Answer:
In 1928, Fred Griffith performed an experiment revealing that genetic material can be passed between two different stains of the bacteria.
Explanation:
In 1928, Frederick Griffith, a British bacteriologist conducted some experiments to develop a pneumonia vaccine. He used mice and two strains of Streptococcus pneumoniae bacteria, known as R and S in his experiments.
The live R strain bacteria had a rough appearance and were nonvirulent. When he injected R bacteria into mice, they did not cause pneumonia. The live S strain bacteria had a smooth appearance due to their polysaccharide coating and were virulent. When injected into mice, the mice died as a result of pneumonia. The polysaccharide coating protected the S bacteria from the immune system of the mice.
Griffith then injected mice with heat-killed S bacteria (the heat killed the bacterial cells) and they did not cause pneumonia in mice. But when he injected a combination of non-lethal R bacteria and non-lethal heat-killed S bacteria into mice, the mice died from pneumonia. When he examined the blood sample from the dead mice, he found that the blood sample contained live S bacteria. This finding leads him to the conclusion that the nonvirulent R-strain bacteria had been "transformed" into virulent and lethal S-strain bacteria by taking up a "transforming principle" from the heat-killed S bacteria.
This experiment was then used for additional experiments conducted by Avery, McCarty, McLeod and then by Hershey and Chase. They found the evidence that the transforming principle from Griffith's experiment was actually the hereditary material, DNA. The DNA of the S strain bacteria had survived the heating process. This DNA that contains the genes for the production of the protective polysaccharide coating was taken up by the R strain bacteria. The transformed R strain bacteria were now protected from their host's immune system and this process of transferring genetic information between different bacterial strains is known as transformation.
Answer:
There are many many things in the world that produces Carbon. The largest source of greenhouse gas emissions from human activities in the United States is from burning fossil fuels for electricity, heat, and transportation. All of these produce Carbon into the atmosphere and warm the planet
Answer: True
A point source pollution is a single identifiable source of pollution of air, water ,noise and soil. The pollutants being responsible for pollution can be easily traced back to their origin. The pipe, drain, well, container and ditch can allow the tracing back of the source of pollution coming from the sewage drain, household waste, industrial waste and agricultural waste.
Therefore, Point-source pollution comes from a specific location and is easy to trace is true.
Yeast means <span>microscopic fungus consisting of single oval cells that reproduce by budding, and are capable of converting sugar into alcohol and carbon dioxide.
mold is where we get medicine from.
mildew is </span>a thin whitish coating consisting of minute fungal hyphae, growing on plants or damp organic material such as paper or leather.
mushrooms increase spread and develop rapidly.
i hope this helps u.
