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

El ácido desoxirribonucleico, o ADN, consta de dos cadenas de polinucleótidos.
Cada una de estas cadenas está formada por cuatro tipos de subunidades de nucleótidos.
Cada nucleótido consta de un solo grupo fosfato y una base que contiene nitrógeno: adenina, A, citosina, C, guanina, G o timina, T, unida a un azúcar desoxirribosa.
Esta disposición crea la columna vertebral de azúcar-fosfato de la estructura del ADN.
A lo largo de la columna vertebral de cada hebra, los enlaces fosfodiéster unen covalentemente el tercer átomo de carbono de un azúcar con el quinto átomo de carbono de la siguiente molécula de azúcar en la cadena.
En las hebras antiparalelas opuestas, cada base está emparejada de forma única, C con G y A con T, debido a las diferencias en el número de enlaces de hidrógeno que se forman entre ellas.
Tal polaridad química garantiza un empaquetamiento eficiente, enrollando las dos hebras una alrededor de la otra para formar una doble hélice 3-D, con diez pares de bases cada vuelta completa.

la hélice del adn

El ácido desoxirribonucleico, o ADN, es el material genético responsable de transmitir rasgos de generación en generación en todos los organismos y en la mayoría de los virus. El ADN está compuesto por dos hebras de nucleótidos que se enrollan entre sí para formar una estructura similar a un resorte llamada doble hélice. Sin embargo, la doble hélice no es perfectamente simétrica. En cambio, en la estructura aparecen surcos que aparecen regularmente. El surco principal se produce donde las cadenas principales de azúcar y fosfato están relativamente separadas. Este espacio otorga acceso a proteínas de unión al ADN, como los factores de transcripción. El surco menor, por el contrario, se produce donde las cadenas principales de azúcar y fosfato están muy juntas. Relativamente pocas proteínas se unen al ADN a través del surco menor.

El descubrimiento de la estructura del ADN: una breve historia

El descubrimiento de la estructura del ADN se produjo de forma gradual a lo largo de casi un siglo, lo que representa una de las historias más famosas y cautivadoras de la historia de la ciencia.

Todo comenzó en 1869 cuando el científico suizo Friedrich Miescher descubrió una sustancia a la que llamó "nucleína". En el proceso de extracción de proteínas de los glóbulos blancos, Miescher encontró una sustancia inesperada que tenía un contenido de fósforo relativamente alto. No sabía qué era, pero sospechaba que podía tener importancia biológica. Miescher tenía razón, pero la comunidad científica tardó décadas en apreciar plenamente sus ideas.

El siguiente descubrimiento fundamental lo realizó el bioquímico ruso Phoebus Levene. En 1919, Levene propuso que la nucleína, entonces conocida como ácido nucleico, estaba compuesta de cadenas de moléculas a las que llamó polinucleótidos. La propuesta de Levene surgió de su investigación sobre la levadura, en la que descubrió que los nucleótidos individuales estaban compuestos por un grupo fosfato, un azúcar y una base que contenía nitrógeno. Aunque el modelo de polinucleótidos de Levene era correcto en muchos aspectos, aún no estaba claro cómo estaban dispuestas las bases en la molécula de ADN.

El bioquímico austriaco Erwin Chargaff amplió el trabajo de Levene. Trabajando a finales de la década de 1940, Chargaff hizo un hallazgo clave: la cantidad de adenina en el ADN siempre es aproximadamente igual a la cantidad de timina, y la cantidad de guanina siempre es aproximadamente igual a la cantidad de citosina. Este patrón se conoció como la regla de Chargaff y fue una prueba clave que permitió la elucidación final de la estructura del ADN.

A principios de la década de 1950, el biólogo estadounidense James Watson y el físico inglés Francis Crick competían con su principal rival, el estadounidense Linus Pauling, para descubrir la estructura tridimensional del ADN. Basándose en el trabajo de Chargaff, utilizaron conocimientos de física, matemáticas y química para construir modelos físicos de ADN. Pero no tuvieron éxito hasta que recibieron un dato crítico: una "fotografía" de rayos X del ADN que indicaba con detalle preciso su estructura de doble hélice. Esta fotografía era información inédita de la física Rosalind Franklin y fue entregada a Watson y Crick sin el conocimiento de Franklin. Watson y Crick publicaron su descripción de la estructura del ADN en 1953 y, junto con Maurice Wilkins (un colaborador de Franklin), ganaron el Premio Nobel de Fisiología o Medicina en 1962 por este descubrimiento. Lamentablemente, Franklin murió en 1958 y, por lo tanto, no era elegible para el Premio Nobel.

La hélice del ADN

El ácido desoxirribonucleico, o ADN, es el material genético responsable de transmitir rasgos de generación en generación en todos los organismos y en la mayoría de los virus. ADN...

Education

Educación

JoVE Core

Cell Biology

Biología Celular

Unit 1

Unidad 1

Cells, Genomes, and Evolution

Células, genomas y evolución

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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

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the dna helix

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types-of-genetic-transfer-between-organisms

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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

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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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How DNA Structure Was Discovered

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