Tough Biology Question. See If You Can Answer It???

Question

Discuss experiments that lead scientists to understand that DNA is the genetic material. Include the experiments of Hershey and Chase which used viruses of bacteria to demonstrate that DNA, not proteins carry genetic information.

Answer 1

not that tough. look it up.

Answer 2

Well before we get to the Hershey and Chase experiment, several important observations and experiments were done to really implicate DNA as the genetic material. Griffith in 1928 observed that heat killed bacteria (S-type) could transform a different type of bacteria (R-type) into the S-type category. In this case R-type produced rough looking colonies and S-type smooth colonies when grown on a petri dish. He showed that while the R-type when injected into mice is harmless, the S-type will kill the mouse but when heat killed S-type is also harmless. This in itself is not very interesting, but what was absolutly amazing is that when you co-inject heat killed S-type with live R-type bacterium the mice do not survive, thus something from the heat killed S-type bacterium "transformed" the R-type. Later Avery showed that only by the enzymes that degrade a specific type of nucleic acids could prevent this transforming activity, and that proteins and carbohydrates and lipids were not the cause of the activity. At this point, in 1944, it was all but formally demonstrated that this specific type of nucleic acid, DNA, was the transforming or genetic material. In 1952 Hershey and Chase come onto the scene with a very elegant experiment. Taking advantage of the fact that nucleic acids contains phosphorous while proteins do not, and proteins but not nucleic acids contain sulfur, Hershey and Chase decided to differentially label the nucleic acids and proteins of a bacteriophage to determine what is the material that gets injected into the bacterium. The hope was this would determine the material responsible for the generation of new bacteriophages, the genetic material. Nucleic acids were labeled with 32-P and the proteins labeled with 35-S. In the first experiment, the 32-P labeled phages were incubated with unlabeled bacterium. What Hershey and Chase observed was that 32-P entered the bacteria cells and that the generation of phages that burst out from the bacterium contained 32-P as well. When 35-S labeled phages were incubated with unlabeled bacterium, no 35-S was detected inside the cells or in the next generation of phages that were produced from the infected cells, it was only found outside of the cells. What this demonstrated was that the protein coat of the bacteriophages stayed outside the cell it infected while the nucleic acids penetrated the cell. Since they new the nucleic acid content inside the bacteriphage capsid was DNA, and that previously it had been shown that DNA is required for production of new phages during the infectious process Hershey and Chase concluded that DNA and not protein must be the genetic material.

Answer 3

somewhat sleepy to reply to the entire question... look up Watson & Crick (& Rosalind Frankin)... They received the Nobel Prize for putting each little thing mutually. some those who shaped a "base" for them to charm to upon contain Avery and Chargaff. In connection with Hershey and Chase, they contaminated 2 communities of micro organism with a corresponding bacteriophages (=viruses certain to micro organism). One phage's protein pill change into radioactively labelled with sulfur, the different phage's DNA change into labelled with radioactive phosphorus. After an infection/culturing each crew, they "shook away" any phages nevertheless connected to the cells and pelleted the contaminated cells, keeping apart them from the supernatant. Radioactive phosphorus change into regularly got here across *interior* the contaminated cells (the in uncomplicated words position it would want to be sensible genetically), even as radioactive sulfur change into regularly got here across floating round interior the supernatant (no longer doing a lot of something).

Answer 4

Basically they use phosphorus to label DNA and Sulfur to label Protein. What they did was expose the bacterium to only DNA, and in another experiment they expose the bacterium to Protein And what they found is only Phosphorus is inside bacterium.

Answer 5

We could reach till DNA now, This is a power of Allah, And actual Knowledge of Allah and we are searching only the Ability.

DNA can test by simple swap.

Answer 6

Why should we be the ones to do your school assignment for you?

Do your own work.

I'm telling your teacher.

Answer 7

I agree that's a really easy question.

Answer 8

That's not a hard question. Do your own homework.

Answer 9

LOL. Don't you have a book?