运输
国际文凭组织 · IB Diploma · 生物 · HL 知识点 16 3:52 英语旁白 · 英中内嵌字幕
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文本转录
Two foods can have the same mass but provide different nutrients.
两种食物可能具有相同的质量，但提供的营养素不同。
A health claim must distinguish the nutrient measured from the health outcome inferred.
健康声明必须区分所测量的营养素与推断出的健康结果。
Large insoluble food molecules are digested into smaller soluble molecules.
大型不溶性食物分子被消化成较小的可溶性分子。
Carbohydrases form sugars, proteases form amino acids, and lipases form fatty acids and glycerol.
淀粉酶生成糖类，蛋白酶生成氨基酸，脂肪酶生成脂肪酸和甘油。
Bile emulsifies lipids and helps neutralize acidic stomach contents.
胆汁乳化脂质并帮助中和酸性胃内容物。
Digestion is the breakdown of large food molecules.
消化是指大型食物分子的分解过程。
Absorption is the movement of soluble products into the body.
吸收是指可溶性产物进入体内的过程。
Absorption moves soluble products into blood or lymph.
吸收将可溶性产物运入血液或淋巴。
Thin exchange surfaces and a large surface area shorten diffusion paths and increase transfer.
薄的交换表面和大的表面积缩短了扩散路径并增加了转运量。
Enzyme activity and transport are different processes.
酶活性与运输是不同的过程。
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.
在实验室中，使用本尼迪特试剂并配合受控加热来检测还原糖。 使用碘液检测淀粉。 使用双缩脲试剂检测蛋白质。 使用乙醇乳化法检测脂质。 远离火源保存乙醇。 使用阳性对照和阴性对照。
Known: six of 24 study participants report a condition.
已知：24名研究参与者中有6人报告出现某种状况。
Proportion equals cases divided by total.
比例等于病例数除以总数。
Percentage equals 6 over 24, times 100, which is 25 percent.
百分比为6/24乘以100，即25%。
The percentage describes this sample.
该百分比描述的是此样本。
It does not establish that one food caused the condition; confounders and how the sample was chosen matter.
它并不能确立是某种食物导致了该状况；混杂因素以及样本的选择方式都很重要。
Your turn: 9 of 36 participants report an outcome.
请作答。 36 名参与者中有 9 人报告了结果。
Calculate the percentage.
请计算百分比。
Pause the video and work it out.
请暂停视频，自己算一算。
Check: 9 divided by 36 is 25 percent.
核对：9 ÷ 36 = 25%。
Bile is not an enzyme.
胆汁不是酶。
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.
阳性食物检测结果仅表明在特定测试条件下存在某种成分，并不能说明该食物在所有饮食中都是健康或不健康的。
Not true: A correlation between diet and illness proves causation.
不正确：饮食与疾病之间的相关性证明因果关系。
A correlation shows that two measurements vary together; it does not prove one causes the other.
相关性仅表明两个测量值共同变化，并不能证明一方导致另一方。
A confounding variable, reverse causation or chance could explain the link, so a controlled comparison is needed before claiming causation.
混杂变量、反向因果或偶然因素都可能解释这种关联，因此在声称因果关系之前，需要进行对照比较。
Large insoluble food molecules are digested into smaller soluble molecules.
大型不溶性食物分子被消化成较小的可溶性分子。
Absorption moves soluble products into blood or lymph.
吸收将可溶性产物转运至血液或淋巴中。
Watch for: bile is not an enzyme.
请注意：胆汁不是酶。
Six out of forty participants report an outcome.
40名参与者中有6人报告了结果。
Find the percentage.
计算百分比。
The sample percentage is not proof that one food caused it.
样本百分比并不能证明某种食物导致了该结果。
The result is 15 percent of a sample.
结果是样本的15%。
Large food molecules cannot cross the gut wall.
大分子食物不能穿过肠壁。
Enzymes digest them into small soluble products, which are then absorbed into blood or lymph.
酶把它们消化成小的可溶性产物，再被吸收进入血液或淋巴。
Fictional surveys record an outcome in 9 of 36 and 12 of 60 participants.
虚构的调查显示，36 名参与者中有 9 人、60 名参与者中有 12 人出现了某种结果。
Compare percentages. Give two reasons why this cannot establish that a food caused the outcome.
请比较这两个百分比，并给出两个理由，说明为什么这不能证明该食物导致了这一结果。
The percentages are 25 percent and 20 percent.
两个百分比分别是 25% 和 20%。
Confounding and selection or reporting bias can explain differences; temporal ordering and comparable measurement also matter.
混杂因素以及选择偏倚或报告偏倚都可能解释差异；时间先后顺序和测量是否可比也很重要。
This is evidence evaluation, not dietary advice.
这是对证据的评估，而不是饮食建议。
Pause and check yourself. Explain each point on screen in your own words, then change one number in the last example and say which assumption must still hold.
暂停一下，自我检查：用自己的话解释屏幕上的每个要点，再改动最后一个例子中的一个数字，说明哪个假设仍然必须成立。