Name: central dogma: dna to protein
Uploaded: 2025-05-22T09:05:54.000Z
Duration: 1 min 20 s
Channel: JoVE

K12 Standards

Georgia Standards of Excellence

9-12

Biology

SB2.a

The Central Dogma

分子生物学的中心法则指出，DNA 中编码的信息被传递给 RNA，然后 RNA 根据这些指令指导蛋白质的合成。
首先，在转录过程中，DNA 作为模板用于合成信使 RNA 或 mRNA。
mRNA 代表 DNA 编码链的一个拷贝，只是其中的胸腺嘧啶被尿嘧啶所取代。
接下来，核糖体将 mRNA 翻译成一条氨基酸链。
在此，信使RNA（mRNA）上由三个核苷酸组成的密码子与转运RNA（tRNA）分子上的互补序列即反密码子相结合。
每种tRNA根据特定的密码子与相应的氨基酸结合。
例如，密码子 CCA 与连接有脯氨酸的 tRNA 结合，而 AGC 则与连接有丝氨酸的 tRNA 结合。
通过这种方式，遗传密码决定了所生成多肽中氨基酸的排列顺序，该多肽随后经过进一步加工成为具有功能的蛋白质。

中心法则

中心法则解释了遗传信息从 DNA 核苷酸到蛋白质氨基酸序列之间的流动过程。

RNA 是 DNA 和蛋白质之间缺失的一环

1900 年初，科学家发现 DNA 中存储了细胞功能所需的全部信息，而蛋白质则执行了其中的大部分功能。然而，多年以来，将遗传信息转化为功能蛋白的机制仍然是未知的。最初，人们认为单个基因能够直接将其转化为其中已经编码的蛋白质。真核细胞中的两个重要发现对这一理论提出了挑战。首先，蛋白质并不是在细胞核内产生的。其次，DNA 不存在于细胞核之外。这些发现引发了人们寻找一种通过连接 DNA 和蛋白质所生成的中间分子。最终人们发现了这个中间分子便是 RNA。

RNA 是以 DNA 为模板在细胞核中进行合成的。新合成的 RNA 序列与 DNA 链中的序列是相似的，只是胸腺嘧啶会被尿嘧啶所取代。在真核生物中，这种初级转录会被进行进一步加工，同时去除蛋白质非编码区，并对 5' 的末端加帽，添加 3' 末端多聚 A 尾，从而形成成熟的 mRNA，然后再将其输出到细胞质中。

遗传密码是冗余的

真核生物中的蛋白质由 20 种氨基酸所组成的。将四个核苷酸以三个为一组进行组合，能够产生 64 (43) 个密码子。这意味着可以有多个密码子来对单个氨基酸进行编码。因此，遗传密码被称为是冗余的或退化的。一般情况下，指定相同氨基酸的密码子仅在三联体的第三个核苷酸上存在差异。例如，密码子 GUU、GUC、GUA 和 GUG 都能够用来表示氨基酸中的缬氨酸。然而，AUG 是唯一能够代表氨基酸中蛋氨酸的密码子。密码子 AUG 也是蛋白质开始合成时的密码子，因此可以将其称为起始密码子。系统中的冗余能够将突变所产生的有害影响降至最低。例如，密码子中第三个位置的改变不一定能够改变编码的氨基酸，因此这并不会导致蛋白质的功能发生变化。

遗传密码是通用的

除了个别的例外情况，大多数原核生物和真核生物都能够使用相同的遗传密码来合成蛋白质。遗传密码的通用性促进了在农业和医学领域中的科学研究所取得的进步。例如，现在可以利用 DNA 重组技术在细菌中大规模的制造人胰岛素。DNA 重组技术涉及到使用来自不同物种的遗传物质。编码的人胰岛素基因能够与细菌的 DNA 进行结合，并将其插入到细菌细胞中。然后，细菌细胞进行转录和翻译，并产生人胰岛素蛋白，从而使其能够治疗患者的糖尿病。

中心法则解释了遗传信息从DNA核苷酸流向蛋白质氨基酸序列的过程。  
RNA是连接……的缺失环节

Education

教育

JoVE Core

Anatomy and Physiology

解剖学与生理学

Unit 1

第 1 单元

Essential Cellular Processes

细胞基本过程

KEY TERMS AND CONCEPTS

关键术语与概念

中心教条（The Central Dogma）

central dogma: dna to protein

The central dogma explains how genetic information flows in cells from DNA to RNA to protein. It is a core idea in molecular biology and helps show how genes influence cell function.

