Question

What are two major advantages of enzyme catalysts in living organisms when compared with other simple chemical catalysts such as acids or bases?

Short answer

Enzymes are highly specific and efficient at physiological conditions compared to simple chemical catalysts like acids or bases.

Step-by-step solution

- Understand Enzyme Catalysts

Enzyme catalysts are biological molecules, usually proteins, that speed up chemical reactions in living organisms. They are extremely specific to the reactions they catalyze.

- Specificity of Enzymes

One major advantage of enzyme catalysts is their high specificity. Enzymes catalyze very specific biochemical reactions, reducing the likelihood of side reactions that can occur with less specific chemical catalysts like acids or bases.

- Efficiency of Enzymes

Another advantage is their efficiency in physiological conditions. Enzymes function optimally at the moderate temperatures and neutral pH levels that are characteristic of living organisms, whereas simple chemical catalysts often require extreme conditions.

Key concepts

enzyme specificity

Enzyme specificity means that enzymes only catalyze specific biochemical reactions. This is important because it reduces the chance of unwanted side reactions that can happen with less specific chemical catalysts like acids or bases.
Enzymes have an active site— a unique region that binds to a specific substrate (the molecule that the enzyme acts upon).
This specificity arises because the structure of the active site is complementary to the structure of the substrate, much like a key fits into a specific lock.
This unique feature is essential for the controlled and efficient functioning of metabolic pathways in cells.
For example:

• Lactase is an enzyme that specifically breaks down lactose into glucose and galactose.
• Amylase specifically breaks down starch into simpler sugars.

Without high specificity, cellular processes would slow down and potentially produce noxious byproducts.

biochemical reactions

Biochemical reactions are chemical reactions that occur inside living organisms. These reactions are crucial for sustaining life,
from breaking down food to generating energy and synthesizing biomolecules.
Enzymes speed up these reactions by lowering the activation energy—the energy needed to start a chemical reaction.
Without enzymes, these reactions would be too slow to sustain life.
An example includes the breakdown of glucose during cellular respiration to produce energy in the form of ATP.

• This process involves a series of enzyme-catalyzed steps that convert glucose into energy efficiently.
• Another example is photosynthesis in plants, where enzymes help convert carbon dioxide and water into glucose and oxygen under sunlight.

Enzymes make sure that these reactions happen quickly and efficiently, allowing organisms to thrive.

enzymatic efficiency

Enzymatic efficiency refers to the ability of enzymes to facilitate chemical reactions at rapid rates under mild conditions.
This sets them apart from simple chemical catalysts, which often need extreme conditions like high temperatures or strong acids/bases to work.
Enzymes operate optimally at moderate temperatures and neutral pH levels typical of living organisms. This is beneficial for survival, as it avoids damage to delicate cell structures.
The catalytic activity of enzymes can be measured by the turnover number, which indicates the number of substrate molecules converted per enzyme molecule per second.
Fast turnover means more product in less time, which is crucial for the organism's metabolism.
An example includes DNA polymerase, an enzyme that efficiently synthesizes new strands of DNA during cell division.

• One DNA polymerase can add thousands of nucleotides per second, ensuring quick and accurate DNA replication.

This efficiency keeps the organism healthy and thriving.