Name: how dna structure was discovered
Uploaded: 2023-04-30T10:29:48.000Z
Duration: 1 min 7 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms- Structures and Processes

LS.Bio.1.5

The DNA Helix

Дезоксирибонуклеиновая кислота, или ДНК, состоит из двух полинуклеотидных цепей.
Каждая из этих цепей состоит из четырех типов нуклеотидных субъединиц.
Каждый нуклеотид состоит из одной фосфатной группы и азотсодержащего основания — аденина, А, цитозина, С, гуанина, G или тимина, Т, присоединенного к сахарному дезоксирибозе.
Такое расположение создает сахаро-фосфатную основу структуры ДНК.
Вдоль задней части каждой цепи фосфодиэфирные связи ковалентно связывают третий атом углерода одного сахара с пятым атомом углерода следующей молекулы сахара в цепи.
В противоположных антипараллельных цепях каждое основание уникально спарено, C с G и A с T, из-за разницы в количестве водородных связей, которые образуются между ними.
Такая химическая полярность обеспечивает эффективную упаковку, наматывая две нити друг на друга, образуя трехмерную двойную спираль с десятью парами оснований на каждом полном обороте.

Спираль ДНК

Дезоксирибонуклеиновая кислота, или ДНК, представляет собой генетический материал, ответственный за передачу признаков из поколения в поколение во всех организмах и большинстве вирусов. ДНК состоит из двух нитей нуклеотидов, которые обвиваются друг вокруг друга, образуя пружиноподобную структуру, называемую двойной спиралью. Однако двойная спираль не является совершенно симметричной. Вместо этого в структуре регулярно возникают бороздки. Основная бороздка возникает там, где сахаро-фосфатные остовы расположены относительно далеко друг от друга. Это пространство обеспечивает доступ к ДНК-связывающим белкам, таким как факторы транскрипции. Минорная бороздка, напротив, возникает там, где сахаро-фосфатные цепи расположены близко друг к другу. Относительно небольшое количество белков связывается с ДНК через минорную бороздку. Открытие структуры ДНК: краткая история Открытие структуры ДНК происходило постепенно в течение почти столетия и представляет собой одну из самых известных и захватывающих историй в истории науки. Все началось в 1869 году, когда швейцарский ученый Фридрих Мишер открыл вещество, которое он назвал «нуклеин». В процессе извлечения белка из лейкоцитов Мишер обнаружил неожиданное вещество с относительно высоким содержанием фосфора. Он не знал, что это такое, но подозревал, что это может иметь биологическое значение. Мишер был прав, но научному сообществу потребовались десятилетия, чтобы полностью оценить его идеи. Следующее важное открытие сделал русский биохимик Фебус Левен. В 1919 году Левен предположил, что нуклеин, известный тогда как нуклеиновая кислота, состоит из цепочек молекул, которые он назвал полинуклеотидами. Предложение Левена возникло в результате его исследования дрожжей, в ходе которого он обнаружил, что отдельные нуклеотиды состоят из фосфатной группы, сахара и азотсодержащего основания. Хотя полинуклеотидная модель Левена во многих отношениях была верной, все еще было неясно, как располагаются основания в молекуле ДНК. Австрийский биохимик Эрвин Чаргафф расширил работу Левена. Работая в конце 1940-х годов, Чаргафф сделал ключевое открытие: количество аденина в ДНК всегда примерно равно количеству тимина, а количество гуанина всегда примерно равно количеству цитозина. Эта закономерность стала известна как правило Чаргаффа и стала ключевым доказательством, позволившим окончательно выяснить структуру ДНК. В начале 1950-х годов американский биолог Джеймс Уотсон и английский физик Фрэнсис Крик соревновались со своим главным соперником, американцем Лайнусом Полингом, в открытии трехмерной структуры ДНК. Опираясь на работы Чаргаффа, они использовали знания физики, математики и химии для построения физических моделей ДНК. Но они были безуспешны, пока они не получили критически важные данные: рентгеновскую «фотографию» ДНК, которая в мельчайших подробностях указала на ее двойную спиральную структуру. Эта фотография представляла собой неопубликованные данные физика Розалинда Франклина и была передана Уотсону и Крику без ведома Франклин. Уотсон и Крик опубликовали свое описание структуры ДНК в 1953 году и вместе с Морисом Уилкинсом (коллегой Франклина) получили за это открытие Нобелевскую премию по физиологии и медицине 1962 года. К сожалению, Франклин умер в 1958 году и поэтому не имел права на Нобелевскую премию.

