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Bacteria are single celled, prokaryotic organisms that live in colonies and can be found in almost any environment on the Earth. Bacteria lack a membrane-bound nucleus as well as other internal organelles that classify other cells as eukaryotic. A bacterium contains free-floating DNA in a thread-like mass called a nucleoid. Bacteria also contain ribosomes to assemble proteins into individual amino acids using encoded information on a messenger RNA strand. The external structure of bacteria typically consist of an outer cell wall and an inner cell membrane, designed as protective layers for the bacterium.(Robert & Kadner, 2015, February 22)
There are several different types of bacteria which are generally separated by their structure. These classes of bacteria are known as cocci, bacilli, and other various forms. Cocci are spherical-shaped bacteria that is then further divided into subcategories based on the number and arrangements of the bacterium. A cocci bacteria is a single sphere-shaped bacterium. Diplococcus is an arrangement of two cocci bacteria conjoined. Staphylococcus is an arrangement of cocci bacteria in a cluster, similar to that of a grape-like structure. Streptococcus is an arrangement of cocci bacteria in a strand-like formation. Sarcina bacteria are clusters of eight cocci bacteria arranged in a cube-like structure. Tetrad bacteria are arranged in a group of four conjoined cocci bacteria. Bacilli bacteria are then divided into bacillus, which are a single rod-shaped bacteria. Diplobacillus are two conjoined bacilli bacteria. Streptobacillus are an arrangement of bacilli bacteria in a strand formation. Coccobacillus is a single circular-shaped and rod-shaped bacteria, similar to that of cocci bacteria, yet rod-shaped as well. Bacteria are then further classified by their appearance to the naked eye. Once a colony has grown to a size where it is visible to the naked eye, a color and relative shape of the colony is visible. Bacteria are then classified based on their colony shape and color. These colonies can exhibit colors such as white, cream, yellow, orange, or red and can be either a round shaped colony or an irregular shaped colony.( Pan & Hu, 2015)
Bacteria reproduce very quickly, going through a process called binary fission, which can turn a colony of only a few thousand to a colony of several hundred thousand within the span of a few hours. This process begins with a single bacterial cell that then divides into two, producing genetically identical daughter cells. This occurs as the nucleus of the parent cell replicates and splits into two identical sets of bacterial DNA. The two daughter cells then have the ability to split like the parent cell, thus resulting in four, genetically identical bacteria. This process will continue for hours and can result in large colonies developing in a very short amount of time. In favorable the number of reproduced bacterial cells is even higher. In these conditions some bacteria can even divide every twenty minutes resulting in fast growing colonies. This process can produce over then produce millions of bacterial cells within mere hours.(Postlethwait and Hopson, 2009 )
Bacteria can survive in almost every environment on Earth, ranging from under-sea vents to below the surface of the Earth. Other bacteria can even be found within the digestive tracts of animals. The bacteria that survive these environments must be extremophiles, bacteria that are resilient to extreme temperatures. Psychrophiles are bacteria that thrive in temperatures ranging from -15 to 10 degrees celsius and are often bacteria found beneath the Earth. Psychrotrophs can survive in temperatures of 0 degrees celsius, but prefer temperatures of mesophiles. Mesophiles are bacteria that thrive in temperatures between 20 and 45 degrees celsius. Thermophiles thrive in temperatures ranging from 45 to 122 degrees celsius. Hyperthermophiles are bacteria that thrive in temperatures from 80 degrees celsius or higher and are the most resilient to extreme heat.(Anonymous, 2018)
The purpose of this experiment is to test and observe the effect temperature has on various bacteria samples.
The data recorded during the duration of this experiment validate the claim that bacterial growth is slowed in harsher environments. This is evident by the curve of the reproductive rate observed in Graph 3. This curve could be caused because of the bacteria’s affinity toward mesophilic temperatures, moderate temperatures. This affinity also explains why the bacteria were still able to reproduce in the harsher environment, even though their reproductive rates had been affected by the detrimental environment that the bacteria were placed within. Thus the sharp decline in reproduction can be attributed to the harsher environment the bacteria experienced, as is evident by Graph 3. Following this logic it is reasonable to conclude that in ideal conditions these bacteria can reproduce a high rates, however once placed in harsher environments their reproductive capabilities are lessened as seen in Graph 3.

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