Closed Growth Curve Lab Report Essay

When the pH is not at its optimum, the differing pH's will disrupt the bonding between the R groups of the amino acid causing its structure and the shape of the activation site to change

The conditions needed for the growth of micro-organisms are: Micro - organisms need food to survive. They like high protein food to survive, eg. Poultry & fish. Most micro - organisms need warmth & grow best at 20-40c. They need moisture to multiply. They need air to multiply, though some can without. A single Micro-organism becomes two every twenty minutes.

All bacteria need time to be able to multiply and it has been observed that generally bacteria divide into two every twenty minutes.

---If given traits and parents, be able to use a Punnett square or patterns to predict the probability of offspring for a given cross and express it as a fraction, percent, or ratio.---

Many tests were completed on the unknown such as gram staining and inspection under microscopes to find whether the bacterium is gram positive or gram negative. Chemical resistance tests were also performed to see if certain chemicals affected the unknown growth or if it didn’t affect the bacteria at all. Each biochemical test

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.

this means that is the optimal temperature, but in bacterial occur in less time than in fungal

Bacteria are small, unicellular prokaryotic microbes. They have many morphologies, which include rod-shaped, spherical, spirals, helices, stars, cubes, and clubs. Classification of bacteria begins with either aerobic (requiring diatomic oxygen for growth) or anaerobic (not requiring O2 for growth). Bacteria can simply be narrowed down to gram positive (organism that stains purple or blue by Gram stain) or gram negative (organism that stains red or pink by Gram stain). Many physical and nutritional factors influence bacterial growth. Physical factors include temperature (psychrophiles, thermophiles, and mesophiles), pH (neutrophiles, acidophiles, and alkalinophiles), O2 concentration (aerobic

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:

The lag phase is when the organisms are first place into a new medium and will take time to get used the their new environment. During this phase, organisms will grow in size but cannot replicate. The next phase is the log phase. In this phase cells are dividing and growing at a very fast rate. DNA replication begins in this phase as well as their metabolic rate starts to increase rapidly. (Bacterial Growth Curve) Cells divide by binary fission. The organisms will eventually reach maximum growth and start to level off beginning the next phase, the stationary phase. In this phase, the bacterial population will start to slow down and stop dividing because the nutrients needed for them to grow are being used up. The pH and temperatures start to shift making the environment and unfavorable one and the accumulation of waste and toxic metabolites the growth starts to die off, transitioning into the last and final stage. (Bacterial Growth Curve) The death phase is when there is longer any nutrients to grow and to much waste has built up along with toxic materials, killing the cells. However, some organisms can withstand this environment and begin to produce endospores. (Bacterial Growth Curve)

Early studies have documented that bacterial growth increases in space flight; yet, the inherent mechanisms beholden to this growth have not been discovered. As the bacteria devour nutrients, they discharge corollary that can affect growth and impact ultimate cell population denseness. It is acknowledged that these metabolic processes charge a reduction in density of the fluid zone and the solute gradient about every cell. Along this planet, this fluctuation in density leads to an elasticity transfer of the expelled by-products. The fluid motion enclosing the cells can be changed through the restricting of the movement to just diffusion because of the lack of activity and deposit in the low-gravity space flight surroundings. From this biophysical representation, it was speculated that an increase in speed impacts the lag phase period and the final cell 's denseness of suspended cultures of bacteria in a deviating way. This is because of the modifications obtained in the extra cellular fluid constitution. Contained in the paper are experiments of different accelerations that frequently sustained this hypothesis, culmination in foreseeable growth kinetics. Other experiments show plumes of fluid that are visible to the naked eye emerging from metabolizing bacterial cultures. If related fluid kinetics were discovered to come about on a microscopic level, it might inform us of how acceleration impacts bacterium growth kinetics.

During the lag phase there is no increase in cell numbers, although the bacteria are synthesizing enzymes present in their environment in preparation for the exponential phase. During the exponential or logarithmic phase, the bacterial population grows at a rate that doubles the population during the generation time. The stationary phase incurs neither an increase nor a decrease in the cell population. The population growth cannot continue at the exponential rate since the nutrient supplies have been depleted and waste products have accumulated. The final phase of the bacterial population growth curve is the death phase, during which more cells die than are replaced by new cells.

Being able to control bacterial growth is something that is important in our everyday lives. As shown in the previous labs, bacteria can grow and create colonies extremely quickly especially in the right environments. By acknowledging this, it is then important to get an understanding of how bacterial growth can be controlled by humans. To control microorganisms it means to inhibit their growth (static) and or kill them (cidal) (Kenneth Todar, 2015); therefore since focusing on bacteria the terms bactericidal and bacteriostatic are both extremely important for this lab. One broad method we will use to control bacterial growth is heat. The amount of heat needed to control bacterial growth is different for different species of bacteria (Kenneth Todar, 2015). Bacteria can also respond differently depending if moist heating method such as an autoclave with steam is used, or a dry heating method such as inoculating a loop over a fire is used (Kenneth Todar, 2015). UV works by damaging the cells DNA, without proper DNA, the cells will die and the object

There is no “home stretch” just the passing of another chapter in working towards goals. 

These ranges are classed as cardinal temperatures and consist of minimum, optimum and maximum. The optimum is the temperature at which the bacteria will grow most rapidly, whilst temperatures below the minimum and above the maximum no growth will occur. (Prescott et al. 2008..) Growth rate decreases rapidly once temperatures exceed the optimal rate placing the maximum rate very close to it, whilst the minimum temperature is much further away from the optimum. (Ingraham et al..1990) The cardinal temperatures vary between each species of bacteria which places them into subcategories relevant to these experiments as shown below:-