Simple plant cells may have only one or two chloroplasts in them.

简单的植物细胞有一个或两个叶。

Finally, let's look at the chloroplast.

最后是叶。

Chloroplasts are found only in plant cells and contain chlorophyll.

叶存在于植物细胞内，而且含有叶素。

Over time, that evolved into a chloroplast, the organelle that does photosynthesis.

随着时间的推移，们进化成叶，也就是进行光合作用的细胞器。

Today, every single plant has cells like this, full of chloroplasts and mitochondria.

今天，每一株植物都有这样的细胞，充满叶和线粒。

Plant cells also contain chloroplasts which are filled with a chemical called chlorophyll.

植物细胞还包含叶，里面充满了一种叫做叶素的化学物质。

It sucks the cell empty and digests most of its contents, but the chloroplasts remain intact.

将细胞吸空，并消耗其大部分物质，留下“叶”完好无损。

This makes the chloroplasts able to sustain themselves for longer inside the slug.

这使得叶够在鼻涕虫内维持更长时间。

You won't find chloroplasts in animals — they're more of a plant thing. You wouldn't understand, Blobfish.

你在动物身上找不到叶——们更像是植物的组成部分。你不会明白的，水滴鱼。

But these first eukaryotic plants were soon consumed by other animals, which hijacked the precious chloroplast, just like Elysia.

但这些最早的真核植物很快就被其他动物吃掉了，并被劫持了珍贵的叶，就像叶海天牛一样。

As incredible as this adaptation is, there are more than 70 species of slug that steal chloroplasts from their food.

如此令人难以置信的适应性，竟然有多达 70 多种鼻涕虫从食物中窃取叶。

And cyanobacteria became chloroplasts, the organelles that carry out photosynthesis today.

蓝藻变成了叶，即今天进行光合作用的细胞器。

Tripos is in turn eaten by other mixotrophic algae, providing frequent opportunity for exchange of organelles such as chloroplasts.

角藻又被其他混合营养藻类吞食，为叶等细胞器的交换提供频繁的机会。

We call this kleptoplasty." Klepto" , as in to steal, " plasty" as in chloroplast, right?

我们称这种 kleptoplasty 为“Klepto”，就像偷窃一样，“plasty”就像在叶中一样，对吧？

Taking a chloroplast and sticking inside of a cellis not enough to become photosynthetic.

获取叶并粘在细胞内部不足以进行光合作用。

And at the end of these branches, we have these cul de sacs that are loaded with chloroplasts.

在这些分支的尽头，我们有这些装有叶的死胡同。

Chloroplasts need things that the algae provide to themthat animals shouldn't be able to do.

叶需要藻类为们提供的动物无法提供的东西。

Some of these tiny plants were not digested and lived on in the animal cells, eventually giving rise to chloroplasts.

这些微小植物并无法消化和吸收这些动物细胞，最终形成了叶。

During this process, sunlight hits structures within a plant's cells called chloroplasts, which are packed with chlorophyll pigments.

在光合作用中，太阳光照射在植物细胞里一些叫做叶的结构上，而这些叶中含有大量的叶素色素。

Each leaf parenchyma cell can hold hundreds of chloroplasts — that's where all the photosynthesis happens and what gives leaves their signature green color.

每个薄壁细胞以容纳数百个叶——这是光合作用发的地方，也是树叶标志性的色的来源。