Video Transcript
Which of the following names is
given to the class of biological catalysts? (A) Enzymes, (B) substrates, (C)
minerals, (D) gametes, or (E) alleles.
A catalyst is a substance that
changes the rate of a reaction without undergoing a permanent chemical change. There are a number of biological
catalysts that each have an important role in the human body. Lactase is one example of a
biological catalyst. It serves an important role in
breaking down lactose. Lactose is a large sugar molecule
which is difficult for our bodies to digest. So it needs to be broken down into
smaller sugars. This process on its own is very
slow. That’s where lactase comes in. Lactose can bind to the catalyst
lactase, which then breaks the lactose into smaller sugars.
The overall process of breaking
lactose into smaller sugars using lactase is very fast. So lactase has changed the rate of
the reaction. In addition, once the reaction is
complete, lactase looks exactly the same as it did before the reaction began. So, although lactase participated
in the reaction, it did not undergo a permanent chemical change. This property of catalysts makes
catalysts particularly useful in reactions. As lactase is unchanged by the
chemical reaction, it can be used again and again to break more and more lactose
molecules.
Lactase is just one of many
biological catalysts. Amylase is another biological
catalyst that is used to break down starches. Lipase helps to break down lipids,
and protease helps to break down proteins. All of these biological catalysts
are classified as enzymes. Enzymes are large complex
structures, and each type of enzyme serves a different function in the body. However, they all have the same
general purpose: speeding up chemical reactions. So the name given to the class of
biological catalysts is answer choice (A) enzymes.
