Cell Energetics: Enzyme Role in
Biological Reactions
Name: Ece Cansu Tan
Student Number:
Lab Partner’s Name: Hadil Sayed
Course Code: BIOL 1103
Lab Section: Tuesday AM
This study source was downloaded by from CourseH on :52:58 GMT -05:00
Introduction:
Enzymes are proteins that are imp...
Enzymes are proteins that are important for many biological processes to sustain life and they
act as catalysts in biological reactions to speed up the rate of the reaction by lowering the
activation energy. The enzyme remains unaltered during the reaction and is free to repeat the
process with new substrate molecules (Biology Department, 2014). As a result, one enzyme
molecule can convert many molecules into many product molecules (Biology Department,
2014). The fastest reactions include reactions catalyzed by enzymes. In absence of enzymes,
these same reactions are among the slowest that have ever been measured, some with half-
times approaching the age of Earth. (Wolfenden&Snider, 2001). It is very important to
understand their biological role, because many vital processes depend on enzyme’s activity
such as cells in humans’ body contain many different enzymes, and their activities are important
for cells to survive.
In the enzyme-catalyzed reaction, the rate of reaction is measured as the amount of substrate
converted to product per unit time (Biology Department, 2014). Since binding of the substrate to
the enzyme is a random event resulting from chance collisions between the two, the rate of the
reaction depends on concentration of each of these two molecules in the reaction. (Biology
Department, 2014). When the concentration of the enzyme is constant, the reaction rate
increases as the concentration of substrate increases. As well as when substrate concentration
is constant, the rate of reaction increases as the enzyme concentration increases.
Other factors such as pH and temperature can also affect the rate of the reaction (Biology
Department, 2014). At high temperatures as the temperature increases, the kinetic energy of the
molecules increases, therefore causing the rate of the reaction to be faster because there is
more frequent collisions between the enzyme and substrate. However there is a point at which
the kinetic energy is so great that it disturbs the weak hydrogen bonds and hydrophobic
interactions that hold the secondary and tertiary structure of the enzyme. (Biology Department,
2014). This can cause the shape of the enzyme to change and prevents the substrate binding
and therefore substrate cannot be converted into product. The pH of a reaction can also affect
the secondary and tertiary structure of an enzyme and hence the reaction rate (Biology
Department, 2014).
This study source was downloaded by 100000851296032 from CourseHero.com on 11-01-2022 13:52:58 GMT -05:00
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