Дезоксирибонуклеиновая кислота, или ДНК, является генетическим материалом, ответственным за передачу признаков из поколения в поколение у всех организмов и большинства вирусов. ДНК...

Education

JoVE Core

Cell Biology

Клеточная биология

Unit 1

Раздел 1

Cells, Genomes, and Evolution

Клетки, геномы и эволюция

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

how dna structure was discovered

DNA is the genetic material that passes traits from one generation to the next in organisms and most viruses. It is made of two strands of nucleotides that twist into a spring-like double helix. The shape is not perfectly even. It also has repeating grooves called the major groove and the minor groove.

The major groove forms where the sugar-phosphate backbones are farther apart. This wider space gives DNA-binding proteins, including transcription factors, better access to the bases. The minor groove forms where the backbones are closer together. Relatively few proteins bind to DNA through the minor groove.

The story of DNA structure unfolded over nearly a century. It began in 1869, when Swiss scientist Friedrich Miescher found a phosphorus-rich substance in white blood cells and called it nuclein. He did not know what it was, but he suspected it had biological importance. Later work showed that his idea was right.

In 1919, Russian biochemist Phoebus Levene proposed that nucleic acid was made of chains of molecules called polynucleotides. His yeast studies showed that each nucleotide contains a phosphate group, a sugar, and a nitrogen-containing base. This model was useful, but it still did not explain how the bases were arranged in DNA. In the late 1940s, Erwin Chargaff added a key clue by showing that adenine is roughly equal to thymine and guanine is roughly equal to cytosine.

That evidence helped James Watson and Francis Crick build their DNA models in the early 1950s. They were competing with Linus Pauling and used ideas from physics, mathematics, and chemistry. They succeeded only after seeing an X-ray photograph of DNA that showed the double helix in detail. The image came from Rosalind Franklin’s unpublished data and was shared without her knowledge. Watson and Crick published their description in 1953, and with Maurice Wilkins they received the 1962 Nobel Prize in Physiology or Medicine. Franklin died in 1958, so she was not eligible for the prize.

How DNA Structure Was Discovered

what are cells?

Cells as the Building Blocks of Life

Cells are the basic building blocks of life. A bacterium can be a single cell, while a human is made of trillions of cells. Even with this range, cells share key features that support life. A living cell has a plasma membrane. This is a bilayer of lipids that separates the cytoplasm inside the cell from the outside environment. A cell also carries genetic information in the form of DNA. In prokaryotic cells, DNA is found in a region called the nucleoid. In eukaryotic cells, DNA is enclosed...

the tree of life - bacteria, archaea, and eukaryotes

the-tree-of-life-bacteria-archaea-and-eukaryotes

Three Domains on the Tree of Life

The tree of life shows how living things are grouped into three domains: Bacteria, Archaea, and Eukaryotes. This classification helps explain the major branches of life and how they are related. Bacteria and Archaea are both single-celled organisms, but they are not the same. Eukaryotes include organisms with more complex cells, such as plants, animals, and fungi. Together, these three domains give a broad picture of life on Earth. Understanding the tree of life helps students compare cell...

prokaryotic cells

How Prokaryotes Survive Without a Nucleus

Prokaryotes are small unicellular organisms that live without a nucleus. They include the domains Archaea and Bacteria. Bacteria include common microbes such as Salmonella and E. coli, while Archaea include extremophiles that live in harsh places like volcanic springs. Prokaryotic cells still share several basic features with eukaryotic cells. They have a plasma membrane, cytoplasm, ribosomes, and genetic material in the form of single, circular DNA. Their cell parts float freely in the...

