of fermentation that produces the alcohol ethanol and CO2. In the experiment we estimated the rate of alcohol fermentation by measuring the rate of CO2 production. Both glycolysis and fermentation consist of a series of chemical reactions, each of which is catalyzed by a specific enzyme. Two of the tables substituted some of the solution glucose for two different types of solutions. They are as followed, Table #5 substituted glucose for sucrose and Table #6 substituted the glucose for pH4. The equation for alcohol fermentation consists of 6 Carbons 12 Hydrogens 6 Oxygen to produce 2 pyruvates plus 2 ATP then finally the final reaction will be 2 CO2 plus Ethanol. In the class our controlled numbers were at Table #1; their table had 15 mL Glucose, 10 mL RO water, and 10 mL of yeast which then they placed in an incubator at 37 degrees Celsius. We each then measured our own table’s fermentation flasks every 15 mins for an hour to compare to Table #1’s controlled numbers. At
As different strains exhibit various growth morphotyes, the combination of different culture media (at least two of them) should be used to achieve optimal recovery rates. This is further increased if transport time is minimized, and if specimens are kept at 4 °C at all times during transit.
Refrigeration Refrigeration is defined as “The process of removing heat from an enclosed space, or from a substance, to lower its pressure.” (First website given in bibliography) In simpler terms, it is removing heat from states of matter in order to keep them cooler. The basic need for refrigeration is to cool food and beverages, as they often get spoilt if the temperature is high. Before actual refrigerators and other such mechanical systems were introduced, it was very common for people to cool their food with ice and snow.
Control conditions are crucial in this experiment because there needs to be two different groups to test the hypothesis; a control group and an experimental group. The two groups
Dependent Variables Amount of vitamin C in fruit juices. Controlled Variable Same amount of liquid for each fruit juice.... ... middle of paper ... ...
In our experiment, we are testing the affects sodium has on our blood pressure. If increased amounts of sodium are consumed, will that increase blood pressure? The hypothesis is when more sodium is introduced and consumed, then the person's blood pressure will increase, when blood pressure is a function of sodium. Our independent variable is different amounts of sodium introduced to noodles. We are using different amounts of sodium added which would be: 1 gram, 3 grams, 5 grams, and 7 grams. Our dependent variable is the diastolic and systolic readings will increase. The control in our experiment is our test subjects eating no noodles. The constants would be the same person taking the blood pressure, same three guys eating the food, the test subjects are all 17, and the same food with added sodium fed to each person in each trial. In this experiment, the first step we would took in this was acquiring three guys that are all 17 . One person would get high amounts of sodium, another person would have medium, and one person with very low amounts of sodium, our control. Then, we would take each person blood pressure and record it. After that we would give each person their assigned amount of sodium. Lastly, we would take the blood pressure of each person after they ate the different sodium foods. We will do this for two weeks three times a week and record our data and at the end compare our data. The materials we will need
Bacteria are single celled microbes. Bacteria reproduce by binary fission. In this process, the bacterium, which is a single cell, divides into two identical daughter cells. Binary
Independent variables: The temperature of hcl gas will be decreased and increased throughout the experiment.
In this paper, the discussions focus on the purpose, advantages, and disadvantages of conducting experimental designs, importance of internal and external validity claims, define what is/are control, control groups, confound, cause, and how correlation and causation are related. Finally, concluding with specific questions identified for this assignment.
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.