During cooling, the kinetic energy of the molecules falls. why does this happen?
a.
the motion of the molecules increases.
b.
the motion of the molecules slows down.
c.
the van der waals forces between molecules decrease.
d. the forces of attraction between the molecules are overcome.

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."

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