eukaryotic compartmentalization

How Organelles Keep Cells Working

Eukaryotic cells keep their organelles separate so each part can do a specific job. Organelles such as the nucleus and mitochondria are surrounded by membranes. These membranes are selectively permeable, which means they control what enters and leaves. That control creates small internal environments with conditions suited to each organelle. These controlled spaces help organelles work more efficiently. In animal cells, lysosomes keep an acidic environment that helps their enzymes digest...

eukaryotic evolution

How Eukaryotic Cells Became Complex

Eukaryotic cells became complex through a debated evolutionary path that likely involved endosymbiosis. The most accepted model is the endosymbiont theory, which explains how organelles such as mitochondria and chloroplasts may have entered an ancestral cell. Other ideas include the nucleus-first hypothesis, the mitochondria-first hypothesis, and the eukaryote-first hypothesis. The nucleus-first hypothesis says an ancestral prokaryote first formed a membrane around its DNA, creating the...

animal and plant cell structure

Plant vs Animal Cell Division and Specialization

Plant and animal cells differ in how they divide, organize into tissues, and specialize for different jobs. Both cell types divide by mitosis in non-gametic cells and by meiosis in gametic cells, but the details are not the same. These differences help explain how each cell type supports growth and reproduction. During cell division, animal cells use centrosomes to organize spindle fibers and separate chromosomes. Plant cells do not have centrosomes. Instead, they use a microtubule-organizing...

cytoplasm

Cytoplasm and the Cell’s Internal Support

The cytoplasm is the cell’s internal space that holds organelles and the cytoskeleton. It is suspended in the cytosol, an aqueous fluid made of water, ions, salts, and many organic molecules. This fluid helps keep the cell organized and supports many cellular activities. The cytoplasm is also where protein synthesis and protein folding take place. The watery cytosol helps proteins fold correctly. In a folded protein, hydrophobic amino acid side chains tend to stay buried in the core, while...

the nucleus

Nuclear DNA, Chromatin, and Nucleoli

The nucleus is a membrane-bound organelle that stores chromosomal DNA and helps control what proteins a eukaryotic cell makes. It acts as the cell’s control center. DNA in mitochondria and chloroplasts is different because it mainly supports functions specific to those organelles. Inside the nucleus, DNA is wrapped around proteins called histones. This DNA-protein complex is called chromatin. During interphase, when the cell is not dividing, chromatin stays loosely arranged so the DNA is easy...

the dna helix

DNA is the genetic material that passes traits from one generation to the next in organisms and most viruses. It is made of two strands of nucleotides that twist into a spring-like double helix. The shape is not perfectly even. It also has repeating grooves called the major groove and the minor groove. The major groove forms where the sugar-phosphate backbones are farther apart. This wider space gives DNA-binding proteins, including transcription factors, better access to the bases. The minor...

the central dogma

DNA to Protein: RNA’s Role

DNA to protein flow depends on RNA as the link between genetic information and the amino acids that build proteins. Early scientists knew that DNA stores the information for cell functions and that proteins carry out most of those functions. For a long time, they did not know how the code in DNA became a working protein. At first, many people thought one gene was changed directly into its protein. Two findings in eukaryotic cells challenged that idea. Protein production does not happen in the...

mutations

Mutations in DNA and Inherited Disease

Mutations are changes in the DNA sequence. They can happen on their own during DNA copying, or they can be caused by environmental factors. Scientists describe mutations in several ways, including whether they change the amino acid sequence of a protein, how much DNA they affect, and whether they occur in somatic cells or germline cells. Some mutations are point mutations. A point mutation changes a single nucleotide in DNA. Other mutations are chromosomal alterations, which change the number...

genome size and the evolution of new genes

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

Genome Size and Gene Evolution

Genome size and gene evolution are linked through changes in DNA sequence and genome structure. Some genes can arise from parts of the genome that were not coding before, while others come from changes to existing genes. These shifts help explain how new genetic material can appear over time. A genome is the full set of DNA in an organism. Its size can change as DNA is added, removed, or rearranged. The transcript highlights that genome size is not fixed, and that these changes can shape the...

gene families

Shared Origins of Gene Families

Gene families are groups of related genes that share a common origin. They form when genes are copied and then change over time. These related genes can be found within the same genome. The video also connects gene families to homologous genes and orthologous genes. Homologous genes are genes with a shared evolutionary origin. Orthologous genes are homologous genes found in different species. Gene families help show how these relationships are used to study evolution and related gene functions.

gene evolution - fast or slow?

