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Why was the mixture of heat-killed S bacteria and R bacteria and R bacteria virulent?
Wiki User
∙ 12y ago
It depends on how much heat is added. Most pathogenic bacteria are mesophiles, meaning that they thrive in medium temperatures. The optimal temperature is about 37 °C (99 °F), which is understandable considering that is our normal body temperature.
Pathogenes in food are required to be killed off with 72 °C for 16 seconds, 70 °C for 2 minutes or 63 °C for 30 min. Regulations depend on country.
This does not kill all pathogens, but enough to make it risk free to consume; one wants to reduce the adverse effect on taste at the same time.
For conserves a higher temperature is prescribed: 121 °C.
Freezing and dry heat are not safe ways to kill bacteria, as they can survive in an extremely resistant spore state (endospores).
At 150 °C the DNA starts to be destroyed, however.
If you heat bacteria using flame, such as with an inoculating loop over a Bunsen burner, they will be incinerated and die. Most bacteria are washed off, not killed, when you wash your hands. Usually shower and bath water is not hot enough to kill bacteria either. Alcohol is antiseptic, however. Some thermophilic bacterialike organisms can tolerate volcanic temperatures (to 130 °C), but these are archaea that will not harm anyone.
Wiki User
∙ 9y ago
The mixture contained heat-killed S bacteria, which released their genetic material, including the virulence factor, enabling the R bacteria to incorporate it through genetic recombination. This transformed the R bacteria into a virulent strain capable of causing disease.
Wiki User
∙ 13y agoThe heat killed enzymes in the bacteria that allowed the bacteria to reproduce. Because of the very short bacterial lives, this disallowed the bacteria from having a chance to infect the mice. However, when mixed with the R bacteria, the S bacteria transferred genetic information even though they were unable to reproduce.
Wiki User
∙ 12y agoAdd your answer:
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Why was the mixture of S bacteria and R BACTERIA virulent?
The live R bacteria acquired a capsule and became live, virulent S bacteria.
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.
What are two ways that rough bacteria differ from smooth bacteria?
Streptococcus pneumoniae bacteria is found in two types: a type III-S (smooth) and type II-R (rough) strain. The smooth strain covers itself with a polysaccharide capsule that protects it from the host's immune system, resulting in the death of the host, while the II-R strain doesn't have that protective capsule and is defeated by the host's immune system.The smooth type has a "coat" that prevents it from attacks from the host's immune system and it is very virulent.
What is part of a bacteria cell?
A bacteria cell is where all of you r bacteria gather up
What was the purpose of Frederick Griffith's studies?
Frederick Griffith's studies aimed to investigate the transformation of nonvirulent bacteria into virulent bacteria. He conducted experiments with Streptococcus pneumoniae to understand how genetic information could be transferred between different bacterial strains. This work laid the foundation for the discovery of DNA as the genetic material.
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.
Why were the S bacteria but not the R bacteria virulent?
The S bacteria possess a protective polysaccharide capsule that helps them evade the immune system, allowing them to survive and cause infection. The R bacteria lack this capsule and are easily targeted and eliminated by the immune system, thus they are not virulent.
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.
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.
Why were the S bacteria not the R bacteria virulent?
The S bacteria were not virulent because they lacked the capsule that is present in the R bacteria. The capsule is a protective layer that helps the bacteria evade the immune system of the host. Without the capsule, the S bacteria were unable to cause infection.
Why did the mice die when giffith mixed the live R bacteria and the heat killed S bacteria?
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What are two ways that rough bacteria differ from smooth bacteria?
Streptococcus pneumoniae bacteria is found in two types: a type III-S (smooth) and type II-R (rough) strain. The smooth strain covers itself with a polysaccharide capsule that protects it from the host's immune system, resulting in the death of the host, while the II-R strain doesn't have that protective capsule and is defeated by the host's immune system.The smooth type has a "coat" that prevents it from attacks from the host's immune system and it is very virulent.
What is part of a bacteria cell?
A bacteria cell is where all of you r bacteria gather up
What was the purpose of Frederick Griffith's studies?
Frederick Griffith's studies aimed to investigate the transformation of nonvirulent bacteria into virulent bacteria. He conducted experiments with Streptococcus pneumoniae to understand how genetic information could be transferred between different bacterial strains. This work laid the foundation for the discovery of DNA as the genetic material.
What was the different about the S bacteria and R bacteria?
the conversion of R forms of one type into S forms of a different type
What was different about the s bacteria and the r bacteria?
the conversion of R forms of one type into S forms of a different type
