AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

STRUCTURE OF NUCLEIC ACIDS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Who was Chargaff?
A
This person came up with:A=T, G=C, This American biochemist discovered a quantity pattern in the DNA, came up with a rule named after him, Watson and Crick’s structure supports this person’s findings
B
Created the first 3D model of the DNA double-helix
C
Determined that DNA was our genetic code
Explanation: 

Detailed explanation-1: -Chargaff’s ratios, 3D animation with narration. Erwin Chargaff found that in DNA, the ratios of adenine (A) to thymine (T) and guanine (G) to cytosine (C) are equal. This parity is obvious in the final DNA structure.

Detailed explanation-2: -Chargaff’s realization that A = T and C = G, combined with some crucially important X-ray crystallography work by English researchers Rosalind Franklin and Maurice Wilkins, contributed to Watson and Crick’s derivation of the three-dimensional, double-helical model for the structure of DNA.

Detailed explanation-3: -Key conclusions from Erwin Chargaff’s work are now known as Chargaff’s rules. The first and best known achievement was to show that in natural DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units.

Detailed explanation-4: -Erwin Chargaff’s research paved the way for the discoveries of DNA’s structure and its method of replication. His observation that DNA varies from species to species made it highly credible that DNA was genetic material.

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