Low Nutrient Experiment

Background information: In this lab you will be looking at the growth of bacteria under different conditions to see the how populations of bacteria grow. Read about cells in the text or e-text. For everyone, in your e-text read chapter 13, sections 13.3 and 13.4 to learn more about bacteria. Then answer the questions below.

For an existing habitat, an increase in salt levels will begin to show an effect on the abundance and diversity in species of zooplankton. This will exhibit a detrimental effect on the daphnia from the limited osmoregulatory capabilities of the organisms. This in turn can pose a risk to the level feeding rates and survival (Heine-Fuster, Vega-Retter, Sabat & Ramos-Jiliberto,

This experiment is about bacterial growth. We will demonstrate a bacterial growth curve using a closed system. Bacterial growth usually takes up to 12-24 hours to get an accurate result so we will be monitoring this growth between two classes. We also used different methods to determine bacterial growth as well as a few different calculations. One way of receiving data is by using a spectrophotometer where we will record the absorption at a given time to create the bacterial growth curve. We also used the plate count method after performing a serial dilution to calculate the actual cell density at different times given. By using this method we can count the population number of the same given and see the maximum cell density

As shown in the figure above, it is evident that V.natriegens grew faster when the Brain Heart Infusion (BHI) broth contained 250mM NaCl. The # of bacterial cells at each time point was measured following the equation given in the “How to generate a bacterial growth curve” supplemental material posted on D2L. (2) The data was then recorded in the table listed above. A growth curve graph was constructed using the data above which illustrated the differences between each of the different BHI mixtures. The graph was then used to determine the generation time of V.natriegens for each different environmental condition. In order to calculate the generation time (g) the mean growth rate (k) must be calculated. The formula to do this is posted in the supplemental material “How to generate a bacterial growth curve” on D2L. The k value calculated for each condition goes as follows:

[01.03]Sue conducts a series of experiments to investigate the effects of UV radiation on bacteria growth. In order to verify and strengthen her findings, she asks another scientist to conduct the same experiments in an independent investigation. The results of the second investigation are expected to be

Microbe growth can be influenced in a number of ways. One influence is pH. Most bacteria thrive around pH values that are neutral, although some can grow in extremely acidic environments (Blamire, 2000). Nutrient availability can also have an impact on microbial growth. Nutrients can

We hypothesized that there is no correlation between nutrient availability and the maximum growth rate and the carrying capacity. Based on our results about we concluded to reject our hypothesis since nutrient availability does affect growth rate and carrying capacity of the species.

We can measure how certain variables like temperature, ph and oxygen levels affect on biological processes such a growth rate, reproduction and mortality. The organism we choose to study can be from different trophic levels to see how these changes affect the ecosystem as a whole and the food web. We can take measurements of these factors where they are high and see how they affect the organism. Additionally, we can test these variables individually in close systems to see what type of effects it has. In a video we watched in class we saw how rising pH could affect corals killing them off with coral bleaching and if acidic enough the coral itself would erode away because it was under the saturated state. Understanding these effects is essential to preserving our ocean and its

The purpose of the scientists performing the pGLO lab was to see if they were able to alter the DNA of a bacteria, E. coli, causing the bacteria to glow, if the insertion of the glow gene, which originated in a jellyfish, was successful. Four groups of bacteria were experimented with. Two of these groups were control groups; the bacteria with no DNA alteration on an agar plate containing nutrient broth, and the bacteria with the pGLO gene added on an agar plate with both Ampicillin and nutrient broth added to it. Each of these plates acted as a baseline for comparison for the other two plates, which were the experimental plates. The experimental groups were the groups consisting of unaltered bacteria on an agar plate containing Ampicillin and nutrient broth, and the altered (pGLO gene added) bacteria on an agar plate containing the nutrient broth, Ampicillin, and Arabinose sugar. Along with control groups and experimental groups, every experiment has both independent and dependent variables. In the pGLO experiment, the independent variables were the Ampicillin, Arabinose sugar, and the nutrient broth, all of which were added to the agar plate, as well as the pGLO gene being added to the bacteria’s DNA. These

Alyssa E. Beck conducted an experiment in which her purpose was to observe the effects of short term ultraviolet light exposure on bacteria. In this experiment, she placed and labeled bacteria samples onto plates and exposed the bacteria to ultraviolet light for two, five, and thirty minutes. For each sample, half of the plate was exposed to the ultraviolet light while half was not, serving as the control group. The results of the experiment showed the bacteria not exposed to the uv light grew into distinct colonies while the none of the exposed bacteria survived after the time periods (Beck

In this lab experiment, students had to create a growth curve for E. coli. The E. coli growth curve would illustrate the progression of the population of E. coli a set time period. In this case, the growth curve depicted the population of E. coli over a 12-hour period. The growth curve for E. coli was created from the absorbance levels, the optical density(OD), recorded from the spectrophotometer.

Plankton are aquatic organisms that drift throughout their environment as they posses no true motor capabilities. Within their respective aquatic habitats plankton form the productive basis of their ecosystem and are divided into two subcategories: zooplankton and phytoplankton, the later will be the primary focus of this paper. Phytoplankton, as well as other photosynthetic organisms poses pigments called chlorophyll. These pigments allow phytoplankton to convert carbon dioxide and water to oxygen and sugar, which provides the phytoplankton with energy. Due to the fact that all phytoplankton posses chlorophyll scientists have developed methods that use chlorophyll testing in order to understand more about phytoplankton as a whole. Phytoplankton posses different types of chlorophyll but scientists usually sample chlorophyll-a as it is the most abundant form (YSI Environmental, Cullen 1982, Santos 2003). Several different methods have been developed to analyze the concentration of chlorophyll-a.

After looking at the results of this lab, we noticed that the growth in the first Nutrient agar plate had a multiple bacterial growth, but for the sabouraud dextrose had variety of fungus which means that the fungi grow isolated from other microorganism in the soil. For the second Nutrient agar plate we saw a clearing on the 4 areas that we added the soil on which means that the fungus had produced the antibiotic (penicillin) to inhibit and kill the other microorganisms.

This experiment was performed to test the hypothesis if LB nutrient broth, +pGLO and -pGLO Ampicillin, and Arabinose was placed in the E. coli plates, then there will be a significant growth in the newly transformed bacteria and it will possess the ability to glow under UV light. The measurements were recorded from the bent glass tube in each glass test tube. The transformation protocol tested for the newly possessed traits in E.coli bacteria. Throughout the experiment there were many probable reasons for failure. If the pipettes and sterile loop were not thrown out in between each use, a cross contamination could cause a miscalculation in the experiment causing the data results to fail. The hypothesis that was tested was validated due to the positive results with each experiment stating that newly transformed organisms due in fact pass on traits.

THEORY: Nutrient agar media is used to facilitate the growth of the wide range of non-fastidious bacteria.