This attaches methyl groups (a carbon atom and three hydrogens) to either adenine or cytosine, two of the four chemical bases that form the alphabet of DNA, depending on the gene involved.

该作用可以让甲（由一碳原子和三氢原子组成）附着于腺嘌或胞嘧啶上——组成DNA序列四种主化学成分中两种，到底附着是哪种取决于涉及到种类。

Nucleotides of DNA are made out of a sugar deoxyribose, a phosphate, and one of the four nuclear bases: adenine, cytosine, guanine, and thymine or A, C, G, T for short.

DNA核苷酸由脱氧核糖、磷酸以及四核碱之一组成，分别是腺嘌、胞嘧啶、鸟嘌腺嘧啶，或简称A、C、G、T。

It was known that DNA had four chemical components - called adenine, guanine, cytosine, and thiamine - and that these paired up in particular ways.

当时已经知道，DNA含有4种化学成分——腺嘌、鸟嘌、胞嘧啶和腺嘧啶——这4种成分总是以特殊配对方式排列。

SIRT1 depends on a molecule called NAD (Nicotinamide adenine dinucleotide), and NAD, in turn, depends on the substance called NMN.

SIRT1合成取决于一种叫NAD（辅酶）分子，而NAD合成则取决于一种叫NMN物质。

But for the remaining .1%, one person might have an adenine where another person has a guanine.

但对于剩下0.1%，一人可能有腺嘌而另一人有鸟嘌。

The bases - the letters of the genetic alphabet - consist of the four nucleotides mentioned a page or two back: adenine, thiamine, guanine, and cytosine.

碱——子母表中字母——由前面我们提到腺嘌、鸟嘌、胞嘧吟和腺嘧啶4种核苷酸组成。

Guanine always pairs with cytosine and adenine always pairs with thymine.

鸟嘌总是胞嘧啶配对，腺嘌总是腺嘧啶配对。

NAD, short for nicotinamide adenine dinucleotide, is a coenzyme that occurs naturally in human cells.

NAD， 即烟酰胺腺嘌二核苷酸缩写，是一种天然存在于人体细胞中辅酶。

See, DNA is made up of four different building blocks called " bases" : adenine, cytosine, guanine, and thymine.

看，DNA 由四种称为“碱”不同构件组成：腺嘌、胞嘧啶、鸟嘌和腺嘧啶。

If you look at DNA the bases that we have are cytosine, guanine, adenine and thymine.

如果你看脱氧核糖核酸，我们有碱是胞嘧啶、鸟嘌、腺嘌和腺嘧啶。

These are the letters of RNA or the letters of DNA. Cytosine, guanine, adenine and uracil in RNA.

这些是核糖核酸（RNA）或脱氧核糖核酸（DNA）字母。在RNA中，它们分别是胞嘧啶、鸟嘌、腺嘌和尿嘧啶。

So you've got cytosine, guanine, adenine and uracil.

所以你有胞嘧啶、鸟嘌、腺嘌和尿嘧啶。

Cytosine, guanine, adenine and thymine in DNA. The other difference here is in DNA. We actually have a double helix so those attach together.

在脱氧核糖核酸（DNA）中，含有胞嘧啶、鸟嘌、腺嘌和腺嘧啶。这里一不同之处在于DNA，我们实际上拥有是双螺旋结构，此这些碱对会相互配对连接。

And so in RNA, it's adenine, guanine, uracil and cytosine.

在核糖核酸中，它们是腺嘌、鸟嘌、尿嘧啶和胞嘧啶。

And the reason it's called a TATA Box is you have a thiamine adenine thiamine adenine and on the other side you'd have TATA backwards complimentary to that.

它被称为TATA框原是，你有一段序列包含腺嘧啶（T）、腺嘌（A）、腺嘧啶（T）、腺嘌（A），而在另一侧，你会看到这段序列互补反向序列，即TATA反向互补序列。