Model Food Breakdown
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Middle School Life Science › Model Food Breakdown
A teacher shows two models of the same food entering an organism.
Model A: Food enters → food breaks into smaller molecules → smaller molecules rearranged into new molecules that become part of the organism.
Model B: Food enters → food is shown as the same molecule the whole time → the model labels the end result as “energy only.”
Which statement about food breakdown is supported by the evidence in Model A compared with Model B?
Reminder: digestion breaks down and rearranges food molecules.
Food molecules are rearranged into new molecules after being broken down, so digestion changes molecules rather than leaving them unchanged.
Digestion is mostly about turning food into energy, so showing molecules after digestion is unnecessary.
Food molecules disappear during digestion, which is why Model B does not show any molecules at the end.
If a model shows more pieces after digestion, it means the organism created new matter during digestion.
Explanation
The core skill in modeling food breakdown is comparing different models to determine which provides better evidence for digestion's effects. Digestion breaks food into smaller molecules, a process that occurs internally to extract usable parts. These are then rearranged into different molecules, not destroyed, for incorporation into the organism. Models highlight this by contrasting initial and final states, showing transformation without loss. A misconception is that digestion primarily produces energy without molecular outcomes, but accurate models include rearranged molecules. Breaking down food renders its materials suitable for cellular processes. Ultimately, this enables organisms to sustain themselves by repurposing food matter.
A class is comparing four simplified models of food entering an organism and changing inside it. In all four, the food starts as one large molecule outside the organism.
Which model shows the best evidence that digestion breaks food molecules into smaller molecules and then rearranges them (instead of destroying them), based on a clear before-and-after comparison?
Reminder: digestion breaks down and rearranges food molecules.
Inside the organism, the food is shown as the same large molecule unchanged, just moving to a different place.
Inside the organism, the food is shown turning directly into a lightning-bolt symbol labeled “energy,” with no molecules shown afterward.
Inside the organism, the food is shown as several smaller molecules, and later those smaller molecules are shown combined in a new arrangement that becomes part of the organism.
Inside the organism, the food is shown as tiny crumbs only, and then the crumbs vanish with an arrow labeled “gone.”
Explanation
The core skill in modeling food breakdown is evaluating models to find the best representation of digestion's effects on molecules. Digestion breaks food into smaller molecules inside the organism, turning large structures into manageable pieces through enzymatic action. These molecules are rearranged, not destroyed, to form new compounds that integrate into the organism's body. Models illustrate this by comparing initial large molecules to subsequent smaller ones that are reorganized, emphasizing conservation of matter. A misconception is that food simply vanishes or turns into energy without molecular changes, but accurate models show ongoing molecular presence. Breaking down food enables cells to rearrange materials for energy and growth. In general, this process makes food's components accessible, allowing organisms to thrive by reusing matter efficiently.
A student draws a model of what happens to a bite of food. The model shows: (1) a piece of food entering an organism, (2) the food being broken down into smaller pieces inside, and (3) the smaller pieces being rearranged into new molecules that become part of the organism. Which statement about food breakdown is supported by the model and its before-and-after comparison, using evidence from what is shown?
Reminder: digestion breaks down and rearranges food molecules.
Digestion mainly turns food into energy, so the molecules do not matter after the food is eaten.
Food stays the same molecules; it only changes location as it moves through the organism.
Food molecules disappear after digestion, so there is less matter inside the organism.
Digestion breaks food into smaller molecules and rearranges them into different molecules that can become part of the organism.
Explanation
The core skill in modeling food breakdown is understanding how digestion transforms food into usable materials for an organism. Digestion breaks food into smaller molecules by separating the large molecules in food through chemical processes in the digestive system. These smaller molecules are then rearranged into new molecules that the organism can use, rather than being destroyed or lost. Models show this change by illustrating a before-and-after comparison, where large food molecules enter and are depicted as broken down and reorganized into body molecules. A common misconception is that food disappears after digestion, but actually, the matter is conserved and transformed. Breaking down food into smaller molecules allows cells to access and utilize these building blocks for growth and repair. Ultimately, this process ensures that the materials from food become integrated into the organism's structure, supporting its survival and function.
