A common biological process that takes place in yeast cells is cellular respiration. During cellular respiration, yeast cells convert oxygen (O₂) and sugar into carbon dioxide (CO₂), water (H₂O), and ATP energy, which is essential for the cells' metabolic needs.
Let's look at the given options:
A. [tex]\( CO_2 + H_2O + \text{ATP energy} \rightarrow O_2 + \text{sugar} \)[/tex]
- This equation suggests that CO₂ and H₂O are combined using ATP energy to produce O₂ and sugar. This reaction does not describe cellular respiration. Instead, it more closely resembles the reverse process of photosynthesis, typically found in plants.
B. [tex]\( O_2 + \text{sugar} \rightarrow CO_2 + H_2O + \text{ATP energy} \)[/tex]
- This equation shows oxygen and sugar being converted into carbon dioxide, water, and ATP energy. This is the correct representation of cellular respiration in yeast cells. It matches the fundamental chemical equation for cellular respiration:
[tex]\[ C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP energy} \][/tex]
C. [tex]\( O_2 + \text{sugar} \rightarrow CO_2 + H_2O + \text{light energy} \)[/tex]
- This equation suggests that light energy is a product of the reaction, which is incorrect. Cellular respiration produces ATP, not light energy.
D. [tex]\( CO_2 + H_2O + \text{light energy} \rightarrow O_2 + \text{sugar} \)[/tex]
- This equation describes the process of photosynthesis, which typically occurs in plants, where carbon dioxide and water are converted into oxygen and sugar using light energy. This is not the correct process for yeast cells.
Given these explanations, the correct equation that represents a process taking place in yeast cells (cellular respiration) is:
[tex]\[ B. \ O_2 + \text{sugar} \rightarrow CO_2 + H_2O + \text{ATP energy} \][/tex]
Thus, the correct answer is:
[tex]\[ \boxed{2} \][/tex]
