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Why were the S bacteria not the R bacteria virulent?
The S bacteria are surrounded by a capsule, so it is not engulfed by the host's white blood cells. That means that it is able to proliferate and spread. The R bacteria lack the capsule (like the mutant S bacteria), so the white blood cells are able to detect and eliminate them.
Why did the mice die when giffith mixed the live R bacteria and the heat killed S bacteria?
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Who is the Scientist discovered nonvirulent bacteria transformed into virulent bacteria?
Frederick Griffith discovered the phenomenon wherein exogenous DNA of heat killed virulent bacteria was taken up by a similar but non-virulent bacteria. This resulted in the transformation of the living bacterial cells into the virulent variety. This was prior to the understanding that DNA was the genetic material and the hereditary information passed onto the living bacteria was referred to as the "transforming principle." Source : Russell "iGenetics : A Molecular Approach."
How would you use the word virulent in a sentence?
Virulent means actively poisonous. You could use it in a sentence as, "the man had a virulent snake bite."
Who Was responsible for the experiment with mice and bacteria that led to the hypothesis that when two bacteria were mixed together something was passed to the living cells?
This experiment was conducted by Frederick Griffith in 1928. He observed that when he mixed a harmless strain of bacteria with a heat-killed virulent strain, the harmless bacteria were transformed into a virulent form. This led to the hypothesis that something in the heat-killed bacteria had transformed the live bacteria.
Why was the mixture of S bacteria and R BACTERIA virulent?
The live R bacteria acquired a capsule and became live, virulent S bacteria.
Why was the mixture of heat killed s bacteria and r bacteria virulent?
The live R bacteria acquired a capsule and became live, virulent S bacteria.
What did Griffith find to be true after his experiments with the s and r strain of bacteria?
Griffith hypothesized that a chemical component from the virulent S cells had somehow transformed the R cells into the more virulent S form.
What did fred griffith find to be true after his experiment with the S and R strains of bacteria?
Fred Griffith found that genetic information could be transferred between different strains of bacteria, specifically between the harmless R strain and the virulent S strain of bacteria. This led to the discovery of transformation, a process where genetic material is exchanged between bacteria.
Why were the S bacteria not the R bacteria virulent?
The S bacteria are surrounded by a capsule, so it is not engulfed by the host's white blood cells. That means that it is able to proliferate and spread. The R bacteria lack the capsule (like the mutant S bacteria), so the white blood cells are able to detect and eliminate them.
What was the molecule that caused transformation in Griffith's pneumonia experiment?
The molecule that caused transformation in Griffith's pneumonia experiment was DNA. Specifically, it was the transfer of DNA from heat-killed virulent bacteria to live non-virulent bacteria that resulted in the transformation of the non-virulent bacteria into a virulent form.
What were Griffith's transformation experiments are?
Griffith's transformation experiments, conducted in 1928, involved studying two strains of Streptococcus pneumoniae in mice: a virulent smooth strain (S) and a non-virulent rough strain (R). He discovered that when he injected mice with heat-killed S strain bacteria mixed with live R strain bacteria, the mice developed pneumonia and died. This indicated that some "transforming principle" from the dead S strain had converted the live R strain into a virulent form. Griffith's work laid the groundwork for later discoveries about DNA as the genetic material.
What does virulent bacteria mean?
Virulent bacteria are ones that are able to cause disease. Examples of potentially virulent bacteria are Staphylococcus aureus and Neisseria gonorrhea.
How would use virulent be used in a sentence?
this bacteria is virulent strain
Which scientist are cretided with the discovery that DNA is the chemical capable of transforming live R cells in mice?
The discovery that DNA is the chemical responsible for transforming live R cells in mice is credited to Frederick Griffith. In his 1928 experiments with Streptococcus pneumoniae, Griffith demonstrated that non-virulent R strain bacteria could be transformed into virulent S strain bacteria when exposed to heat-killed S strain. This transformative principle was later identified as DNA by Avery, MacLeod, and McCarty in 1944.
What is the S strain of bacteria about the cause disease in animals but a R strain is not?
The S strain of bacteria is virulent due to its ability to produce a protective capsule that helps it evade the host's immune system, allowing it to cause disease in animals. In contrast, the R strain lacks this capsule and is non-virulent, meaning it cannot effectively evade the immune response and does not cause disease. This difference in pathogenicity is a key factor in understanding bacterial infections and their effects on host organisms.
How did Griffith experiments show that hereditary factor was involved in the bacterial transformation?
Griffith's experiments, conducted in the 1920s, demonstrated that non-virulent strains of Streptococcus pneumoniae could be transformed into virulent strains when exposed to heat-killed virulent bacteria. He observed that when live non-virulent bacteria were mixed with the heat-killed virulent bacteria, some of the non-virulent bacteria took up the hereditary material from the dead bacteria, becoming virulent themselves. This transformation indicated the presence of a "hereditary factor" that carried the information necessary for virulence, laying the groundwork for the later discovery of DNA as the genetic material.
