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:
Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments.
Explanation:
Answer:
Revolving Service Structure (RSS) of launch pad 39B
<span>Compare: both RNA and DNA have 3 nitrogenous bases: Adenine Cytosine and Guanine. Also b</span>oth have a phosphate groups in their nucleotides<span>
Contrast: </span>RNA is a polymer with a ribose AND a phosphate backbone. It has four different nitrogenous bases: adenine, guanine, cytosine, and uracil.
DNA<span> is a long polymer with deoxyriboses AND phosphate backbone. It also has four </span>different<span> nitrogenous bases: adenine, guanine, cytosine and thymine.
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Hope this helps
Explanation:
A prominent difference between active and passive immunity is that active immunity is developed due to the production of antibodies in one's own body, while passive immunity is developed by antibodies that are produced outside and then introduced into the body.
