Question

students conduct an experiment on how ph impacts bromelain (enzyme in pineapple juice) activity on gelatin (protein). steps: prepare gelatin, add water/pineapple juice to test tubes, refrigerate, record observations (table 1: gelatin state). a graph shows bromelain activity (%) vs ph. question: what can be inferred about gelatin that remained liquid? options: ph 8–10, >10, 3–7, <2.

Explanation:

To determine the pH of the gelatin that remained liquid, we analyze the graph of bromelain activity (an enzyme in pineapple juice that breaks down gelatin). When gelatin remains liquid, it means bromelain was active enough to break it down. From the graph, bromelain activity is high (so gelatin breaks down, remains liquid) when pH is within 3 - 7? Wait, no—wait, the control (water) gelatin solidifies. When pineapple juice is added, if gelatin remains liquid, bromelain is active. Looking at the graph: at pH 2, activity is 20%? Wait, no, the x - axis is bromelain activity (%), y - axis is pH. Wait, the points: at pH 0, activity 0; pH 2, activity ~20? No, wait the graph: when pH is 8 - 10, bromelain activity is low (so gelatin would solidify, since enzyme is inactive). When pH is 3 - 7, bromelain activity is high? Wait, no, the graph shows that at pH 10, activity is 0 (gelatin solidifies, as in control). At pH 8, activity is low. At pH 6 - 2, activity is high? Wait, the option "It has a pH within the range of 3 to 7"—wait, no, let's re - examine. The gelatin that remained liquid: in the experiment, when bromelain is active (enzyme works), gelatin breaks down (remains liquid). From the graph, bromelain activity is high when pH is between ~2 - 8? Wait, the options:

• Option 1: pH within 8 - 10: at pH 10, activity is 0 (gelatin solidifies, so this is wrong).
• Option 2: pH higher than 10: activity is 0 (gelatin solidifies, wrong).
• Option 3: pH within 3 - 7: when pH is in 3 - 7, bromelain activity is high (so gelatin breaks down, remains liquid—this matches the observation where with pineapple juice (containing bromelain) at suitable pH, gelatin remains liquid.
• Option 4: pH lower than 2: at pH 2, activity is ~20? Wait, no, the graph at pH 2 has some activity, but the option "within 3 - 7" is more accurate as the main range where enzyme is active enough to keep gelatin liquid. So the correct inference is that the gelatin with liquid state has pH in 3 - 7.

Answer:

It has a pH within the range of 3 to 7.