Domain: Natural Science — Biochemistry & Molecular Biology
Target concept: Batch enzyme assay, detecting phosphate release by blue color development (molybdenum-based)

Video generation prompt: On the lab bench, two clear test tubes containing fructose-1,6-bisphosphate: the left one contains the active enzyme, and the right one contains the heat-denatured enzyme. After brief incubation, a molybdate-based phosphate detection reagent was added.

Evaluation guide:
(i) Target concept: Enzyme activity dependence on conformational integrity, demonstrated via differential phosphate detection.
Minimum mechanism: Fructose-1,6-bisphosphate must be present as substrate; active enzyme must retain native structure to cleave it; heat-denaturation must irreversibly abolish activity; molybdate reagent must react *only* with free phosphate (not substrate or enzyme) to yield blue color; blue formation requires both phosphate *and* reagent; neither alone suffices.
(ii)Storyline: [Frame 0–2] Static lab bench view: two empty test tubes placed left/right. [Frame 3–4] Fructose-1,6-bisphosphate solution added to both tubes (liquid level identical). [Frame 5–6] Active enzyme (e.g., vial labeled “FBPase”) dispensed into left tube; heat-denatured enzyme (e.g., vial labeled “boiled FBPase”) into right tube. [Frame 7] Brief static “incubate” cue (e.g., timer overlay or hand resting). [Frame 8] Molybdate reagent added to left tube → immediate visual focus on left tube. [Frame 9] Reagent added to right tube → immediate visual focus on right tube. [Frame 10] Final frame holds both tubes: left shows homogeneous blue solution, right shows colorless/pale yellow solution. All actions occur from fixed frontal bench perspective; no occlusion; lighting constant; color development visible only after reagent contact.

Manual:
Experimental Procedure
1. Place two identical test tubes side-by-side on lab bench.
2. Add fructose-1,6-bisphosphate solution to both tubes.
3. Add active enzyme to left tube; add heat-denatured enzyme to right tube.
4. Incubate briefly (e.g., 2 min at room temp).
5. Add molybdate-based phosphate detection reagent to both tubes.
Observation of Experimental Phenomena
Left tube (active enzyme) develops uniform blue color; right tube (heat-denatured enzyme) remains colorless or pale yellow — no blue.
Summary of Experimental Principles
Active phosphatase enzyme hydrolyzes fructose-1,6-bisphosphate, releasing inorganic phosphate; phosphate reacts with molybdate reagent to form blue phosphomolybdate complex. Heat-denatured enzyme lacks catalytic activity → no phosphate release → no blue color.

Prompt Grounding rubric:
level_1: No test tubes are shown; or the fructose-1,6-bisphosphate solution never appears; or the active-enzyme tube and the heat-denatured-enzyme tube are not distinguishable from each other; or the molybdate-based reagent is never added; or the two tubes are never shown together in the same shot.
level_2: The two tubes appear together, but at least one required element is missing: no clear label or visual cue distinguishing the active-enzyme tube from the heat-denatured tube; fructose-1,6-bisphosphate solution is missing from one or both tubes; or the molybdate reagent is added to only one of the two tubes.
level_3: Both tubes contain fructose-1,6-bisphosphate solution and sit next to each other on the bench; one is clearly marked or shown as containing active enzyme (e.g., a 'FBPase' label or an unheated vial), the other as heat-denatured (e.g., a 'boiled FBPase' label or a vial coming off a hot plate); the molybdate-based reagent is added to both tubes after a brief incubation is implied (e.g., a pause, a timer cue, or a label reference to a short wait).
level_4: All conditions for score 3 are met, and the camera holds a single fixed lab-bench framing with no jump cuts; both tubes stay visible in frame before, during, and after the reagent is added; nothing occludes either tube; the reagent is shown entering each tube from a dropper or pipette tip rather than simply appearing in the liquid.
level_5: All conditions for score 4 are met, and the active-enzyme tube sits on the left with the heat-denatured tube on the right, matching the prompt exactly; the reagent is added to both tubes together or in a clear left-then-right sequence; there is no ambiguity at any point about which tube is which, whether the substrate solution is present, or whether the reagent has reached each tube.

Scientific and Causal Correctness rubric:
level_1: Neither tube shows any color change after the reagent is added; or both tubes end up the same color (e.g., both turn blue, or both stay colorless); or a blue color is visible in a tube before the molybdate reagent has been added to it.
level_2: Only one tube changes color, but it is the wrong one (the heat-denatured tube turns blue while the active-enzyme tube stays colorless or pale), reversing the expected outcome; or blue color appears the instant the reagent touches the liquid with no sense that any incubation preceded it.
level_3: Blue color develops only in the active-enzyme tube after the reagent is added; the heat-denatured tube stays colorless or pale yellow; a short incubation is implied before the reagent goes in; the blue appears within the liquid itself rather than as a film on the surface or a stain on the glass.
level_4: All conditions for score 3 are met, and the blue in the active tube looks even and fully mixed through the liquid rather than patchy; the heat-denatured tube shows no trace of blue anywhere: not at the meniscus, the bottom, or the tube wall; there are no stray blue specks or streaks in the denatured tube; the color difference between the two tubes is easy to tell apart under the same lighting.
level_5: All conditions for score 4 are met, and the blue color in the active tube only appears after the reagent is added, never before or during mixing; the blue is noticeably more intense and even than any background tint in the scene; the heat-denatured tube shows no discernible blue tint anywhere, consistent with no phosphate having been released by the denatured enzyme.

Spatiotemporal Consistency rubric:
level_1: A tube suddenly appears in a different spot or at a different size with no motion in between; one of the two tubes is absent from a frame and then present again later; the reagent liquid appears inside a tube with no visible dropper or pour reaching it; the bench lighting jumps between bright and dark with no fade.
level_2: A tube shifts sideways by more than its own width between shots with no visible cause; the reagent dropper enters the frame from off-screen without a continuous path down to the tube; the bench surface or background looks different from one moment to the next during the incubation pause.
level_3: Both tubes stay in the same spot and fully visible the whole time; the reagent is shown moving continuously from the dropper tip into the tube; nothing passes through another object; the lighting stays even through the addition and color-change steps; the incubation pause is shown as a steady held shot or a smooth timer rather than a jump cut.
level_4: All conditions for score 3 are met, and the dropper's motion is steady rather than trembling or skipping; the reagent stream enters the tube without splashing back out or bouncing; the tube rims and any labels line up consistently from frame to frame; shadows and highlights stay consistent with one steady light source.
level_5: All conditions for score 4 are met, and there is no blurring that makes it hard to tell the tubes or their colors apart; the viewpoint holds steady with no shimmering or wobble; the two tubes keep the same size and spacing relative to each other throughout; the whole sequence from incubation to reagent addition to color appearing plays out as one continuous, uncut, unfrozen shot.