Problem 32 - Chemistry Matter and Change

Question

Calculate How many moles of ATP would a yeast cell produce if 6 mol of glucose were oxidized completely in the presence of oxygen? How many moles of ATP would the yeast cell produce from 6 mol of glucose if the cell were deprived of oxygen?

Step-by-Step Solution

Answer

When 6 moles of glucose are oxidized completely in the presence of oxygen, yeast cells produce 228 moles of ATP through cellular respiration. In the absence of oxygen, yeast cells would produce only 12 moles of ATP from 6 moles of glucose through anaerobic fermentation.

Step 1: Determine the number of ATP molecules produced per mole of glucose

We know that there are approximately 38 ATP molecules produced per glucose molecule, so our equation looks like this: 1 mol glucose → 38 mol ATP

Step 2: Apply the stoichiometry to find the number of moles of ATP produced from 6 mol of glucose

Using the conversion factor, calculate the number of ATP moles produced from 6 mol of glucose: 6 mol glucose × \( \frac{38\:mol\:ATP}{1\:mol\:glucose}\) = 228 mol ATP Anaerobic condition (absence of oxygen): Under anaerobic conditions, yeast cells metabolize glucose through fermentation that produces only 2 ATP molecules per glucose molecule.

Step 3: Determine the number of ATP molecules produced per mole of glucose in anaerobic conditions

We know that there are approximately 2 ATP molecules produced per glucose molecule during anaerobic fermentation, so our equation looks like this: 1 mol glucose → 2 mol ATP

Step 4: Apply the stoichiometry to find the number of moles of ATP produced from 6 mol of glucose

Using the conversion factor, calculate the number of ATP moles produced from 6 mol of glucose during anaerobic fermentation: 6 mol glucose × \( \frac{2\:mol\:ATP}{1\:mol\:glucose}\) = 12 mol ATP In conclusion, when 6 moles of glucose are oxidized completely in the presence of oxygen, yeast cells produce 228 moles of ATP. In the absence of oxygen, yeast cells would produce only 12 moles of ATP from 6 moles of glucose.

Key Concepts

Yeast Metabolism

Yeast, a type of fungus, undergoes different metabolic processes depending on the presence or absence of oxygen. Yeast metabolism is fascinating because it can switch between aerobic and anaerobic pathways to adapt to the environment. This metabolic flexibility allows yeast to survive and thrive in various conditions.

• In the presence of oxygen, yeast prefers aerobic respiration, which is more efficient in terms of ATP production.
• In the absence of oxygen, yeast resorts to anaerobic fermentation, a less efficient way to produce energy but crucial for survival.

Understanding yeast metabolism is fundamental for industries such as baking and brewing, where specific conditions are manipulated to achieve desired results in bread and alcoholic beverages.

Aerobic Respiration

Aerobic respiration is the process by which cells convert glucose and oxygen into energy, usually in the form of ATP (adenosine triphosphate). It is a highly efficient method that maximizes the energy extracted from glucose. During aerobic respiration, one molecule of glucose can yield approximately 38 molecules of ATP.

• This process involves several stages including glycolysis, the citric acid cycle, and oxidative phosphorylation.
• Oxygen acts as the final electron acceptor, making the complete breakdown of glucose possible.

Due to its high ATP yield, aerobic respiration is the preferred pathway for yeast when oxygen is plentiful. It enables cells to harness maximum energy to fuel various biological functions and growth.

Anaerobic Fermentation

When oxygen is not available, yeast cells switch to anaerobic fermentation to generate energy. Although less efficient than aerobic respiration, this process is vital for yeast cells as it allows them to survive when oxygen is scarce. Anaerobic fermentation results in the production of only 2 molecules of ATP per glucose molecule.

• This process converts glucose into ethanol and carbon dioxide, which are important byproducts in industries like brewing and winemaking.
• Fermentation is quick but energetically inefficient compared to its aerobic counterpart.

Despite its low ATP yield, anaerobic fermentation is crucial for energy production under anaerobic conditions, helping yeast sustain its activities when oxygen is unavailable.