Digestion, transport and health evidence
הוצג| English | משמעות |
|---|---|
| digestion/daɪˈdʒestʃn/ | הערכה |
| absorption/əbˈsɔːpʃn/ | ספיגה |
What would explain this observation?
- Two foods can have the same mass but provide different nutrients. A health claim must distinguish the nutrient measured from the health outcome inferred.
Build the model
- Large insoluble food molecules are digested into smaller soluble molecules.
- Carbohydrases form sugars, proteases form amino acids, and lipases form fatty acids and glycerol.
- Bile emulsifies lipids and helps neutralize acidic stomach contents.
- digestion 消化: Breakdown of large food molecules.
- absorption 吸收: Movement of soluble products into the body.
Which statement about bile is correct?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Bile is made in the liver and emulsifies lipids: it breaks large fat droplets into smaller ones, increasing the surface area for lipase. Bile is not an enzyme, so it is not a protease, and it digests nothing itself, so it cannot break nutrients into monomers.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Absorption moves soluble products into blood or lymph.
- Thin exchange surfaces and a large surface area shorten diffusion paths and increase transfer.
- Enzyme activity and transport are different processes.
In the lab: Use Benedict reagent with controlled heating for reducing sugars, iodine for starch, Biuret reagent for protein, and the ethanol emulsion test for lipids. Keep ethanol away from flames. Use positive and negative controls.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: 6 of 24 study participants report a condition.
- Proportion = cases / total.
- Percentage = 6/24 × 100 = 25%.
- The percentage describes this sample.
- It does not establish that one food caused the condition; confounders and how the sample was chosen matter.
Your turn: 9 of 36 participants report an outcome. Calculate the percentage.
9 of 36 participants report an outcome. Calculate the percentage.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 25 %. Known: 9 of 36 participants report the outcome. Use percentage = cases / total x 100. Percentage = 9/36 x 100 = 25%. This describes the sample only; it does not show that a food caused the outcome.
Check the conclusion and its limits
- Bile is not an enzyme.
- A positive food test identifies a component under the test conditions; it does not show that a food is healthy or unhealthy in every diet.
Not true: A correlation between diet and illness proves causation. A correlation shows that two measurements vary together; it does not prove one causes the other. A confounding variable, reverse causation or chance could explain the link, so a controlled comparison is needed before claiming causation.
- Large insoluble food molecules are digested into smaller soluble molecules.
- Absorption moves soluble products into blood or lymph.
- Watch for: bile is not an enzyme.
Write from 20 percent of a sample
- 4 of 20 study participants report a condition.
- Find the percentage. The percentage does not prove that one food caused the condition.
A correlation shows that two measurements vary together; it does not prove one causes the other.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
True. A correlation shows that two measurements vary together; it does not prove one causes the other. A confounding variable, reverse causation or chance could explain the link, so a controlled comparison is needed before claiming causation.
Breakdown of large food molecules: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
digestion means Breakdown of large food molecules.
4 of 20 study participants report a condition. What percentage is that, and what does the percentage not prove?
Percentage is the count divided by the sample size. Correlation is not causation.
What percentage of this sample reported the condition?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
4 divided by 20 is 20 percent. The worked example's 6 of 24 is a different sample. Other options — 4 percent (the case count); 25 percent (the worked sample's percentage).