Daniel_8

Most Challenging words 1.chargaff 2.nitrogenous 3.purines 4.deciphering 5.photomicrographs 6.helix 7.Guanine 8.Pyrimidines 9.Cytosine 10.sugar-phosphate

Passage: The Structure of DNA Erwin Chargaff analyzed/the nitrogenous bases in many different forms of life/, concluding that the amount of **purines** /does not always equal the amount of pyrimidines /(as proposed by Levene). **DNA** must carry information from parent cell to daughter cell./ It must contain **information** for replicating itself./ It must be **chemically stable,** relatively unchanging/. However, it must be capable of **mutational change/**. Without mutations, there would be no **process of evolution**./ Many scientists were interested in **deciphering** /the structure of DNA,/ among them were Francis Crick, James Watson, Rosalind Franklin, and Maurice Wilkens. Watson /and Crick gathered all available **data** in an attempt to develop a model of DNA structure./ Franklin took **X-ray** diffraction photomicrographs of crystalline DNA extract/, the key to the puzzle. The data known at the time was that DNA/ was a long **molecule**, and proteins were helically coiled. units along the sides of the helix /(like the sides of a twisted ladder). The **strands** are complementary (deduced by Watson /and Crick from Chargaff's data, A pairs with T and C pairs with G,/ the pairs held together by hydrogen bonds). **Purines** are Adenine/ (A) and Guanine (G). Pyrimidines are /Cytosine (C) and Thymine (T). The bases are complementary/, with A on one side of the **molecule** /you only get T on the other side, similarly with G /and C. If we know the base sequence /of one **strand** we know its complement.
 * DNA** is a double helix,/ with bases to the center (like rungs on a ladder) and

__**Questions:**__ 1. Recall what DNA must carry, contain, and be. info from parents cell to daughters cell. info for replicating itself, and chemically stable 2. Clarify why Watson and Crick gathered data about DNA.so they could develop a model of DNA structure 3. Compare and contrast purines and pyrimidines.purines are blood cells and pyrimidines are white blood cells Most Challenging words 1.chargaff 2.nitrogenous 3.purines 4.deciphering 5.photomicrographs 6.helix 7.Guanine 8.Pyrimidines 9.Cytosine 10.sugar-phosphate

Passage: The Structure of DNA Erwin Chargaff analyzed/the nitrogenous bases in many different forms of life/, concluding that the amount of **purines** /does not always equal the amount of pyrimidines /(as proposed by Levene). **DNA** must carry information from parent cell to daughter cell./ It must contain **information** for replicating itself./ It must be **chemically stable,** relatively unchanging/. However, it must be capable of **mutational change/**. Without mutations, there would be no **process of evolution**./ Many scientists were interested in **deciphering** /the structure of DNA,/ among them were Francis Crick, James Watson, Rosalind Franklin, and Maurice Wilkens. Watson /and Crick gathered all available **data** in an attempt to develop a model of DNA structure./ Franklin took **X-ray** diffraction photomicrographs of crystalline DNA extract/, the key to the puzzle. The data known at the time was that DNA/ was a long **molecule**, and proteins were helically coiled. units along the sides of the helix /(like the sides of a twisted ladder). The **strands** are complementary (deduced by Watson /and Crick from Chargaff's data, A pairs with T and C pairs with G,/ the pairs held together by hydrogen bonds). **Purines** are Adenine/ (A) and Guanine (G). Pyrimidines are /Cytosine (C) and Thymine (T). The bases are complementary/, with A on one side of the **molecule** /you only get T on the other side, similarly with G /and C. If we know the base sequence /of one **strand** we know its complement.
 * DNA** is a double helix,/ with bases to the center (like rungs on a ladder) and

__**Questions:**__ 1. Recall what DNA must carry, contain, and be. info from parents cell to daughters cell. info for replicating itself, and chemically stable 2. Clarify why Watson and Crick gathered data about DNA.so they could develop a model of DNA structure 3. Compare and contrast purines and pyrimidines.purines are blood cells and pyrimidines are white blood cells