https://padlet.com/373453/m2ikxykq4oe0qtfe en-us 2021-04-23 12:37:24 UTC 2025-11-09 00:49:45 UTC hello@padlet.com 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1501914115 Thomas Hunt Morgan started his journey experimenting with fruit flies. Through his observations he was able to establish that genes are physically located on chromosomes. His experiments on the fly's eyes were the proof that chromosomes had genes on them. His findings were also able to support the theory that genes were linked together.]]> 2021-05-07 12:12:51 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1501914115 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1501958608 Bacteriologist, Frederick Griffith was the first person to show bacterial transformation. In order to demonstrate this transformation he used two strands of streptococcus, type S and type R. The type S strain when injected into the mouse would cause it to die and the type R strain would not have an effect on the mouse. Then Griffith injected the mouse with a heat killed and smooth strain which allowed the mouse to live, but when the heat killed was mixed with the rough strain, the mouse died. With this he noticed a transformation that was discovered by other scientists.]]> 2021-05-07 12:28:00 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1501958608 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502002078 These men were able to explain Frederick Griffith's results with experiments of their own. They determined what caused the transformation by taking the live rough mouse and the heat strain, simmilar to Griffith, however they mixed them with one of 2 enzymes. One group mixed with protease(destroys protein) and the other mixed with DNase(destroys DNA). So, they injected the mouse with the two different enzymes and the mouse with the protease died while the one with the DNase lived. This showed the DNA was responsible for the transformation because when it was destroyed in the mouse, it was able to live. ]]> 2021-05-07 12:40:28 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502002078 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502038482 Observed different organisms and measured the amounts of the four bases. Through the observations he noticed a trend that adenine and thymine had a similar amount and cytosine and guanine had a similar amount. After testing multiple organisms and finding the same results he was able to come up with rules. The amount of adenine and thymine were always in balance and the amount of guanine and cytosine were always in balance. He did not know the importance of his findings at the time but he shared them with Watson and crick who were able to use his finding to advance scientific discovery. ]]> 2021-05-07 12:50:36 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502038482 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502318837 Hershey and Chase experimented with phages. They used a bacteria cell as the host in their experiment and took the bacteriophages and labels them one of two ways. One with radioactive sulfur that allowed them to follow the proteins in the sulfur or they used radioactive DNA to follow the movement of DNA during the infection. So they took the labeled phages and allowed them to infect the bacteria and then separate by centrifugation. The result from the sulfur label was there was no radioactive material inside the pellet, it was all supernatant. From their experiments they concluded it was the DNA, not the protein that was the genetic material. ]]> 2021-05-07 13:53:18 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502318837 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502425688 Rosalind Franklin was a x-ray crystallographer and she was the first person to have a wet image of what the double helix of DNA looks like. Her picture somehow got into the hands of Wilkins and he sent the image to Watson and crick who published the image and described it along with their findings. None of the three men mentioned the importance of her work in their discovery. ]]> 2021-05-07 14:15:00 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502425688 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502777658 Watson and Crick had a goal of discovering the structure of DNA. They started out with a double helix with sugars and phosphates at the center and the nucleases facing the outside. This model was far from being correct and could even be described as embarrassing for them. So later on a man named Maurice Wilkins stole a photo from Rosalind Franklin and gave it to Watson and Crick. They were able to analyze the photo and publish the finding. However it was not their photo to publish and they did not even credit Franklin in the paper. ]]> 2021-05-07 15:27:08 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502777658 373453 https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502943346 Meselsen and Stahl took the findings of the Watson and Crick experiment and expanded on it with a further question: how does it make a copy of itself? They made three proposals to try to find the answer to this question. 1. It could unfold in the middle and then it could copy new templates on either side. 2. The conservative theory that somehow DNA was wrapped around histone proteins and then it would make an exact duplicate of itself. 3. The dispersive model that maybe it would chunk itself into small nucleotide segments. Then they did experiments to find which proposal was correct. ]]> 2021-05-07 16:00:48 UTC https://padlet.com/373453/m2ikxykq4oe0qtfe/wish/1502943346