Video Transcript
In the diagram provided, a section
is labeled with a question mark. This is where the substrate will
bind. What is the scientific term given
to this part of the enzyme?
In this question, we are presented
with a diagram showing an enzyme and a substrate. Our body constantly needs to break
down large molecules into smaller ones or build up large molecules from smaller
ones. But the chemical reactions that
break down or build up these molecules can sometimes be very slow. An enzyme is a biological catalyst
that speeds up the rate of such reactions without being used up. Let’s have a look at an
example.
When we eat food, we might ingest
large carbohydrates like starch. Starch is too large to be taken up
by the body cells. First, it has to be broken down
into smaller molecules in the digestive system. To aid in this process, our body
produces amylase, an enzyme which helps to break down starch into smaller
sugars. To do that, the substrate, in this
case starch, has to bind to amylase in the enzyme’s highly specific active site to
build an enzyme–substrate complex.
Every enzyme is very specific about
which substrates it will bind to. So the substrate, or substrates,
must be complementary to the enzyme’s active site in order to bind correctly and
form this enzyme–substrate complex. After the enzyme has catalyzed the
reaction, it will release products. In our example, the products would
be maltose and a shorter starch molecule.
In our diagram, the question mark
is pointing to the place where the substrate and enzyme join together. We know that the substrate will fit
into the enzyme at the enzyme’s active site. Therefore, the answer to our
question is active site.
