Name: dna to protein: central dogma steps
Uploaded: 2020-11-23T11:47:33.000Z
Duration: 1 min 25 s
Channel: JoVE

K12 Standards

Minnesota Academic Standards in Science

9-12

Life Science

1.1.1 9L.1.1.1.1

The Central Dogma

分子生物学的中心法则规定
 
 DNA中编码的信息会转移到RNA上
 
 然后根据这些指示
 
 指导蛋白质的合成
 
 首先 在转录过程中
 
 DNA用作模板以合成信使RNA
 
 mRNA 其代表编码链的拷贝
 
 除了胸腺嘧啶被替换为尿嘧啶
 
 接下来 在真核生物中的
 
 翻译过程中
 
 mRNA移动到核糖体
 
 这里 mRNA中的三个核苷酸的密码子
 
 与转移RNA tRNA分子上的
 
 互补序列结合
 
 根据具体的密码子 每个氨基酸
 
 与特定的氨基酸连接
 
 例如 密码子CCA与附着于脯氨酸的
 
 tRNA结合 而AGC结合附着于
 
 丝氨酸的tRNA
 
 以这种方式 遗传密码规定了
 
 氨基酸在所得多肽中
 
 排列的顺序
 
 然后通常将多肽进一步
 
 加工成为功能性蛋白质

史密斯、安和肯娜·肖。"发现 DNA 与蛋白质生产之间的关系。"自然教育 1 第 1 期（2008）:112。[<a href="https://www.nature.com/scitable/topicpage/discovering-the-relationship-between-dna-and-protein-27699" target="__blank">来源</a>]

拉尔斯顿、艾米和肯娜·肖。"阅读遗传密码。"自然教育 1 第 1 期 （2008）:120。[<a href="https://www.nature.com/scitable/topicpage/reading-the-genetic-code-1042" target="__blank">来源</a>]

中心法则

”生物学的中心法则是，DNA中编码的信息被传递给信使RNA (mRNA)，然后信使RNA指导蛋白质的合成。使mRNA核苷酸序列解码成氨基酸的一组指令称为遗传密码。这种遗传密码的普遍性刺激了科学研究、农业和医学的进步。”

<h4>RNA是DNA和蛋白质之间缺失的连接</h4>
 
在20世纪初，科学家们发现，DNA储存了细胞功能所需的所有信息，而蛋白质履行了这些功能的大部分。然而，将遗传信息转化为功能蛋白的机制多年来一直是未知的。最初，人们认为单个基因直接转化为其编码的蛋白质。在真核细胞中的两个重要发现挑战了这一理论：第一，蛋白质的产生并不发生在细胞核中。其次，DNA不存在于细胞核外。这些发现引发了对一种将DNA与蛋白质生产联系起来的中间分子的研究。这种中间分子存在于细胞核和细胞质中，与蛋白质的产生有关，就是RNA。
 
在转录过程中，RNA在细胞核中合成，以DNA为模板。新合成的RNA在序列上与DNA链相似，只是DNA中的胸腺嘧啶被RNA中的尿嘧啶所取代。在真核生物中，这一原始转录本被进一步处理，去除蛋白质的非编码区，盖上5端并添加一个3多聚-a尾，以产生mRNA，然后输出到细胞质中。
 
<h4>解释mRNA序列的规则构成了遗传密码</h4>
 
翻译发生在细胞质中的核糖体上，在那里，mRNA中编码的信息被翻译成氨基酸链。一组由三个核苷酸组成的氨基酸编码，这三个核苷酸被称为密码子。密码子一套规则，概括了哪些密码子指定了构成遗传密码的特定氨基酸。
 
<h4>遗传密码是多余的</h4>
 
蛋白质是由真核生物中的20种氨基酸产生的。将四个核苷酸以三个为一组组合起来提供64个 ( 43 ) 可能的密码子。这意味着单个氨基酸可能由多个密码子编码。遗传密码被认为是多余的或退化的。通常，但并不总是，指定相同氨基酸的密码子只在三联体的第三个核苷酸中不同。例如，密码子 GUU, GUC, GUA 和 GUG都代表氨基酸缬氨酸。然而， AUG是唯一代表氨基酸蛋氨酸的密码子。密码子AUG也是蛋白质合成的起始密码子，因此被称为起始密码子。系统中的冗余将突变的有害影响最小化。密码子第三位的突变（即改变）不一定导致氨基酸的改变。
 
<h4>遗传密码是通用的</h4>
 
除了少数例外，大多数原核生物和真核生物使用相同的基因编码合成蛋白质。这种遗传密码的普遍性使得科学研究、农业和医学的发展成为可能。例如，人类胰岛素现在可以在细菌中大规模生产。这是用重组DNA技术完成的。重组DNA由不同物种的遗传物质组成。编码人胰岛素的基因与细菌DNA结合并插入细菌细胞中。细菌细胞进行转录和翻译，产生编码在重组DNA中的人胰岛素。由此产生的人胰岛素用于治疗糖尿病。

概述

生物学的中心法则指出，DNA 中编码的遗传信息会传递给信使 RNA（mRNA），随后由 mRNA 指导蛋白质的合成……

Education

教育

JoVE Core

Molecular Biology

分子生物学

Unit 1

第一单元

DNA, Cells, and Evolution

DNA、细胞与进化

KEY TERMS AND CONCEPTS

关键术语与概念

中心教条（The Central Dogma）

dna to protein: central dogma steps

The central dogma explains how genetic information moves from DNA to RNA to protein. This flow is a key idea in molecular biology. It helps show how cells use genes to make the molecules that carry out work.

DNA stores the instructions for making proteins. During transcription, a gene in DNA is copied into RNA. The RNA then carries that message to the next stage.

