Question

the graphs show the activity of an enzyme at different ph levels and temperatures. what can be inferred by looking at the two graphs? the enzyme becomes inactive at a ph of 7 and a temperature of 25°c. the enzyme gets completely used up at a ph of 9 and a temperature of 30°c. the enzyme works only at a ph of 6 and a temperature of 20°c. the enzyme works best at a ph of 6 and a temperature of 20°c.

Explanation:

1. Analyze the pH - enzyme activity graph: The curve peaks around pH 6 (between 5 - 7), indicating the highest enzyme activity at this pH.
2. Analyze the temperature - enzyme activity graph: The curve peaks around 20°C (near 25°C but before the sharp decline), showing the highest activity here.
3. Evaluate other options:

• Option 1: At pH 7, enzyme activity is not zero (graph shows activity), and at 25°C, activity is still high (before the drop), so incorrect.
• Option 2: Enzymes are not "used up", they can be reused; at pH 9 and 30°C, activity is low but not due to being used up, incorrect.
• Option 3: Enzyme works at other pH/temperatures (just less effectively), not "only" at pH 6 and 20°C, incorrect.
• Option 4: Matches the peak activity points from both graphs, correct.

Answer:

D. The enzyme works best at a pH of 6 and a temperature of 20°C.