Domain: Healthcare — Pathophysiology
Target concept: Cellular Morphological Changes in Free Radical Damage

Video generation prompt: Hydrogen peroxide (a free radical generator) was added to cultured hepatocytes, and changes in cell morphology and membrane integrity were observed under a light microscope.

Evaluation guide:
(i) Target concept: Free radical–induced plasma membrane damage in hepatocytes visualized via light microscopy.
Minimum mechanism: Hydrogen peroxide must enter aqueous culture medium → generate reactive oxygen species → initiate lipid peroxidation cascade → compromise membrane fluidity and integrity → manifest as loss of cell spreading, blebbing, and intercellular gap formation, all observable without staining in phase-contrast optics.
(ii)Storyline: Frame 1–3: Static microscope view of healthy hepatocyte monolayer (spread, polygonal, sharp borders). Frame 4–6: Dropper descends and contacts medium surface (visible meniscus perturbation). Frame 7–10: Same field-of-view reappears showing progressive morphological deterioration: first loss of spreading (rounding), then emergence of blebs, then visible gaps between adjacent cells, all confined to the region of droplet impact; no off-target changes; no reversal; no extraneous events (e.g., no bubbling, no precipitation, no color shift). Perspective is fixed light-microscope eyepiece view; full dish rim always visible to anchor spatial context; depth-of-field keeps cells sharply focused while background remains uniformly blurred.

Manual:
Experimental Procedure
1. Place cultured hepatocytes in a glass-bottom dish under light microscope.
2. Add one drop of hydrogen peroxide solution to the dish.
3. Observe hepatocyte morphology before and after addition.
Observation of Experimental Phenomena
Before: Hepatocytes appear spread, polygonal, with smooth, continuous plasma membranes and sharp borders.
After: Hepatocytes show rounding, membrane blebbing, and loss of membrane continuity — indicating free radical–induced membrane damage.
Summary of Experimental Principles
Hydrogen peroxide generates hydroxyl radicals that peroxidize lipid membranes, disrupting hepatocyte plasma membrane integrity and causing characteristic morphological degeneration observable by light microscopy.

Prompt Grounding rubric:
level_1: No dish of cultured hepatocytes is shown; no hydrogen peroxide dropper or bottle appears; there's no light-microscope view at all; none of the three key elements (the dish, the peroxide source, and the microscope view) show up anywhere in the clip.
level_2: At least one of the three elements (dish, dropper, microscope view) appears, but not in a coherent sequence: e.g., the dropper appears without any dish in view, or the microscope view shows cells that never connect to the dish being treated; there's no clear before/after distinction in the shot.
level_3: The hepatocyte dish, the hydrogen peroxide source, and a light-microscope field of view are all present, and the sequence shows a baseline view of cells, then peroxide added to the dish, then the same dish observed again under the microscope, but either the before- or after-view is missing visible cells, or the peroxide never appears to actually touch the dish.
level_4: Everything required for score 3 holds, and in addition the dropper tip is positioned directly over the dish and the microscope view stays centered on the dish; the sequence runs unambiguously from baseline cells, to the dropper touching the dish, to a post-contact microscope view of that same dish; no object swaps identity or jumps into the scene from nowhere between these stages.
level_5: Everything required for score 4 holds, and in addition the dropper visibly makes contact with the liquid surface in the dish (a visible dimple in the surface or a merging droplet); the microscope view keeps the same framing (the same cluster of cells, the same dish-edge position) in both the before and after shots; no unrelated object enters or leaves the frame partway through the sequence.

Scientific and Causal Correctness rubric:
level_1: No morphological change appears at all: the cells look the same before and after, keeping their sharp borders and even texture throughout, with nothing suggesting membrane damage.
level_2: Some change happens, but not the right kind: e.g., the cells shrink uniformly with no blebbing, or they burst apart into scattered debris (not how hydrogen-peroxide-driven free-radical damage typically looks), or the cells change color (blue, red), which isn't something unstained light microscopy would show.
level_3: The post-treatment view shows one clear sign of free-radical membrane damage: either the cell borders turn fuzzy and indistinct, or some cells appear rounded/blebbed, but not both; the baseline view shows fully spread, sharp-edged, smooth-membraned cells beforehand.
level_4: The baseline view shows a confluent layer of spread, sharp-edged, smooth-membraned cells; the post-treatment view shows at least two of these changes together: rounding (loss of spreading), visible blebs on the membrane, or visible gaps opening up between neighboring cells, with nothing contradictory like lysis debris, vacuole formation, or unexplained pigment.
level_5: Building on the 4-point bar, the damaged appearance is confined to the cells in the region where the droplet actually landed: every cell in that region shows at least one sign of damage, and cells clearly outside that region still look healthy and unaffected.

Spatiotemporal Consistency rubric:
level_1: The dish disappears and reappears between frames; the microscope view suddenly jumps to a different zoom level or orientation; the dropper teleports from one spot to another with no visible motion; the lighting swings from bright to dark between consecutive frames; the cells' positions jump with no motion connecting them.
level_2: The dish rotates or resizes in a way nothing in the scene explains; the microscope view pans or zooms with no mechanical reason given; the dropper approaches the dish but then the actual contact isn't connected to that approach by continuous motion; clusters of cells flicker in and out between frames.
level_3: The dish stays in the same place throughout; the dropper moves continuously toward the dish and makes contact; the microscope's framing and focus stay the same; no cell appears to teleport; the lighting and the direction of any shadows stay the same across the whole clip.
level_4: Building on the 3-point bar, the dropper's descent toward the dish looks physically reasonable (a steady vertical approach, not a sudden snap to contact); the change in cell morphology unfolds gradually across the clip rather than happening in a single instantaneous jump; the dropper is never shown passing behind the dish's edge in a way that breaks depth continuity.
level_5: Building on the 4-point bar, the moment of contact shows a visible, gradual deformation of the liquid surface rather than an instant change; the morphological breakdown of the cells (rounding, blebbing, gaps opening between cells) clearly begins only after that contact and keeps progressing smoothly over the following seconds, without ever reversing partway or freezing and jumping ahead.