2_07 AP Free Response
1)
a.
b)
Temperature and pH affects an enzyme nearly the same way, though for
different reasons. First, the structure of an enzyme is very complex. The
basic structure of a protein is amino acids, tied together by peptide bonds,
which is formed by dehydration. The structure of the protein is important,
because bonds form within to create complex shapes that determines its
function, because a protein is like a three-dimensional lock.
If temperature was gradually increased, enzyme activity will increase
too, because increase in temperature means the thermal heat and that the
substrates are bouncing around faster and hitting the enzyme more often, thus
increasing the reaction rate of the enzyme. But the enzyme activity increases
until the temperature hits the optimal temperature. At the optimal
temperature, the enzyme denatures because the increase in thermal energy has
disrupted the bonds between the amino acids and destroying the shape of the
protein, which is essential to its function. If temperature is lowered from the
optimal level, though, the protein will regain its original shape.
If pH is increased, enzyme activity will also increase to an optimal pH
level. Enzyme activity increases because the gradual decrease of H+ ions
leaves the substrates little interference/attraction to the positive ion as it makes
its way to the enzyme. But past the optimal pH level, there will be too many
OH- ions in the surroundings which will bond with the H+ ions in the protein
and change the structure, and thereby denaturing the protein.
A controlled experiment that can be used is by taking an two separate groups
of enzyme, and adding the substrate. The first group of enzymes will be the
controlled group, with no increase in temperature or pH. The second group
will be the experimental group and it will gradually have an increase in pH
level or temperature, whichever is being tested. Both will be measured after
an increase in temperature or pH. The hypothesis being tested is that when the
temperature/pH level are increased, then the rate of the enzyme activity will
increase until it reaches an optimal point, and then it will decline because the
enzyme is being denatured.
Since both temperature and pH increase enzyme activity when they
increase until they hit an optimal temperature of pH level, then the same
experiment can be used for both.