Origins of Cell Compartmentalization · 细胞区室化的起源
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| endosymbiosis/ˌendəʊˌsɪmbaɪˈəʊsɪs/ | 内共生 | nèi gòng shēng |
| endosymbiotic theory/ˌendəʊˌsɪmbaɪˈɒtɪk ˈθɪəri/ | 内共生学说 | nèi gòng shēng xué shuō |
Where did the rooms come from?
- Eukaryotic cells are full of membrane-bound organelles.
- But the first cells were simple, like today's bacteria.
- So how did the complex, compartmented cell arise?
- The answer is one of biology's most surprising stories.
这些房间从哪来?
- 真核细胞充满了膜包被的细胞器。
- 但最早的细胞很简单,像今天的细菌。
- 那么复杂的、有区室的细胞是怎么出现的?
- 答案是生物学最令人惊讶的故事之一。
Folding the membrane inward
- Some organelles came from the cell's own membrane folding inward.
- These infoldings pinched off to form the nucleus and endomembrane system.
- This built compartments from a structure the cell already had.
- But two organelles have a stranger origin.
把膜向内折叠
- 有些细胞器来自细胞自己膜的向内折叠。
- 这些内陷收缩脱离,形成细胞核和内膜系统。
- 这用细胞已有的结构构建了区室。
- 但有两个细胞器的起源更奇怪。
The nucleus and ER are thought to have formed from… · 细胞核和内质网被认为形成自……
The nucleus and endomembrane system likely arose by the plasma membrane folding inward. · 细胞核和内膜系统很可能是由质膜向内折叠而产生的。
Endosymbiosis: a cell within a cell
- Endosymbiosis 内共生 is one cell living permanently inside another.
- Long ago, a large cell engulfed a small bacterium but did not digest it.
- The bacterium made ATP; the host sheltered it — a partnership.
- Over generations, that bacterium became the mitochondrion.
内共生:细胞里的细胞
- 内共生(endosymbiosis)是一个细胞永久地生活在另一个细胞内部。
- 很久以前,一个大细胞吞噬了一个小细菌,但没有消化它。
- 细菌制造 ATP;宿主庇护它——一种合作。
- 经过许多代,那个细菌变成了线粒体。
The endosymbiotic theory · 内共生学说
Step through how a free-living bacterium became a permanent organelle inside a larger cell. · 一步步走过一个自由生活的细菌如何变成一个更大细胞内部的永久细胞器。
The endosymbiotic theory explains the origin of… · 内共生学说解释了……的起源。
Endosymbiosis proposes that mitochondria and chloroplasts were once free-living bacteria engulfed by a host cell. · 内共生提出线粒体和叶绿体曾经是被宿主细胞吞噬的自由生活的细菌。
The evidence
- Mitochondria and chloroplasts keep their own small, circular DNA.
- They are wrapped in a double membrane, a clue to being engulfed.
- They divide on their own, just like bacteria.
- This is why the endosymbiotic theory 内共生学说 is widely accepted.
证据
- 线粒体和叶绿体保留着它们自己的小的、环状的 DNA。
- 它们被一层双层膜包裹,这是被吞噬的一条线索。
- 它们自己分裂,就像细菌一样。
- 这就是内共生学说(endosymbiotic theory)被广泛接受的原因。
Which observation supports endosymbiosis? · 哪个观察支持内共生?
Mitochondria keep their own circular DNA, a double membrane, and divide on their own — just like bacteria. · 线粒体保留它们自己的环状 DNA、一层双层膜,并自己分裂——就像细菌一样。
Mitochondria and chloroplasts contain their own DNA. · 线粒体和叶绿体含有它们自己的 DNA。
They keep a small circular genome, a leftover from their free-living bacterial past. · 它们保留一个小的环状基因组,这是它们自由生活的细菌过去留下的痕迹。
Select all · 所有 true statements about the origin of organelles. · 选出关于细胞器起源的所有正确说法。
Only mitochondria and chloroplasts were engulfed bacteria — not every organelle. The other three are correct. · 只有线粒体和叶绿体是被吞噬的细菌——不是每个细胞器。其余三条正确。
Only mitochondria and chloroplasts came from engulfed bacteria. Do not say every organelle was once a bacterium — the nucleus, ER, and Golgi formed by membrane infolding, not endosymbiosis.
只有线粒体和叶绿体来自被吞噬的细菌。不要说每个细胞器曾经都是细菌——细胞核、内质网和高尔基体是由膜内陷形成的,不是内共生。
A fingerprint from the past:
- Your mitochondria carry a tiny loop of DNA, separate from the DNA in your nucleus.
- That mitochondrial DNA looks bacterial, not like your own.
- It is a molecular fossil of the free-living bacterium your ancestors' cells once swallowed.
来自过去的一枚指纹:
- 你的线粒体携带一小圈 DNA,与你细胞核里的 DNA 分开。
- 那份线粒体 DNA 看起来像细菌的,不像你自己的。
- 它是一块分子化石,记录着你祖先的细胞曾经吞下的那个自由生活的细菌。
Eukaryotic compartments arose two ways. The nucleus and endomembrane system formed by the membrane folding inward. Mitochondria and chloroplasts arose by endosymbiosis — engulfed bacteria that became organelles — supported by their own DNA, double membranes, and self-division (the endosymbiotic theory).
真核区室以两种方式产生。细胞核和内膜系统由膜向内折叠形成。线粒体和叶绿体由内共生产生——被吞噬的细菌变成了细胞器——由它们自己的 DNA、双层膜和自我分裂支持(内共生学说)。