Lipids · 脂质
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| lipid/ˈlɪpɪd/ | 脂质 | zhī zhì |
| fatty acid/ˈfæti ˈæsɪd/ | 脂肪酸 | zhī fáng suān |
| saturated/ˈsætʃəreɪtɪd/ | 饱和的 | bǎo hé de |
| unsaturated/ʌnˈsætʃəreɪtɪd/ | 不饱和的 | bù bǎo hé de |
| phospholipid/ˈfɒsfəlɪpɪd/ | 磷脂 | lín zhī |
| hydrophobic/ˌhaɪdrəˈfəʊbɪk/ | 疏水的 | shū shuǐ de |
The water-fearing family
- Lipids are the fats, oils, and waxes of the cell.
- They store more energy per gram than any other food molecule.
- They also build every cell membrane and act as insulation.
- What unites them is simple: they do not mix with water.
怕水的家族
- 脂质是细胞里的脂肪、油和蜡。
- 它们每克储存的能量比任何别的食物分子都多。
- 它们还构建每一张细胞膜,并起到隔热的作用。
- 让它们成为一家的道理很简单:它们不与水混合。
Triglycerides: energy stores
- A lipid 脂质 called a triglyceride stores energy in fat.
- It is one glycerol molecule joined to three fatty acid 脂肪酸 tails.
- Long fatty-acid tails pack a lot of energy into a small space.
- This is why animals store spare energy as fat, not sugar.
甘油三酯:能量储存
- 一种叫甘油三酯的脂质(lipid)把能量储存在脂肪里。
- 它是一个甘油分子连着三个脂肪酸(fatty acid)尾巴。
- 长长的脂肪酸尾巴把大量能量装进很小的空间。
- 这就是动物把多余能量储存为脂肪而不是糖的原因。
A triglyceride is made of one glycerol joined to… · 甘油三酯由一个甘油连上……组成。
A triglyceride is a glycerol backbone with three fatty acid tails attached. · 甘油三酯是一个甘油骨架,连着三个脂肪酸尾巴。
Saturated vs unsaturated
- A saturated 饱和的 fatty acid has no double bonds — straight chains that pack tightly (a solid fat).
- An unsaturated 不饱和的 fatty acid has C=C double bonds that kink the chain (a liquid oil).
- More double bonds means a more liquid, lower-melting lipid.
- Animal fats tend to be saturated; plant and fish oils tend to be unsaturated.
饱和与不饱和
- 一个饱和(saturated)脂肪酸没有双键——直直的链紧密堆积(固态脂肪)。
- 一个不饱和(unsaturated)脂肪酸有 C=C 双键使链弯折(液态油)。
- 双键越多,脂质越偏液态、熔点越低。
- 动物脂肪往往是饱和的;植物油和鱼油往往是不饱和的。
What makes a fatty acid unsaturated? · 是什么让一个脂肪酸变成不饱和的?
An unsaturated fatty acid has C=C double bonds, which kink the chain and keep it liquid (an oil). · 不饱和脂肪酸有 C=C 双键,使链弯折并保持液态(油)。
Phospholipids build membranes
- A phospholipid 磷脂 has a phosphate head that likes water and two fatty-acid tails that fear it.
- In water, phospholipids line up into a double layer — a bilayer.
- Heads face the water outside and inside; tails hide in the middle.
- This bilayer is the basis of every cell membrane.
磷脂构建膜
- 一个磷脂(phospholipid)有一个喜欢水的磷酸头和两个怕水的脂肪酸尾。
- 在水中,磷脂排列成双层——一个双分子层。
- 头朝向外面和里面的水;尾巴藏在中间。
- 这个双层是每一张细胞膜的基础。
Sort the lipids · 给脂质分类
Group each lipid by its structure and main job in the body. · 按照结构和在身体里的主要作用,给每种脂质分组。
The lipid that builds cell membranes is the ____. · 构建细胞膜的脂质是 ____。
A phospholipid has a water-loving head and water-fearing tails, so it forms the membrane bilayer. · 磷脂有一个亲水的头和疏水的尾,所以它形成膜的双层。
Select all · 所有 true statements about lipids. · 选出关于脂质的所有正确说法。
Lipids are hydrophobic, so they do not · 不 dissolve in water. The other three are correct. · 脂质是疏水的,所以它们不溶于水。其余三条正确。
Do not treat "fat" as simply bad. Lipids are essential: they store energy, cushion organs, insulate the body, build every membrane, and form steroid hormones. The body cannot work without them.
不要把"脂肪"简单当作坏东西。脂质是必需的:它们储存能量、缓冲器官、隔热、构建每一张膜,并形成类固醇激素。身体没有它们就无法工作。
Lipids are hydrophobic — they do not mix with water. · 脂质是疏水的——它们不与水混合。
Lipids are nonpolar, so water cannot surround them — they are hydrophobic ("water-fearing"). · 脂质是非极性的,所以水无法包围它们——它们是疏水的("怕水的")。
Why oil and water separate:
- Lipid tails are nonpolar, so water molecules cannot hydrogen-bond to them.
- Water pulls together and squeezes the lipids out.
- Being hydrophobic 疏水的 is exactly what lets phospholipids form a stable membrane in a watery cell.
油和水为什么分离:
- 脂质尾巴是非极性的,所以水分子无法与它们形成氢键。
- 水彼此拉在一起,把脂质挤出去。
- 疏水的(hydrophobic)正是让磷脂能在含水的细胞里形成稳定膜的原因。
Lipids are hydrophobic molecules. Triglycerides (glycerol + three fatty acids) are concentrated energy stores; saturated fats are solid, unsaturated oils are liquid. Phospholipids form the membrane bilayer because their tails are hydrophobic and their heads are not.
脂质是疏水的分子。甘油三酯(甘油 + 三个脂肪酸)是浓缩的能量储存;饱和脂肪是固态,不饱和油是液态。磷脂形成膜的双层,因为它们的尾是疏水的、头不是。