Membrane Transport · 膜运输
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| passive transport/ˈpæsɪv ˈtrænspɔːt/ | 被动运输 | bèi dòng yùn shū |
| active transport/ˈæktɪv ˈtrænspɔːt/ | 主动运输 | zhǔ dòng yùn shū |
Two ways across the membrane
- A cell must move materials in and out all day long.
- Some movement is free; some has to be paid for with energy.
- The direction of travel decides which one is needed.
- Sorting transport into these two kinds makes it all click.
穿过膜的两种方式
- 细胞必须整天把物质运进运出。
- 有些移动是免费的;有些必须用能量来支付。
- 移动的方向决定需要哪一种。
- 把运输分成这两类,一切就都说得通了。
Passive transport: free
- Passive transport 被动运输 moves substances down their concentration gradient.
- It uses no energy — the particles' own motion does the work.
- Simple diffusion, facilitated diffusion, and osmosis are all passive.
- Movement continues until the gradient disappears.
被动运输:免费
- 被动运输(passive transport)把物质沿它们的浓度梯度向下移动。
- 它不用能量——粒子自己的运动做了工作。
- 简单扩散、易化扩散和渗透都是被动的。
- 移动持续到梯度消失为止。
Passive transport moves substances… · 被动运输把物质……
Passive transport goes down the concentration gradient and costs the cell no energy. · 被动运输沿浓度梯度向下,不花费细胞能量。
Active transport: pay with ATP
- Active transport 主动运输 moves substances against their gradient — from low to high.
- Going uphill needs energy, supplied by ATP.
- A carrier protein acts as a pump, using that energy.
- This lets a cell build up a substance far above its surroundings.
主动运输:用 ATP 支付
- 主动运输(active transport)把物质逆它们的梯度移动——从低到高。
- 往上走需要能量,由 ATP 提供。
- 一个载体蛋白充当泵,使用那份能量。
- 这让细胞能把一种物质积累到远高于周围的水平。
What makes active transport different from passive transport? · 主动运输与被动运输有什么不同?
Active transport spends ATP to pump substances against their gradient, from low to high. · 主动运输花费 ATP 把物质逆它们的梯度泵送,从低到高。
Active transport requires energy from ATP. · 主动运输需要来自 ATP 的能量。
Moving substances uphill against a gradient needs energy — supplied by ATP. · 把物质逆梯度往上移动需要能量——由 ATP 提供。
Comparing the two
- Passive goes with the gradient; active goes against it.
- Passive is free; active costs ATP.
- Both can use proteins, but only active spends energy.
- The direction of travel is the quickest way to tell them apart.
比较两者
- 被动顺着梯度;主动逆着梯度。
- 被动免费;主动花费 ATP。
- 两者都可以用蛋白质,但只有主动花费能量。
- 移动的方向是区分它们最快的办法。
Passive or active? · 被动还是主动?
Sort each kind of transport by whether it needs energy and which way it moves. · 按照每种运输是否需要能量、往哪个方向移动,给它们分类。
The passive movement of water across a membrane has a special name: . · 水跨膜的被动移动有一个特别的名字:。
Osmosis · 渗透 is the passive diffusion of water across a selectively permeable membrane. · 渗透是水跨过选择透过性膜的被动扩散。
Select all · 所有 true statements about membrane transport. · 选出关于膜运输的所有正确说法。
Passive transport needs no energy, so not all · 所有 transport does. The other three are correct. · 被动运输不需要能量,所以并非所有运输都需要。其余三条正确。
The tell-tale is direction, not speed. If a substance is moving against its gradient (low to high), it must be active transport using ATP — nothing moves uphill for free. Down the gradient is passive.
关键的标志是方向,不是速度。如果一种物质正在逆它的梯度移动(从低到高),它一定是用 ATP 的主动运输——没有东西能免费往上走。顺着梯度向下的是被动。
Root cells pumping in minerals:
- Soil often has a lower mineral concentration than the root cell inside.
- Yet the plant still needs to take minerals in — uphill.
- Root cells use active transport, spending ATP to pump minerals against the gradient.
根细胞泵入矿物质:
- 土壤里的矿物质浓度常常比里面的根细胞更低。
- 然而植物仍然需要吸收矿物质——往上走。
- 根细胞使用主动运输,花费 ATP 把矿物质逆梯度泵入。
Membrane transport is either passive or active. Passive transport moves substances down the gradient with no ATP (diffusion, facilitated diffusion, osmosis). Active transport uses ATP to pump substances against the gradient. The direction of travel — with or against the gradient — tells you which.
膜运输要么是被动的,要么是主动的。被动运输沿梯度向下移动物质,不用 ATP(扩散、易化扩散、渗透)。主动运输用 ATP 把物质逆梯度泵送。移动的方向——顺着还是逆着梯度——告诉你是哪一种。