A model shows a piece of food entering an organism. Inside, the model shows the food first broken into smaller molecules. Next, it shows those smaller molecules rearranged into molecules that become part of the organism’s body. Which prediction about breakdown is supported by the model if the food were not broken down into smaller molecules?
Reminder: digestion breaks down and rearranges food molecules.
It would be harder for the organism to rearrange the food into new molecules, because the model shows rearrangement happening after smaller molecules are made.
Nothing would change except the food would provide less energy, since digestion is only about energy.
The food molecules would disappear, because breakdown is what keeps matter from vanishing.
The food molecules would still be rearranged into new body molecules without needing to be broken down first.
Explanation
The core skill in modeling food breakdown is making predictions based on models about what happens if digestion steps are altered. Digestion breaks food into smaller molecules, a crucial step for further processing inside the organism. These molecules are then rearranged into usable forms, not destroyed, to build body structures. Models show this by depicting sequential changes, from breakdown to rearrangement, highlighting dependencies. A misconception is that breakdown is unnecessary for rearrangement, but models indicate it's foundational. Breaking down food ensures materials are in a form cells can manipulate. Generally, this enables organisms to efficiently use food for growth and energy needs.
A student’s model shows a sandwich entering an organism. The model then shows the sandwich broken into smaller molecules, and later shows those smaller molecules rearranged into molecules that become part of the organism’s body. Which piece of evidence from the model best supports the idea that molecules are rearranged, not destroyed, during digestion?
Reminder: digestion breaks down and rearranges food molecules.
The model shows the sandwich getting smaller as it moves through the organism.
The model shows the same smaller molecules after breakdown being used again in a different arrangement to make new molecules in the organism.
The model labels the stomach as the place where digestion happens.
The model shows the sandwich being chewed into pieces before it is swallowed.
Explanation
The core skill in modeling food breakdown is identifying evidence in models that supports molecular rearrangement during digestion. Digestion breaks food into smaller molecules, such as breaking a sandwich into basic nutrients through digestive juices. These smaller molecules are rearranged into different molecules for the organism's use, ensuring no matter is destroyed. Models depict this by showing the progression from intact food to broken-down pieces that are then reassembled into body parts. A misconception is that digestion only physically reduces size without chemical changes, but models prove rearrangement occurs. Breaking down food provides cells with raw materials they can use directly. Overall, this makes food's matter usable, promoting the organism's health and development.
Two students make before-and-after models of the same snack entering an organism.
Model 1: A large food molecule enters the organism. Inside, it is shown as several smaller molecules. Later, those smaller molecules are shown connected in a new arrangement that becomes part of the organism.
Model 2: A large food molecule enters the organism. Inside, it is shown as the same large molecule, only drawn smaller. Later, it is shown as “energy” with no molecules shown.
Which claim about digestion is incorrect based on the evidence in the models and the idea that digestion breaks down and rearranges food molecules?
Food molecules can be rearranged into different molecules that become part of the organism.
A before-and-after model can show that the molecules are changed, not just moved.
Digestion makes the food molecules disappear completely, so no molecules remain after digestion.
Digestion can break food into smaller molecules inside the organism.
Explanation
The core skill in modeling food breakdown is using evidence from models to identify correct and incorrect claims about digestion. Digestion breaks food into smaller molecules, enabling the body to process complex foods like snacks into simpler components. Importantly, these molecules are rearranged into new forms that become part of the organism, not destroyed, preserving the matter. Models demonstrate this by showing before-and-after states, where molecules are broken down and then reconfigured, providing evidence of transformation. One misconception is that digestion makes molecules vanish into energy, but models reveal they persist in new arrangements. Breaking down food makes its materials usable by cells for building tissues and performing functions. This generalization highlights how digestion supports the organism's ability to grow and maintain itself using ingested matter.
A student is checking a classmate’s model for errors. The classmate’s model shows: food entering an organism; the food breaking into smaller molecules; then an arrow labeled “digestion” pointing to an empty space with the label “molecules destroyed.”
Which claim about digestion is incorrect, based on the model idea that digestion breaks down and rearranges food molecules and the evidence needed in a before-and-after comparison?
A model should show what happens before and after digestion to provide evidence of change.
Digestion breaks food into smaller molecules inside the organism.
Digestion destroys the food molecules so they no longer exist as matter inside the organism.
