Mechanisms of Transport · 运输机制
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| pump/pʌmp/ | 泵 | bèng |
| endocytosis/ˌendəʊsɪˈtəʊsɪs/ | 胞吞作用 | bāo tūn zuò yòng |
| vesicle/ˈvesɪkl/ | 囊泡 | náng pào |
| exocytosis/eɡˌzɒsɪˈtəʊsɪs/ | 胞吐作用 | bāo tǔ zuò yòng |
Pumping and hauling
- Sometimes a cell must move a substance the "wrong" way — against its gradient.
- Sometimes the load is far too big for any protein doorway.
- For both jobs, the cell spends energy and uses clever machinery.
- These are the active mechanisms of transport.
泵送与搬运
- 有时细胞必须把一种物质往"错误"的方向移动——逆着它的梯度。
- 有时负载对任何蛋白质门户来说都太大了。
- 对这两项工作,细胞都花费能量并使用巧妙的机械。
- 这些就是主动的运输机制。
Protein pumps
- A pump 泵 is a carrier protein that moves ions against their gradient.
- It spends ATP to change shape and push the ion uphill.
- The sodium-potassium pump keeps nerve and muscle cells ready to fire.
- Without pumps, a cell could never build up ions above its surroundings.
蛋白质泵
- 泵(pump)是逆离子梯度移动离子的载体蛋白。
- 它花费 ATP 来改变形状,把离子往上推。
- 钠钾泵让神经和肌肉细胞随时准备好放电。
- 没有泵,细胞就永远无法把离子积累到高于周围。
A protein pump moves ions against their gradient using… · 一个蛋白质泵逆梯度移动离子,使用……
A pump is active transport: it spends ATP to move ions from low to high concentration. · 泵是主动运输:它花费 ATP 把离子从低浓度移到高浓度。
Endocytosis: taking it in
- For big loads, the cell uses its membrane like a net.
- In endocytosis 胞吞作用 the membrane wraps around material and pinches inward.
- This forms a vesicle 囊泡 — a small bubble — carrying the load inside.
- This is how a cell can swallow something as big as a whole bacterium.
内吞:把它带进来
- 对大的负载,细胞把它的膜当作一张网。
- 在内吞作用(endocytosis)中,膜包住物质并向内收缩。
- 这形成一个囊泡(vesicle)——一个小气泡——把负载运进内部。
- 这就是细胞能吞下像整个细菌那么大的东西的方式。
A protein pump in action · 蛋白质泵在工作
Step the pump through its cycle — it spends ATP to move a particle against the gradient, from low to high. · 让泵走过它的循环——它花费 ATP 把一个粒子逆梯度从低运到高。
In endocytosis, the cell… · 在内吞作用中,细胞……
Endocytosis takes material in by wrapping the membrane around it to form a vesicle. · 内吞作用通过用膜包住物质形成囊泡,把物质带进来。
Exocytosis: sending it out
- The reverse process ships material out of the cell.
- In exocytosis 胞吐作用 a vesicle moves to the membrane and fuses with it.
- Its contents spill to the outside.
- This is how cells release hormones, enzymes, and waste.
胞吐:把它送出去
- 逆过程把物质运出细胞。
- 在胞吐作用(exocytosis)中,一个囊泡移到膜处并与它融合。
- 它的内容物溢到外面。
- 这就是细胞释放激素、酶和废物的方式。
Releasing material by fusing a vesicle with the membrane is called ____. · 通过让囊泡与膜融合来释放物质,叫做 ____。
In exocytosis a vesicle fuses with the membrane and dumps its contents outside. · 在胞吐作用中,一个囊泡与膜融合,把它的内容物倒到外面。
Endocytosis and exocytosis move materials too large to fit through a membrane protein. · 内吞和胞吐移动的物质太大,无法通过膜蛋白。
Bulk transport handles large loads — like whole cells or big molecules — that no channel could pass. · 大宗运输处理大的负载——比如整个细胞或大分子——任何通道都无法通过。
Select all · 所有 true statements about transport mechanisms. · 选出关于运输机制的所有正确说法。
Pumps are active transport and do need ATP. The other three are correct. · 泵是主动运输,确实需要 ATP。其余三条正确。
Pumps, endocytosis, and exocytosis all cost energy. Unlike diffusion, they can move things against a gradient or move loads too big for any channel — but the cell must pay for all of it with ATP.
泵、内吞和胞吐都花费能量。不像扩散,它们能把东西逆梯度移动,或移动对任何通道来说都太大的负载——但细胞必须用 ATP 为这一切付费。
A white blood cell eating a germ:
- The germ is far too big to fit through any membrane protein.
- The white blood cell flows its membrane around the germ (endocytosis).
- The germ is sealed inside a vesicle, then destroyed — how your body fights infection.
一个白细胞吃掉一个病菌:
- 病菌太大了,无法通过任何膜蛋白。
- 白细胞把它的膜流动包住病菌(内吞)。
- 病菌被封在一个囊泡里,然后被摧毁——这就是你身体对抗感染的方式。
Active mechanisms move things diffusion cannot. A pump spends ATP to push ions uphill. Endocytosis wraps the membrane around a large load to bring it in as a vesicle; exocytosis fuses a vesicle with the membrane to release material out. All three cost energy.
主动机制移动扩散无法移动的东西。泵花费 ATP 把离子往上推。内吞用膜包住大负载,把它作为囊泡带进来;胞吐让囊泡与膜融合,把物质释放出去。这三者都花费能量。