Gene Evolution Rates and Selection

Gene evolution can happen at different rates, and natural selection helps shape those changes. Some genes change slowly because important DNA changes are removed over time. Other genes can change more quickly when different mutations are kept in a population. The rate of evolution depends on how a gene is used and how strongly it is affected by selection. Genes with essential jobs often stay more similar across species. Genes under weaker pressure may show more variation and may evolve faster.<br...

types of genetic transfer between organisms

types-of-genetic-transfer-between-organisms

Vertical and Horizontal Gene Transfer

Genetic transfer between organisms happens in two main ways: vertical gene transfer and horizontal gene transfer. These two routes explain how hereditary material moves from one generation to the next or between organisms that are not parent and offspring. Vertical gene transfer passes genes from parent to offspring during reproduction. This is the usual way genetic information is inherited in living things. Horizontal gene transfer moves genetic material between organisms outside of...

key terms and concepts

Explore how scientists uncovered DNA’s double helix, from Miescher’s nuclein to Chargaff’s rule, Franklin’s X-ray image, and Watson and Crick.

How DNA Structure Was Discovered | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Pennsylvania State Academic Standards

Life Science

Inheritance and Variation of Traits

3.1.9-12.P

3.1.9-12.Q

Louisiana Student Standards for Science

High School

Life Sciences

From Molecules To Organisms: Structures And Processes

HS-LS1-1

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance And Variation Of Traits

HS-LS3-1

Biological Evolution: Unity And Diversity

HS-LS4-1

Tennessee Academic Standards

From Molecules to Organisms: Structures and Processes

BIO1.LS1.3

Virginia  Standards of Learning

HIgh School

BIO.2

BIO.2.d

BIO.5

BIO.5.b

Minnesota Academic Standards in Science

3.1.1 9L.3.1.1.4

Florida Department of Education

SC.912.L.16

SC.912.L.16.4

SC.912.L.18

SC.912.L.18.1

Texas Essential Knowledge and Skills

BIO.7

BIO.7.A

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

B-LS1-1.

Heredity: Inheritance and Variation of Traits

B-LS3-1.

Georgia Standards of Excellence

SB6.c

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Macromolecules

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lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

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Nucleic Acids and Nucleotides

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Nucleic Acid Structure

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ATP Energy Storage and Release

ATP and Macromolecule Synthesis

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Construct an explanation to illustrate relationships between structure and function of major macromolecules essential for life.

LS.Bio.1.1

Introduction to Enzymes

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Enzymes and Activation Energy

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Introduction to Enzyme Kinetics

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Turnover Number and Catalytic Efficiency

The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from ...

Catalytically Perfect Enzymes

The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at ...

introduction-to-mechanisms-of-enzyme-catalysis

Introduction to Mechanisms of Enzyme Catalysis

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Ligand Binding and Linkage

Cooperative Allosteric Transitions

Ribozymes

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LS.Bio.1.2

What are Cells?

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium or trillions of them, ...

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (&#x3BC;m)and are considerably smaller than most ...

Eukaryotic Compartmentalization

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Prokaryotic Cells

Prokaryotes are small unicellular organisms that include the domains&#x2014;Archaea and Bacteria. Bacteria include many common organisms, such as ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

Endoplasmic Reticulum

Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer ...

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are ...

Lysosomes

Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules ...

Peroxisomes

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Introduction to the Cytoskeleton

Overview of the Cytoskeleton
The cytoskeleton is a network of protein filaments present within the cell, having three distinct filaments ...

Use models to explain how the structure of organelles determines its function and supports overall cell processes.

LS.Bio.1.3

Analyze how the relationship between structure and function supports life processes within organisms.

How DNA Structure Was Discovered

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