Read the article (see attachment)then answer the three questions: (For each question one paragraph) Question 1: In their paper "A structure for deoxyribose nucleic acid" (Nature. 1953), Watson and Crick wrote that: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material. Question 1: Explain this sentence. What do Watson and Crick meant by "specific pairing we have postulated? Also, what is the "possible copying mechanism for the genetic material" that their proposed structure suggests? Question 2: Erwin Chargaff (1905 2002) was a Professor of Biochemistry at Columbia University and through experimentation he discovered 2 rules which were fundamental for the development of the DNA model by Watson and Crick. The first Chargaff's rule states that in any specie observed (from bacteria to humans), the ratio of adenine to thymine and the ratio of guanine to cytosine are always equal to 1. In other words: [A] / [T] = [G] / [C] =1 Question 2: Explain Chargaff's first rule based on the DNA structure proposed by Watson and Crick. Question 3: The second Chargaff's rule states that in all species observed (from bacteria to humans. the relative proportion of the pairs adenine-thymine and guanine-cytosine varies. For example: In humans, A+T = 60% and C+G = 40% In E. coli, A+T = 48% and C+G = 52% Question 3: Explain Chargaff's second rule based on the DNA structure proposed by Watson and Crick. Remember: a. Students will be graded according with clarity of text and content. Points will be deduced for incomplete and/or incoherent sentences, plagiarism, as well as superficial explanations. b. I expect that you will search peer-reviewed articles (www.pubmed, gov) and bring material that will be relevant to your writing.

Read the article (see attachment)then answer the three questions: (For each question one paragraph) Question 1: In their paper "A structure for deoxyribose nucleic acid" (Nature. 1953), Watson and Crick wrote that: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material. Question 1: Explain this sentence. What do Watson and Crick meant by "specific pairing we have postulated? Also, what is the "possible copying mechanism for the genetic material" that their proposed structure suggests? Question 2: Erwin Chargaff (1905 2002) was a Professor of Biochemistry at Columbia University and through experimentation he discovered 2 rules which were fundamental for the development of the DNA model by Watson and Crick. The first Chargaff's rule states that in any specie observed (from bacteria to humans), the ratio of adenine to thymine and the ratio of guanine to cytosine are always equal to 1. In other words: [A] / [T] = [G] / [C] =1 Question 2: Explain Chargaff's first rule based on the DNA structure proposed by Watson and Crick. Question 3: The second Chargaff's rule states that in all species observed (from bacteria to humans. the relative proportion of the pairs adenine-thymine and guanine-cytosine varies. For example: In humans, A+T = 60% and C+G = 40% In E. coli, A+T = 48% and C+G = 52% Question 3: Explain Chargaff's second rule based on the DNA structure proposed by Watson and Crick. Remember: a. Students will be graded according with clarity of text and content. Points will be deduced for incomplete and/or incoherent sentences, plagiarism, as well as superficial explanations. b. I expect that you will search peer-reviewed articles (www.pubmed, gov) and bring material that will be relevant to your writing.