A strong blow to the head causes chemical changes within nerve cells that damage their structural proteins.

头部遭受的猛烈撞击会使得神经细胞发生化学变化，成结构蛋白损伤。

The exchange of materials occurs between cells and their environment across the cell membrane.

物质交换穿过细胞膜发生在细胞与其环境之间。

Telepathy goes on within the body between the cells.

心灵感应在身体内的细胞之间发生。

Aerobic respiration happens all the time in all cells, usually in the mitochondria.

有氧呼吸每时每刻都在细胞中发生，通常在线粒体中。

They also found changes in the mix of cells within the animals' immune system itself.

同时他发现，在动物免疫系统自身，混合细胞有发生改变。

Cell division is an intricate chemical dance that's part individual, part community-driven.

细胞分裂，是繁复的化学舞蹈，一部分在细胞内发生，一部受外界影响。

What if a cancer cell mutates and finds  a way to circumvent this process?

如果癌细胞发生突变并找到绕过这一过程的方法怎么办？

They went up the first space missions to see what would happen to human cells and zero gravity.

他执一次太空任务，看看在失重情况下人体细胞会发生什么。

So, what happens when different cells get hit?

那么，不同细胞被攻击时会发生什么呢？

Now, a tumor develops if there's a DNA mutation in any of these cell types that leads to uncontrolled cell division.

如果以上提到的这些细胞发生DNA突变，成细胞分裂失控，就会发展为肿瘤。

Researchers found that the earliest mutations of cancer are displayed on every cell in a tumor.

研究人员发现，肿瘤的每个细胞都会发生癌症的最初变异。

In fact, that's exactly what happens during apoptosis, also known as programmed cell death.

事实上，这恰恰是细胞凋亡时所发生的现象，这一过程也被称作细胞程序性死亡。

Finally, a tumor cell changes in a way  that makes it properly dangerous, cancer.

最后，肿瘤细胞发生变化，使其变得非常危险，即癌症。

If it hijacks the immune system, and a cytokine storm occurs?

如果被它操控整个免疫系统 并且发生细胞因子风暴？

This is possible because organisms evolve when random mutations happen in the DNA of reproductive cells.

这是可能的，因为当生殖细胞的DNA发生随机突变时，生物就会化。

For example, the light that enters your eye causes chemical changes in cells at the back of the eye.

例如，入眼睛的光线会导致眼睛后部的细胞发生化学变化。

Well, sometimes cancer cells mutate more  and get much better at fighting back.

嗯，有时癌细胞会发生更多突变，并且更善于反击。

That's what leads to permanent mutations in your DNA, and down the line, possibly cancerous cells.

这就是导致您的 DNA 发生永久性突变的原因， 并可能导致癌细胞发生永久性突变。

What's going on here at the cellular level?

在细胞水平上发生什么？

Once a cancer-causing mutation occurs within a cell, the affected cell begins to grow and replicate out of control, forming a tumor.

一旦细胞发生致癌的基因突变，受累细胞会不受控地生长复制，形成肿瘤。