Bacterial growth is the asexual reproduction, or cell division, of a bacterium into two daughter cells, in a process called binary fission. Providing no mutational event occurs the resulting daughter cells are genetically identical to the original cell. Hence, "local doubling" of the bacterial population occurs. Both daughter cells from the division do not necessarily survive. However, if the number surviving exceeds unity on average, the bacterial population undergoes exponential growth.
Factors Required for Bacterial Growth
The requirements for bacterial growth are:
(A)) Environmental factors affecting growth, and
(B) Sources of metabolic energy.
A. Environmental Factors affecting Growth
1. Nutrients. Nutrients in growth media must contain
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Exponential Phase or Logarithmic (Log) Phase. The cells multiply at the maximum rate in this exponential phase, i.e. there is linear relationship between time and logarithm of the number of cells. Mass increases in an exponential manner. This continues until one of two things happens: either one or more nutrients in the medium become exhausted, or toxic metabolic products, accumulate and inhibit growth. Nutrient oxygen becomes limited for aerobic organisms. In exponential phase, the biomass increases exponentially with respect to time, i.e. the biomass doubles with each doubling time. The average time required for the population, or the biomass, to double is known as the generation time or doubling time. Linear plots of exponential growth can be produced by plotting the logarithm of biomass concentration as a function of time. Importance : Antibiotics act better at this phase.
3. Maximal Stationary Phase. Due to exhaustion of nutrients or accumulation of toxic products death of bacteria starts and the growth cease completely. The count remains stationary due to balance between multiplication and death rate. Importance: Production of exotoxins, antibiotics, metachromatic granules, and spore formation takes place in this phase.
4. Decline phase or death phase. In this phase there is progressive death of cells. However, some living bacteria use the breakdown products of dead bacteria as nutrient and remain as
Bacteria are living things that have only one cell. Under a microscope, they look like balls, rods, or spirals. Many are helpful. Some bacteria help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt.
Describe or diagram the lifecycle of a kelp. Life cycle of kelp can differ between perennial kelp and annual kelp. Yet both types of kelp live a two-stage life cycle. Their haploid phase begins when mature organisms release spores and then germinate to become male or female gametophytes. Their sexual reproduction then results in the diploid sporophyte stage, in which the male sperm and the female egg have fertilized.
On pages 5-6, the diffusion coefficient of growth factor in water D is quoted from literature, whilst for growth factor concentration C*, duration of cells differentiation phase T, and the cell death rate Γwn were merely taken from personal communication with an independent laboratory. The rate of cell proliferation Γnw, cell differentiation Γud, solute uptake ΓR1 and Michaelis-Menten uptake K were selected to fit experimental observations received in the same manner. These data are proven [1, 2] to deviate between cell types and in response to culture environmental variations. Authors are advised to either publish detailed experimental data in the appendices, or consult reviewed articles, then assess the sensitivity of the model to different species and perfusion
The Task: We started learning about exponents at the beginning of the nuclear culture unit. We learned about positive, negative, fractional, and zero exponents and their effects on the graph. Exponents make a graph exponential, meaning that the graph will either drastically increase rapidly or drastically decrease rapidly. We used our knowledge of exponential growth and decay to understand topics such as interest, population growth and decay, disease growth or decay, radioactive decay, and bacterial growth or decay; after this unit we were able to understand these topics and graph them. The most beneficial concept in this unit was understanding how interest grows and decays.
G1 is the main development period of the cell cycle. In G1, the cell plans to experience cell division. The cell still plays out the majority of its typical capacities, however begins to get greater. The cell then starts to make a duplicate of the cell parts (organelles). It additionally starts to create RNA and orchestrate proteins to prepare to separate.
Introduction A mutation is a heritable change that is passed from the mother cell to progeny cells. Mutations may lead to good, bad or neutral phenotypic changes in the organism. They may occur spontaneously as in random DNA replicative errors or may be induced by mutagenic chemicals or radiation. Besides mutations, another way that bacteria achieve gene diversity is through the three known mechanisms for intercellular gene transfer.
In this lab, the goal was to transform bacteria with genes that included fluorescence as well as antibiotic resistance that were taken from a jellyfish. Transformation is transferring a gene from one organism to another. Certain precautions had to be made before doing this lab since every step had to be done very quickly to prevent too much contamination. The first step in starting the transformation is to add the transformation solution into the +pGLO and -pGLO test tubes. After this is done, you put both tubes in ice and then put bacteria in both tubes.
The purpose of this lab was to perform a procedure known as genetic transformation which allowed us to genetically engineer E. Coli to be ampicillin resistance. Before the lab we expected that lysogeny broth and minus DNA will have growth but no glow. The lysogeny broth, ampicillin, and
Being able to identify unknown microbes from systematic testing is what makes the field of microbiology so important, especially in infectious disease control. Using the testing procedure laid out by the microbiology field we are able to identify unknown bacteria present in our everyday lives, and along the way learn a lot about their characteristics that separate them from other types of bacteria. Being able to do this is vital in order for us to understand why microbes are present in certain places, how they are able to grow and what restricts their growth, that way they can be combatted if necessary. These techniques for determining unknowns are also important for isolating and testing infectious disease microbes in order to prevent spreading. Another important aspect of being able to identify unknown microbes is the
Based on the observations collected over the three species, interphase is by far the longest phase, and metaphase, anaphase, and telophase are similar in length, with telophase being slightly shorter. In the broad bean, almost all of the cells were in interphase, for reasons stated in the previous question. In the onion root, about 3/4 of the cells were in interphase, with most of the rest in prophase, and a few in metaphase, anaphase, and telophase. The whitefish had about 70% in interphase, with most of the rest in prophase (15%) , and more in metaphase than in the previous species (6%). The whitefish could have had more cells in metaphase because being animal cells, they require the centrosomes to align at opposite poles, which may cause it to take longer.
The purpose of this experiment was to insert the plasmid glow green into the bacteria with a gene of interest to produce the protein that make the bacteria glow green along with the presence of arabinose and the presence of ampicillin. Many scientists are experimenting different kind of genes that can inserted into the organism for survival. The technique of transformation was used in this experiment to give the organism a new trait that they did not possess in their life. In this experiment, the bacteria were added to four plates with certain conditions such as the existence of plasmid, ampicillin, and arabinose to see whether the bacteria grow and glow green. The results showed that the LB/amp/araC +pGLO produce a lot of colony and most
An endospore is a dormant of a bacterial cell. It is a non-reproductive structure that ensures survival of a bacterium through stressful environmental conditions. Unknown #76, using aseptic technique, was inoculated to a nutrient sporulation medium (NSM) plate. This concerns a selective medium that increases the initiation of endospore production. A spore-former would have green-pigmented endospore cells when looked at under the microscope.
The media used in this experiment was Trypticase nitrate broth. The reagents used (A and B) were sulfanilic acid and alpha-naphthylamine (respectively). Using aseptic technique, the bacterium (16A and 16B) were inoculated into labeled broth test tubes. The tubes were incubated for 48 hours at 37 degrees Celsius. When the incubation was complete 5 drops of reagent A and 5 drops of reagent B were added to each of the broths.