In translation, the RNA message is used to build a protein. Proteins do much of the cell’s work, so this process connects genes to traits and cell function. Understanding the central dogma helps students see how information in DNA becomes an active product in the cell.

DNA to Protein: Central Dogma Steps

the dna helix

DNA Structure and Base Pairing

DNA has a helical structure that helps store genetic information. The double helix is the shape formed by two strands that twist around each other. This structure is a key feature of DNA in cells. The two strands are held together by base pairing. Bases on one strand match with bases on the other strand in a regular way. This pairing helps keep the DNA molecule stable and organized. The helix shape also helps explain how DNA fits into chromosomes and carries instructions for living things. By...

the central dogma

The central dogma explains how genetic information moves from DNA to RNA to protein. This flow is a key idea in molecular biology. It helps show how cells use genes to make the molecules that carry out work. DNA stores the instructions for making proteins. During transcription, a gene in DNA is copied into RNA. The RNA then carries that message to the next stage. In translation, the RNA message is used to build a protein. Proteins do much of the cell’s work, so this process connects genes to...

prokaryotic cells

Inside Prokaryotic Cell Structure

Prokaryotic cells have a simple internal structure compared with many other cells. They are usually divided into two groups: bacteria and archaea. These cells have no nucleus, so their DNA is not enclosed in a membrane-bound compartment. Instead, the genetic material is found in the nucleoid, a region where the DNA is located in the cell. Some prokaryotic cells also contain plasmids, which are small extra DNA molecules. A capsule may surround the cell and provide an additional outer layer. <br...

eukaryotic compartmentalization

Cell Compartments in Eukaryotes

Eukaryotic cells use compartments to organize many different jobs inside one cell. These compartments help separate processes so they can happen in the right place. The compartment called the cytosol is the fluid part of the cell. It surrounds the other internal structures and helps support many cell processes. Inside the cell, membrane-bound organelles create distinct microenvironments. A microenvironment is a small internal space with conditions that fit a specific task. This separation...

the tree of life - bacteria, archaea, eukaryotes

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How Life Is Classified Into Three Domains

The tree of life shows how organisms are related through evolution. Its root represents the common ancestor of all life on Earth. From that point, branches spread out like a tree. The tips of the branches represent living, or extant, species. Species that no longer exist, called extinct species, appear closer to the center of the tree. Today, these organisms are grouped into three domains: bacteria, archaea, and eukaryotes. Scientists still debate these divisions, so the tree of life keeps...

mutations

How Mutations Change DNA

Mutations are changes in DNA. They can alter the genetic code and affect how genes work. In high school biology, students often study mutations to understand how DNA changes can influence traits. The transcript focuses on two common mutation types: point mutations and frameshift mutations. A point mutation changes one nucleotide, which is one DNA building block. A frameshift mutation happens when nucleotides are added or removed and the reading frame shifts. These changes matter because they...

gene evolution - fast or slow?

Why Some Gene Regions Evolve Faster

Gene regions do not all change at the same rate. In eukaryotes, long stretches of DNA do not code for proteins or RNAs. Some of these non-coding regions include important regulatory sequences, but most have no known function. Because little or no selection pressure acts on them, they often change the fastest over evolutionary time. Protein-coding regions usually evolve more slowly. A change in a coding sequence can alter a protein and make it less effective at doing its job. That creates...

genome size and the evolution of new genes

genome-size-and-the-evolution-of-new-genes

How Genome Size Shapes New Genes

Genome size can vary widely, and it also helps show how new genes form. Every living organism has a genome, whether it uses RNA or DNA. Yet the size of that genome can be very different from one organism to another. One major difference is whether the organism is prokaryotic or eukaryotic. Prokaryotic genomes usually have little to no non-coding sequence, which means genes are packed closely together in operons along the chromosome. Eukaryotic genomes contain long stretches of non-coding DNA...

gene families

How Gene Families Evolve and Diversify

Gene families are groups of genes that are thought to come from a shared ancestor. They usually form when a gene is copied by mistake during cell division. The original gene stays under selection pressure to keep its job, while the extra copy can change more quickly over time. Some copied genes gain a new role in the organism. When that happens, they are called paralogs, which are two genes in the same species that evolved from one common ancestral gene. Gene families also include orthologs,...

types of genetic transfer between organisms

types-of-genetic-transfer-between-organisms

How Genes Move Within and Across Generations

Genetic transfer is the movement of genetic information from one organism to another. It happens in two main ways: vertical gene transfer and horizontal gene transfer. Vertical gene transfer moves genes from one generation to the next. It is much more common than horizontal gene transfer. Vertical gene transfer happens during both sexual reproduction and asexual reproduction. In both cases, one or more organisms pass some or all of their genome to their offspring. This kind of transfer occurs...

key terms and concepts

Learn how genetic information moves from DNA to RNA to protein through transcription and translation, and how this process helps cells make proteins.

DNA to Protein: Central Dogma Steps | JoVE K12

molecular biology

JoVE Core 分子生物学通过清晰简洁的动画视频课程展示了细胞的分子过程。此外，在科学家在行动的视频中，这些概念的应用是通过现代实验室中的真实实验演示的。

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

High School

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS3-1

Next Generation Science Standards

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From Molecules to Organisms: Structures and Processes

HS-LS1-1

new-york-state-science-learning-standards

New York State Science Learning Standards

Structure and Function

HS-LS1-1.

myJoVE Corporation

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Heterochromatin

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1 Exploring phenomena or engineering problems
 1.1 Asking questions and defining problems
  1.1.1 Students will be able to ask questions about aspects of the phenomena they observe, the conclusions they draw from their models or scientific investigations, each other’s ideas, and the information they read.

DNA to Protein: Central Dogma Steps

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