Digestion rearranges smaller molecules into different molecules that can become part of the organism.
Explanation
The core skill in modeling food breakdown is checking models for errors and identifying incorrect claims about digestion. Digestion breaks food into smaller molecules, using enzymes to disassemble food structures. Crucially, these molecules are rearranged, not destroyed, to form new substances within the organism. Models should show before-and-after comparisons to provide evidence of this non-destructive change. A misconception is that digestion eliminates molecules entirely, but proper models reveal their persistence. Breaking down food prepares materials for cellular rearrangement and use. In essence, this process makes food's matter functional for the organism's ongoing needs.
A student says: “When food is digested, it is destroyed, so it no longer exists as matter.” Another student points to a model that shows food entering an organism, being broken into smaller molecules, and then those smaller molecules being rearranged into new molecules that become part of the organism.
Which statement about food breakdown is supported by the model as evidence against the first student’s claim?
Reminder: digestion breaks down and rearranges food molecules.
Digestion changes food into energy only, so molecules are not part of the outcome.
Digestion only happens during chewing, so once food is swallowed it stays the same molecules.
Digestion breaks food molecules into smaller molecules and rearranges them into different molecules, so the matter is changed but not destroyed.
Digestion destroys matter, which is why the organism must keep eating to replace lost matter.
Explanation
The core skill in modeling food breakdown is using models as evidence to counter incorrect claims about digestion destroying matter. Digestion breaks food into smaller molecules, chemically dismantling large food structures within the body. However, these molecules are rearranged into new ones, not destroyed, maintaining the total matter. Models convey this by illustrating food's transformation from entry to integration, with clear before-and-after visuals. A misconception is that digested food ceases to exist, but evidence shows it's repurposed. Breaking down food allows cells to access and reorganize materials for essential functions. This process generalizes that digestion converts food into cellular building blocks, sustaining life.
A student made a simplified before-and-after model of digestion:
Before: A large food molecule enters an organism.
After: The model shows many smaller molecules inside the organism, and later shows those same smaller molecules rearranged into a new molecule labeled “part of the organism.”
Which statement about food breakdown is supported by the evidence in this model?
Reminder: digestion breaks down and rearranges food molecules.
Food molecules stay unchanged; the model only shows them spread out in different places.
Food molecules are rearranged into new molecules that can become part of the organism after they are broken into smaller molecules.
Food becomes smaller only because it is chewed, so the inside of the organism does not change molecules.
The model proves the organism creates new matter during digestion because there are more molecules after than before.
Explanation
The core skill in modeling food breakdown is interpreting simplified before-and-after models to support statements about molecular changes. Digestion breaks food into smaller molecules, simplifying complex foods into basic units through bodily processes. These units are rearranged into new molecules that become part of the organism, conserving matter rather than destroying it. Models represent this by showing large molecules transforming into smaller ones that are reorganized. A misconception is that digestion creates new matter, but models demonstrate it's just reconfiguration. Breaking down food makes its components available for cellular use. This underscores how digestion allows organisms to incorporate external materials into their bodies.
Two students argue about what counts as digestion in a model.
Student 1: “Digestion is just chewing, because the food is broken into smaller pieces.”
Student 2: “Digestion breaks down food molecules into smaller molecules and rearranges them into new molecules.”
A model shows: Food enters → smaller molecules form inside the organism → some smaller molecules are rearranged into new molecules.
Which statement is supported by evidence in the model?
Neither student is correct because digestion destroys matter, so there should be fewer molecules after digestion.
Student 1 is correct because breaking into smaller pieces always means molecules are unchanged.
Student 1 is correct because digestion happens only in the mouth and not inside the organism.
Student 2 is correct because the model shows food molecules broken down into smaller molecules and then rearranged.
Explanation
The core skill is determining which student's view aligns with model evidence of digestion and food breakdown. Digestion breaks food into smaller molecules beyond just physical chewing, involving chemical changes. The smaller units are rearranged into new molecules, conserving matter throughout. Models illustrate this by showing internal molecular changes and recombinations. A misconception is equating digestion solely to chewing, but it includes molecular rearrangement. Breaking down food provides cells with versatile components for synthesis. This process makes food materials usable by cells for sustaining energy and structure.