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What are 4 steps in Griffith's experiments?
S Strain ---> inject into mice ---> Mice Die R Strain ---> inject into mice ---> Mice Live Griffith was able to kill bacteria by heating them. He observed that heat-killed S Strain bacteria injected into mice did not kill them. When he S Strain (heat Killed) ---> Injected into mice ---> Mice Live S Strain ( heat Killed) + R Strain (Live) ---> Injected into mice ---> Mice Die
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 did Fred Griffith discover when he injected mice with a mixture of dead pathogenic S cells and living harmless r cells of Streptococcus pneumonia?
Fred Griffith discovered that the harmless R strain of Streptococcus pneumoniae could be transformed into the deadly S strain when mixed with heat-killed S strain bacteria. This experiment provided evidence for the concept of bacterial transformation, where genetic material can be transferred between different strains of bacteria.
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 happens when heat-killed S-strain pneumococcus were injected into a mouse along with live R-strain pneumococcus?
A very important characteristic about bacteria actually created live S-strain to exist in the dead injected mouse. Bacteria is competent, in biological terms, meaning that cells can take up "naked" DNA from it's environment. Knowing that fact, when the heat-killed S-strain pneumoccus mixed with the live R-strain, the R-strain took in the DNA, therefore inheriting the deadly coating of the S-strain. So the R became S, and killed the mouse.
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.
How many phonemes in the word strain?
There are 6 phonemes in the word "strain": /s/ /t/ /r/ /ā/ /n/ /n/.
What was the variable in Oswald Avery's experiment?
The variable in Oswald Avery's experiment was the type of enzyme used to break down the polysaccharide capsule in the heat-killed S strain bacteria. By using different enzymes, Avery was able to determine which specific molecule was responsible for transforming the R strain bacteria into the pathogenic S strain.
How many phonemes innthe word strain?
The word "strain" has five phonemes: /s/ /t/ /r/ /ei/ /n/.
What was the significance of Frederick Griffith's experiments with Streptococcus pneumoniae?
Frederick Griffith's experiments demonstrated the phenomenon of bacterial transformation, showing that genetic material can be transferred between bacteria. This discovery laid the foundation for understanding DNA as the genetic material and the mechanism of bacterial virulence. It also played a key role in the development of molecular biology.
Why is an s strain of bacteria able to cause disease in mammals but a r strain is not?
An S strain of bacteria has a capsule that protects it from the host's immune system, allowing it to cause disease. In contrast, an R strain lacks this protective capsule, making it more vulnerable to the immune system and less able to cause disease.
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.
