Question

6. Which of the following discoveries provided a critical clue to Watson and Crick in solving the structure of DNA? (1 point)

the Hershey-Chase experiment
Griffith’s transformation experiment
Chargaff’s base ratios
Miescher’s isolation of DNA
7. A DNA strand with the sequence A-T-T-G-C-T would be complementary to which of the following? (1 point)
T-A-T-G-G-A
T-A-A-C-G-A
C-A-A-T-A-G
G-C-C-A-T-C
8. DNA from one species differs from the DNA of another species in its _____. (1 point)
base ratios
sugars
phosphate groups
all of the above

Answer 1

1. double helix model was proposed after getting the clue from chargaff rule purines = pyramidines 2. A = T ( this means A pairs with T) G = C (this means G pairs with C) A DNA strand with the sequence A-T-T-G-C-T is T-A-A-C-G-A 3. In all the species the nucleic acid is made of phosphate , sugar , nitrogenous base (A,T,C,G) only the number purines and pyrimidines vary.