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6 -- Part 5: Microbial Growth
The loop lated colonies.
The colonies can be picked up with an inocu.
In the second and third series, the loop picks the lating loop and transfers it to a test tube to culture a single type of bacterium.
There are many variations of this pattern.
When the organ types are red and yellow, the streak plate method works well.
Humans on the Space Station would die instantly from cold and the vacuum of space if it were to suddenly burst.
Direct and indirect methods of measuring cell temperature can be used.
It's important to be able to determine tures from 250 to 295degC.
The culture can usu numbers directly by counting or indirectly by ally, which can be thawed and cultured several years later.
They measured their metabolism activity.
While under vacuum, the container is sealed by melting the rial growth, not a glass with a high-temperature torch.
The size of the individual cells increases.
The organisms can be revived by hydration with a liquid medium.
The cells are replicated.
When the number of cells in each genera tion is expressed as a power of 2, the exponent tells the number of doublings that have occurred.
It varies depending on the environment and the organisms.
A generation time of 1 to 3 hours is the average for mostbacteria.
An enormous number of cells will be produced.
25 is the number of generations indicated by the superscript.
To arrive at the numbers in the center column, certain actinomycetes reproduce by using the yx key on your calculator.
The number 32 will be shown on the calculator.
A few colonies ofbacteria will have 32 cells.
The log key on your calculator can be used to arrive at the numbers in the right-hand column.
Simply fragment, and the fragments initiate the growth of the number 32, then press the log key.
The rounded cells will be shown by the calculator.
It's hard to graph population changes using numbers.
The graph logarithmic plot point for the tenth generation (3.01) has been drawn so that the curves intersect up the graph.
The figure shows how graphs of changes in the number ofbacteria would increase the plots rather than decreasing them.
Take the line off the page if it's at ten height of the graph.
If the numbers were plotted for two more generations.
We are not used to it and the cells are not active.
It is necessary for a period of intense metabolic activity involving, in proper understanding of graphs of microbial populations, that the population is thinking in logarithmic relationships.
The lag, log, which the population doubles, is one of the four basic phases of growth.
For a while, the number of cells changes very little because of the ferred for industrial purposes where, for example, a product cells do not immediately reproduce in a new medium.
Knowledge of the growth curve is important to understand population dynamics and population control in the course of infectious diseases, as well as in food preservation and spoilage.
Microbial death will be discussed in Chapter 7 if exponential growth continues.
The population curve would be the same as that of an 80,000-ton aircraft carrier if two mice started a family with a fixed food supply.
It's not always clear what causes exponential growth to stop.
The amount of waste products is proportional to cell numbers.
Population numbers are related to changes in the pH.
In the pop example, a millionth of a liter of sour milk is diminished to a tiny fraction of the number of cells.
There must be 70 times in the previous phase until the population dies out.
In serial dilutions, the original inoculum is changed in a series of tubes.
Each dilution tube will only have a fraction of the number of cells as the preceding one.
colonies can be counted using samples of the dilution used to inoculate the Petri plates.
The count is used to estimate the number ofbacteria in the sample.
It's not practical to measure out a millionth of a millionth of a gram of food in some applications.
It's not possible to hold a particular lot for this length of time.
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