Now, in the blood, each red blood cell has millions of hemoglobin proteins.

在血液中，个血细胞都有数百万的血。

And each of those hemoglobins can bind to four oxygen molecules.

而一个血能与4个氧分子结合。

They are made in the bone marrow and contain a special ion-containing protein called hemoglobin.

它们是在骨髓中形成的，含有一种叫做血的特殊含离子质。

These disorders are caused by genetic mutations that prevent the normal production of hemoglobin.

这些疾病是由阻止血正常产生的因突变引起的。

So each hemoglobin can carry four oxygen molecules when it's fully saturated.

所以在饱和时，一个血可以携带四个氧分子。

The illnesses are caused by errors in the gene for hemoglobin.

这些疾病是由血因缺陷引起的。

But the fact is, hemoglobin's affinity for oxygen isn't always the same.

但事实是，血对氧气的亲和力并不总是一样的。

Normally, hemoglobin is made up of four globin chains, each bound to a heme group.

正常情况下，血由4条珠链组成，条珠链都与一个血素团结合。

They also have a special type of hemoglobin, the molecule in the blood that transports oxygen.

他们同时有着一种特殊的血，这种分子在血液中负责运输氧气。

Carbon monoxide and oxygen compete to bite hemoglobin in your blood, which stresses the circulatory system.

一氧化碳和氧气争先恐后地与血液中的血结合，这给血液循环系统带来了压力。

Now your hemoglobin is known as oxyhemoglobin, or HbO2.

现在你的血被称为氧合血，或 HbO2。

These four globin chains combine in different ways to give rise to different kinds of hemoglobin.

这四种珠链以不同的方式结合，形成不同类型的血。

If there are three defective alpha genes, there's moderate disease, called hemoglobin H, or HbH, disease.

如果有3个α因异常，则出现中度地中海贫血，即血H病（HbH病）。

It says that an increase in carbon dioxide results in hemoglobin proteins releasing oxygen into the tissues.

当血液中的二氧化碳增多时，血会把细胞绑定的氧气释放到人体组织中去。

Their hemoglobin is much stickier for oxygen than ours and can pick oxygen up even when it's scarce.

它们的血比我们的更加粘，能够在氧气很稀薄的情况下也能进行收集。

When red blood cells do not have enough hemoglobin, oxygen doesn't get to all parts of the body.

当细胞没有足够的血时，氧气就无法到达身体的各个部位。

To treat sickle cell disease, researchers used CRISPR to make the body produce the fetal form of hemoglobin.

为了治疗镰状细胞病，研究人员使用 CRISPR 使身体产生胎儿形式的血。

The modified cells are then infused back into the body to allow it to start producing functioning hemoglobin.

然后将修改后的细胞注入体内，使其开始产生功能正常的血。

But, for example, if I looked at, fetal hemoglobin relinquishes that oxygen at lower oxygen tensions.

但是，举个例子，如果我看到，胎儿血在较低的氧张力下放弃氧气。

One of the adaptations that the body makes after it's been at high altitude is to make more hemoglobin.

在高海拔地区，身体的其中一个适应就是制造更多的血。