Question

In this lesson, you created a summary of some of the experiments and knowledge that led to the discovery of the DNA molecule. Attention Students: You may want to go through Module 7 before you start this assignment because it will give you further knowledge of the acceptance of DNA. (You'll notice that there is no other assignment for Module 7.)

Now your job is to create a timeline with the scientists and their discoveries that led to DNA being accepted as the molecule of inheritance. Your final product will be a timeline with a summary of the important information.

Use your imagination to create a format in which to display the information in a form that you can submit to your teacher. If in doubt, check with your teacher first to see if the format will be acceptable. It must be digital but you can start on paper and then scan your work into a digital format. Your submission must be informative and should accurately display the timeline that will run from about 1900 to the present time.

You must include at least two scientists that contributed to our knowledge of this molecule that IS NOT given in this template. If you kept your eyes open as you completed your research, you should have discovered quite a few important scientists that you could choose from. Include these individual or groups of scientists with a summary of their contributions on your timeline. You can go to Nobelprize.org for some very good information. This is a searchable website. Try to cover the timeline so that the contributions are spread out over time.

Marks

• Timeline – from 1900 to present = 2 marks
• Inclusion of the given scientists and their contributions = 3 x 3 = 9 marks
• Inclusion of two other contributors to DNA discovery = 2 x 3 = 6
• Sources of information provided for all information presented = 2 marks

Total = 19 marks

Answer 1

DNA is the genetic material now we know that but if we recall the experiment of origin of life then we got to know that the scientists only found RNA and protein, then they concluded that the may be the first genetic material is RNA. Mendel call the unit of inheritance "Factor".

• In 1869 a Swiss physiological chemist Friedrich Miescher first identified some kind of material not having the properties like protein and called it NUCLIEN inside the nuclie of human WBCs (leukocytes), then after NUCLIEN was named Nucliec Acid and now known as DNA (Deoxyribo nucliec acid).
• Friedrich Miescher was intended to isolate the protein content of the WBCs, so he managed to get the used, pus coated bandages of the patients from the local clinics.
• When he received those pus coated used bandages, he washed them and filter out the WBCs and finally extracted and identified various proteins of leukocytes, In between extracting and identifying the proteins of WBCs he found a substance from the nucleus of the cell which do have different chemical properties than protein. It was have very high content of phosphorus and resist to proteolysis. Then he realized that he discovered a new substance.

Miescher wrote that " it seems probable to me that a whole family of such slightly varying phosphorus containing substances will appear as a group of Nucliens, equivalent to proteins.    

• A Russian biochemist Phoebus Levene investigated the structure of DNA.
• In 1950 Watson and crick gave the Double helix Mode of DNA.
• Chargaff's Rule was A+T/G+C =1.
• In search of Genetic Material the first experiment was of Fredrich Griffith in 1928, known as Transforming principle.
• Then finally in 1952 Alfred Harshey and Martha Chase proved that DNA is the genetic material by the experiment done on E.Coli and Bacteriophage.