1. Which of the following statements about DNA is TRUE?

Question

a) DNA contains four bases, the pyrimidines (A and G) and the purines (C and T)

b) Covalent bonds between complementary base pairs hold the two strands of a double helix together

c) The two strands of a double helix run parallel to each other X

d) DNA is a polymer of nucleotides held together by peptide bonds

e) The 5’ end has a free phosphate and the 3’ end contains a free OH group

Answer 1

From deductive reasoning a) is false because C and T are pyramidines and A and G are purines. b) is false because complementary strands are held together by hydrogen bonding c) is false because the two strands run antiparallel. d) is false because DNA is held together by covalent bonds not peptide like in amino acids. Thus, e would be the correct answer.