Contrast the contributions of Pauling and Ingram to our understanding of the genetic basis for sickle-cell anemia.

The study of biochemical mutants in organisms such as Neurospora has demonstrated that some pathways are branched. The data shown in the following table illustrate the branched nature of the pathway resulting in the synthesis of thiamine:Growth Supplement _Mutation Minimal Medium Pyrimidine Thiazole Thiaminethi-1 − − + +thi-2 − + − +thi-3 − − − +Why don't the data support a linear pathway? Can you postulate a pathway for the synthesis of thiamine in Neurospora?

Why is an alteration of electrophoretic mobility interpreted as a change in the primary structure of the protein under study?

Using sickle-cell anemia as an example, describe what is meant by a molecular or genetic disease. What are the similarities and dissimilarities between this type of a disorder and a disease caused by an invading microorganism?

Hemoglobins from two individuals are compared by electrophoresis and by fingerprinting. Electrophoresis reveals no difference in migration, but fingerprinting shows an amino acid difference. How is this possible?

Several amino acid substitutions in the α and β chains of human hemoglobin are shown in the following table. Hb Type Normal Amino Acid Substituted Amino Acid Hb Toronto Ala Asp (α-5) HbJ Oxford Gly Asp (α-15)Hb Mexico Gln Glu (α-54)Hb Bethesda Tyr His (β-145)Hb Sydney Val Ala (β-67)HbM Saskatoon His Tyr (β-63)Using the code table (Figure 13.7), determine how many of them can occur as a result of a single-nucleotide change.