USA Biology Olympiad (USABO) Practice Exam

What impact does the mutation found adjacent to β-galactoside have on the enzyme responsible for lactose transport?

1. It becomes less efficient at lower temperatures

2. It renders the enzyme sensitive to high temperatures

3. It increases lactose transport capacity

4. It decreases binding affinity to lactose

The correct answer is: It renders the enzyme sensitive to high temperatures

The mutation occurring adjacent to β-galactoside can lead to changes in the structural properties of the enzyme responsible for lactose transport. Specific mutations can cause the enzyme to be sensitive to temperature changes, which affects how well it functions. When enzymes undergo mutations, they may adopt a conformation that is less stable at elevated temperatures, leading to a loss of enzymatic activity or unfolding under stressful conditions. This sensitivity to high temperatures would indicate that the enzyme's effectiveness is compromised when exposed to heat, thus impairing its ability to facilitate lactose transport efficiently. Understanding this relationship is key, as temperature is a critical factor affecting enzyme activity. Enzymes generally have an optimal temperature range for activity, and deviations from this range can lead to decreased functionality. This highlights the importance of structural stability in enzymes, particularly in response to environmental conditions.