DNA stores the instructions. During transcription, a cell copies a gene into RNA, which is a related nucleic acid. That RNA message can then be used in translation to build a protein.

Proteins carry out many jobs in cells and help determine traits. The central dogma links the genetic code in DNA to the molecules that do most of the work in living systems.

Central Dogma: DNA to Protein

the central dogma

The central dogma explains how genetic information flows in cells from DNA to RNA to protein. It is a core idea in molecular biology and helps show how genes influence cell function. DNA stores the instructions. During transcription, a cell copies a gene into RNA, which is a related nucleic acid. That RNA message can then be used in translation to build a protein. Proteins carry out many jobs in cells and help determine traits. The central dogma links the genetic code in DNA to the molecules...

replication in eukaryotes

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types of rna

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transcription

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interphase

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the cell cycle control system

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The cell cycle is controlled by checkpoints that help a cell move from one phase to the next and begin mitosis. This control system uses internal regulatory molecules and outside signals to send stop or advance instructions. It makes sure each step is finished before the cell moves forward. Cyclins and cyclin-dependent kinases, or Cdks, are the main regulators of the cell cycle. They act during the G1, G2, and M phases. These regulators work at specific checkpoints to keep cell division...

molecular factors affecting cell division

molecular-factors-affecting-cell-division

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what is meiosis?

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Meiosis is the cell division process that forms gametes, or sex cells. It reduces the chromosome number so offspring can inherit the correct amount of genetic material. This process includes two successive divisions. First, one cell divides, and then the resulting cells divide again. These steps separate the genetic material in a controlled way. Meiosis helps explain how sexual reproduction passes traits from one generation to the next. It is a key topic in high school biology because it...

overview of cell signaling

Cell Signaling Pathways and Responses

Cell signaling pathways and responses help cells communicate and react to changes. Cells send signals to one another, and those signals can trigger a specific response in the target cell. A signal usually begins when a signaling molecule reaches a cell with the right receptor, which is a protein that receives the message. The receptor helps the cell recognize the signal and start the communication process. Inside the cell, the message can move through a signaling pathway. This pathway passes...

types of signaling molecules

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Chemical messengers help cells communicate during signaling. These signaling molecules carry information from one cell to another and guide how cells respond. Some signaling molecules are gases, while others are proteins or peptides. Small lipids can also act as signals. In addition, cells may use steroids, amino acids, and even ions as signaling molecules. Each type of signaling molecule has different properties and works in a different way. Together, these molecules let cells send specific...

g protein-coupled receptors

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G protein-coupled receptors are a major class of cell-surface receptors. They help cells detect signals outside the cell and pass that information inward. These receptors are important in many kinds of cell communication. When a signal binds to a G protein-coupled receptor, the receptor changes shape. That change activates a G protein inside the cell. The activated G protein can then start a signaling pathway. This signaling system includes the receptor, the G protein, and the downstream...

cellular differentiation

From Stem Cell to Specialized Cells

Cellular differentiation turns unspecialized cells into specialized cells with specific jobs. This process helps a complex organism, such as a human, develop from a single fertilized egg into a body with many cell types. Nerve cells, muscle cells, and epithelial cells are examples of the final cell types that appear during development. A zygote is the first cell after fertilization. It is a totipotent stem cell, which means it has very high differentiation potential and can form all cell types...

key terms and concepts

Explore the central dogma and how genetic information moves from DNA to RNA to protein. Learn how transcription and translation connect genes to proteins.

Central Dogma: DNA to Protein | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Replication in Eukaryotes

Types of RNA

Transcription

Translation

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SB2.b

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SB2.c

Obtain, evaluate, and communicate information to analyze how genetic information is expressed in cells

Central Dogma: DNA to Protein

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