Gene control · 基因控制
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| lac operon/læk ˈɒpərən/ | 乳糖操纵子 | rǔ táng cāo zòng zi |
| structural gene/ˈstrʌktʃərəl dʒiːn/ | 结构基因 | jié gòu jī yīn |
| regulatory gene/ˌreɡjʊˈleɪtəri dʒiːn/ | 调节基因 | tiáo jié jī yīn |
| inducible enzyme/ɪnˈdjuːsɪbl ˈenzaɪm/ | 可诱导酶 | kě yòu dǎo méi |
| repressor/rɪˈpresə/ | 阻遏物 | zǔ è wù |
| transcription factor/trænˈskrɪpʃn ˈfæktə/ | 转录因子 | zhuǎn lù yīn zi |
| gene expression/dʒiːn ekˈspreʃn/ | 基因表达 | jī yīn biǎo dá |
Switching genes on and off
- Not all genes are switched on all the time.
- Cells control which proteins they make, and when.
- A famous bacterial example is the lac operon 乳糖操纵子.
把基因开和关
- 不是所有基因都一直开着。
- 细胞 控制 它们制造哪些蛋白质,以及何时。
- 一个著名的细菌例子是 乳糖操纵子(lac operon)。
Types of gene and enzyme
- structural genes 结构基因 code for useful proteins such as enzymes.
- regulatory genes 调节基因 control whether other genes are switched on.
- an inducible enzyme 可诱导酶 is made only when needed; a repressible enzyme is normally made but can be switched off.
基因和酶的类型
- 结构基因(structural genes) 编码有用的蛋白质,例如酶。
- 调节基因(regulatory genes) 控制其他基因是否开启。
- 一个 诱导酶(inducible enzyme) 只在需要时制造;一个 阻遏酶(repressible enzyme) 通常制造但能被关闭。
A regulatory gene: · 一个调节基因:
Structural genes code for proteins like enzymes; regulatory genes control whether other genes are switched on. · 结构基因编码像酶这样的蛋白质;调节基因控制其他基因是否开启。
An enzyme that is made only when it is needed (like the lac enzymes) is described as ______. · 一个只在需要时制造的酶(像乳糖酶)被描述为 ______ 的。
Inducible enzymes are produced only when required, which avoids wasting resources. · 诱导酶只在需要时产生,这避免浪费资源。
The lac operon
- In a bacterium, the lac operon controls the digestion of lactose:
- no lactose: a repressor 阻遏物 protein binds the operon and blocks transcription — no enzymes made.
- lactose present: lactose binds the repressor and pulls it off, so transcription happens and the enzymes are made.
- These enzymes are therefore inducible.
The lac operon switches its genes on only when lactose is present
乳糖操纵子
- 在一个细菌中,乳糖操纵子 控制 乳糖(lactose) 的消化:
- 没有乳糖:一个 阻遏物(repressor) 蛋白结合操纵子并 阻断转录——不制造酶。
- 有乳糖:乳糖结合阻遏物并 把它拉掉,所以转录发生,酶被制造。
- 因此这些酶是 诱导的。
乳糖操纵子只在有乳糖时才开启它的基因
The lac operon · 乳糖操纵子
Step through the switch. With no lactose the genes are blocked; lactose pulls the repressor off and switches them on. · 一步步走过这个开关。没有乳糖时基因被阻断;乳糖把阻遏物拉掉并开启它们。
In the lac operon, when there is NO lactose: · 在乳糖操纵子中,当没有乳糖时:
Without lactose, the repressor sits on the operator and blocks transcription of the lac genes. · 没有乳糖,阻遏物坐在操纵基因上并阻断乳糖基因的转录。
When lactose IS present in the lac operon: · 当乳糖操纵子中有乳糖时:
Lactose removes the repressor, allowing transcription — so the lac enzymes are inducible. · 乳糖移除阻遏物,允许转录——所以乳糖酶是诱导的。
Put the lac operon switching ON in order. · 把乳糖操纵子的开启按顺序排列。
Lactose acts as the signal: it removes the repressor, so the genes are only on when their enzymes are needed. · 乳糖充当信号:它移除阻遏物,所以基因只在需要它们的酶时才开启。
In the lac operon, lactose switches the genes ON by removing the repressor from the operator. · 在乳糖操纵子中,乳糖通过把阻遏物从操纵基因移除来开启基因。
Lactose binds and distorts the repressor so it lets go — transcription can then proceed. · 乳糖结合并扭曲阻遏物,所以它松开——然后转录能进行。
Control in eukaryotes
- Transcription factors 转录因子 are proteins that bind DNA and control gene expression 基因表达 (raising or lowering transcription).
- Gibberellin works this way: it causes the breakdown of DELLA repressors, which normally block the factors that switch genes on.
真核生物中的控制
- 转录因子(transcription factors) 是结合 DNA 并控制 基因表达(gene expression)(提高或降低转录)的蛋白质。
- 赤霉素 这样工作:它引起 DELLA 阻遏物的分解,这些阻遏物通常阻断开启基因的因子。
In eukaryotes, transcription factors: · 在真核生物中,转录因子:
Transcription factors bind DNA to raise or lower transcription; gibberellin acts by removing DELLA repressors. · 转录因子结合 DNA 以提高或降低转录;赤霉素通过移除 DELLA 阻遏物起作用。
You've got it
- structural genes (proteins/enzymes) vs regulatory genes (control); inducible (made when needed) vs repressible (switched off)
- lac operon: no lactose → repressor blocks transcription; lactose → pulls repressor off → enzymes made (inducible)
- in eukaryotes, transcription factors control gene expression; gibberellin removes DELLA repressors
你掌握了
- 结构基因(蛋白质/酶)对 调节基因(控制);诱导的(需要时制造)对 阻遏的(被关闭)
- 乳糖操纵子:没有乳糖 → 阻遏物 阻断转录;有乳糖 → 把阻遏物拉掉 → 制造酶(诱导的)
- 在真核生物中,转录因子 控制基因表达;赤霉素 移除 DELLA 阻遏物