Yeast have mitochondria and can perform cellular respiration. What would you expect to be consumed and produced during the process of cellular respiration in yeast?
a. Glucose and O2 consumed; CO2, H2O, and energy produced.
b. Glucose, H2O, CO2, and energy consumed; O2 produced.
c. CO2 and H2O consumed; glucose, O2, and energy produced.
d. CO2 and energy consumed; H2O, O2, and energy produced.
The correct answer and explanation is :
The correct answer is:
a. Glucose and O2 consumed; CO2, H2O, and energy produced.
Explanation:
Cellular respiration is a process in which cells break down glucose (or other nutrients) in the presence of oxygen to produce energy. This process takes place in the mitochondria of eukaryotic cells, including yeast, and can be summarized by the following chemical equation:
[
\text{C}_6\text{H}_12\text{O}_6 \, (\text{glucose}) + 6 \, \text{O}_2 \, (\text{oxygen}) \longrightarrow 6 \, \text{CO}_2 \, (\text{carbon dioxide}) + 6 \, \text{H}_2\text{O} \, (\text{water}) + \text{energy (ATP)}
]
1. Glucose Consumption:
The primary fuel for cellular respiration is glucose, which is broken down through a series of enzymatic reactions. In the first step, known as glycolysis, glucose is split into two molecules of pyruvate, and a small amount of ATP is produced. This process occurs in the cytoplasm. Pyruvate is then transported into the mitochondria, where it undergoes further oxidation in the Krebs cycle, producing more ATP, NADH, and FADH2.
2. Oxygen Consumption:
Oxygen plays a critical role as the final electron acceptor in the electron transport chain, which is the final step of cellular respiration. In this step, electrons are transferred through protein complexes embedded in the inner mitochondrial membrane. Oxygen combines with electrons and hydrogen ions (protons) to form water. Without oxygen, the electron transport chain would not function, and ATP production would cease.
3. Carbon Dioxide Production:
During the Krebs cycle, carbon atoms from glucose are released as carbon dioxide. The carbon atoms in glucose are oxidized and eventually exhaled as CO2, which is then expelled from the yeast cell into the surrounding environment.
4. Water Production:
Water is produced as a byproduct during the final stages of cellular respiration, particularly in the electron transport chain, where oxygen accepts electrons and combines with protons.
5. Energy (ATP) Production:
The ultimate goal of cellular respiration is the production of ATP, the molecule used for cellular energy. ATP is produced through substrate-level phosphorylation in glycolysis and the Krebs cycle, and oxidative phosphorylation in the electron transport chain.
Therefore, the correct answer reflects that glucose and oxygen are consumed, while carbon dioxide, water, and energy (ATP) are produced during cellular respiration in yeast.