Which of the following structural characteristics is not normally observed in a dna duplex?
(a) purine-pyrimidine pairs
(b) external sugar-phosphate backbone
(c) uniform left-handed twist
(d) antiparallel strands

it’s lava came from an explosive eruption

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products