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svet-max [94.6K]
3 years ago
14

An early method of evaluating the effectiveness of an antimicrobial chemical is to compare it's effectiveness to that of

Biology
1 answer:
Nimfa-mama [501]3 years ago
7 0

Answer:

The effectiveness of chemical disinfectants has historically been compared to phenol.

Explanation:

The effectiveness of a disinfectant or antiseptic can be determined in a number of ways. Historically, a chemical agent’s effectiveness was often compared with that of phenol, the first chemical agent used by Joseph Lister. In 1903, British chemists Samuel Rideal (1863–1929) and J. T. Ainslie Walker (1868–1930) established a protocol to compare the effectiveness of a variety of chemicals with that of phenol, using as their test organisms Staphylococcus aureus (a gram-positive bacterium) and Salmonella enterica serovar Typhi (a gram-negative bacterium). They exposed the test bacteria to the antimicrobial chemical solutions diluted in water for 7.5 minutes. They then calculated a phenol coefficient for each chemical for each of the two bacteria tested. A phenol coefficient of 1.0 means that the chemical agent has about the same level of effectiveness as phenol. A chemical agent with a phenol coefficient of less than 1.0 is less effective than phenol. An example is formalin, with phenol coefficients of 0.3 (S. aureus) and 0.7 (S. enterica serovar Typhi). A chemical agent with a phenol coefficient greater than 1.0 is more effective than phenol, such as chloramine, with phenol coefficients of 133 and 100, respectively. Although the phenol coefficient was once a useful measure of effectiveness, it is no longer commonly used because the conditions and organisms used were arbitrarily chosen.

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Answer:

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Explanation:

The options are:

A. Bacterial and eukaryotic cells are more closely related to  each other than to archaeans, as evidenced by the fact that  bacteria and eukaryotes do not inhabit the most extreme  environments.

B. Although their cell structures are very different, archaean and  eukaryotic cells are more closely related to each other than to  bacteria, as evidenced by the fact that Bacteria was the first  domain to split from the shared ancestor of Archaea and  Eukarya.

C. Bacteria and archaeans are more closely related to each other  than to eukaryotes, as evidenced by their cell structures. Bacteria  and archaeans are prokaryotic, while all eukaryotic cells contain  mitochondria and other membrane-bound organelles.

D. The three domains of life are equally divergent from one  another, so no two domains are more closely related to each other.  This is supported by the evolutionary tree of life because three  branches extend from one node millions of years ago.

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Archaea and bacteria are similar in terms of cellular organisation and size but are however similar to eukaryotes (eukarya) at the molecular level. Archaea and Eukaryotes both undergo DNA replication and protein synthesis the same mechanism. Both of them posses closely related genes and several metabolic pathways, including the enzymes in transcription and translation.

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