Key Terms
Organism
T2 bacteriophage infecting E. coli.
Key result
F1 violet flowers x white flowers → all violet (F1); F2 ratio ~3 violet : 1 white. Conclusion: traits are transmitted fa
Direct evidence came later
Morgan and colleagues — used Drosophila melanogaster (fruit fly). Correlated microscopic chromosome observations with of
Method
Infect E. coli separately with each labeled batch.
Key experiment
Identified three classes of arginine mutants. Each class failed at a different step in the arginine biosynthesis pathway
R strain
Nonpathogenic, no capsule, rough colony appearance. S strain: pathogenic, has capsule (blocks phagocytosis), smooth colo
Conclusion
DNA — not protein — is injected and carries the hereditary information to produce new phage particles. Community accepte
During polymerization
Deoxynucleotide triphosphates (dNTPs) are used. Two terminal phosphate groups are released as pyrophosphate.
Result
One end of the strand has a free phosphate group at the 5' carbon (5' end); the other has a free hydroxyl group at the 3
Explanation
Complementary base pairing in the double helix.
Denaturation
High heat or certain chemicals break hydrogen bonds between complementary bases. Double-stranded DNA (dsDNA) → single- s
Single-stranded RNA viruses
Rhinoviruses (common cold), influenza viruses, Ebola virus. Double-stranded RNA viruses: rotaviruses (severe gastroenter
Genome
Total genetic content of a cell (all DNA). Gene: segment of DNA containing the instructional code for synthesizing a spe
Housekeeping genes
Constitutive genes necessary for basic cellular functions.
DNA supercoiling
DNA is twisted to fit inside the cell.