This section contains multiple choice questions. Each question has 4 choices (a), (b), (c) and (d), out of which ONLY ONE is correct. The enzyme, which decomposes glucose to alcohol and \(\mathrm{CO}_{2}\) is (a) Invertase (b) Zymase (c) Diastase (d) Maltase

Enzymes are the indispensable biological catalysts that accelerate chemical reactions within the cells of living organisms. Their functions are highly specialized, each one tailored to catalyze a specific reaction or set of reactions. For example, enzymes play a crucial role in the metabolic process, aiding in the conversion of nutrients into energy and new cellular components. They achieve this by lowering the activation energy required for a reaction to proceed, thus increasing the rate of the reaction. Importantly, enzymes do this without being consumed or permanently altered, allowing them to repeatedly facilitate numerous cycles of a reaction.

In the context of our exercise, four different enzymes are mentioned. Each one has a specific function:

• Invertase catalyzes the hydrolysis of sucrose into glucose and fructose.
• Zymase accelerates the breakdown of glucose to produce ethanol and carbon dioxide.
• Diastase assists in the digestion of starch, converting it into maltose.
• Maltase breaks down maltose into two glucose molecules.

Understanding these functions allows us to identify the correct enzyme needed for a particular reaction, as was needed in the exercise's question regarding the decomposition of glucose.

Glucose decomposition is a biochemical process where glucose molecules are broken down to release energy. This process can take different pathways, depending on the organism and conditions, such as the presence or absence of oxygen. In aerobic conditions, glucose is fully oxidized to carbon dioxide and water through glycolysis, the Krebs cycle, and the electron transport chain, releasing ATP, the energy currency of the cell.

However, in anaerobic conditions or in our specific case, in the presence of the enzyme zymase, glucose can undergo fermentation. Fermentation is the process of glucose decomposition that occurs in the absence of oxygen, leading to different end products. For instance, in alcoholic fermentation, which commonly takes place in yeast cells, glucose is decomposed into ethanol and carbon dioxide. This reaction is pivotal in industries such as brewing and baking, where ethanol and carbon dioxide are desirable products.

In the exercise, students were asked to identify the enzyme that facilitates the decomposition of glucose into alcohol and carbon dioxide, which is a classic example of fermentation.

Zymase is a complex enzyme that is found in yeast and is crucial for the process of alcoholic fermentation. It is not a single enzyme but rather a collection of enzymes that work together to convert glucose into ethanol and carbon dioxide. Zymase performs this by first breaking down glucose into two molecules of pyruvate via the process of glycolysis. The pyruvate then undergoes decarboxylation (where CO2 is released), followed by the reduction step to form ethanol.

This biochemical process is not only fundamental in organisms such as yeast but also has huge economic significance. The production of alcoholic beverages, such as beer and wine, relies on the activity of zymase. Moreover, the carbon dioxide gas produced during fermentation causes bread to rise. Because it carries out fermentation, zymase is an excellent example of an enzyme that changes substrates without requiring oxygen, showcasing the diversity in enzymatic functions and their importance in different contexts, a key concept that students should grasp to understand the role of this enzyme.