Name: hydrogen bonding and dna stability
Uploaded: 2025-05-22T09:05:54.000Z
Duration: 1 min 4 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Physical Science

SC.912.P.8

SC.912.P.8.6

Hydrogen Bonds

Eine Wasserstoffbrückenbindung ist eine intermolekulare elektrostatische Anziehungskraft zwischen einem Wasserstoffatom und einem elektronegativen Atom mit einem einsamen Elektronenpaar.
In einem polaren Molekül wie Fluorwasserstoff oder HF, Ammoniak oder NH3 und Wasser oder H2O ist das Fluor-, Stickstoff- oder Sauerstoffatom elektronegativer als Wasserstoff.
Das elektronegativere Atom zieht bindende Elektronenpaare stärker an als Wasserstoff. Dies führt zu einer ungleichen Elektronenverteilung in der Bindung, wodurch das elektronegative Atom teilweise negativ und das Wasserstoffatom teilweise positiv geladen ist.
Die partielle positive Ladung am Wasserstoffatom ermöglicht es ihm, ein nicht gebundenes Elektronenpaar eines elektronegativen Atoms in seiner Nähe anzuziehen und eine Wasserstoffbrückenbindung zu bilden.
Wasserstoffbrückenbindungen verleihen verschiedenen biologischen Molekülen, einschließlich der DNA, strukturelle Stabilität.

wasserstoffbrückenbindungen

Eine Wasserstoffbrückenbindung entsteht, wenn ein schwach positiv geladenes Wasserstoffatom, das bereits an ein elektronegatives Atom gebunden ist (zum Beispiel das Sauerstoffatom im Wassermolekül), von einem weiteren elektronegativen Atom aus einem anderen polaren Molekül, wie Wasser (H2O), Fluorwasserstoff (HF) oder Ammoniak (NH3), angezogen wird. Der große Elektronegativitätsunterschied zwischen dem H-Atom (2,1) und dem Atom, an das es gebunden ist (4,0 für das F-Atom, 3,5 für das O-Atom oder 3,0 für das N-Atom), kombiniert mit der sehr kleinen Größe des H-Atoms, führt zu einer ungleichmäßigen Verteilung der Ladungen zwischen dem Wasserstoffatom und dem elektronegativen Atom. Dadurch wird das Wasserstoffatom teilweise positiv und das elektronegative Atom teilweise negativ. Moleküle mit F-H-, O-H- oder N-H-Einheiten werden daher von ähnlichen Einheiten benachbarter Moleküle stark angezogen und bilden eine besonders starke Dipol-Dipol-Wechselwirkung, die als Wasserstoffbrückenbindung bezeichnet wird. 

Wasserstoffbrückenbindungen haben einen deutlichen Einfluss auf die Eigenschaften von Flüssigkeiten und Feststoffen. Zum Beispiel sind der Schmelzpunkt und der Siedepunkt von Methylamin (CH3NH2) höher als bei Ethan (CH3CH3), obwohl beide ähnlich groß und massiv sind. Im Gegensatz zu Ethan besitzt Methylamin eine −NH-Gruppe, die es ihm ermöglicht, Wasserstoffbrückenbindungen zu bilden und die intermolekularen Kräfte zwischen Molekülen zu erhöhen, wodurch sich schließlich seine Schmelz- und Siedepunkte erhöhen. 

Wasserstoffbrückenbindungen sind in der Natur weit verbreitet, wie zum Beispiel bei der DNA, die genetische Informationen enthält und in jedem Organismus vorkommt. Jedes Basenpaar der DNA entsteht durch Wasserstoffbrückenbindung über drei Wasserstoffbrückenbindungen. Diese komplementäre Basenpaarung trägt zur Form und Stabilität der DNA-Doppelhelixstruktur bei. 

Dieser Text wurde angepasst von <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/">Openstax, Anatomy and Physiology 2e, Section 2.2: Chemical Bonds</a> und <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/">Openstax, Chemistry 2e, Section 10.1: Intermolecular Forces</a>.

Wasserstoffbrückenbindungen

Eine Wasserstoffbrückenbindung entsteht, wenn ein schwach positives Wasserstoffatom bereits an ein elektronegatives Atom gebunden ist (z. B. den Sauerstoff im Wassermolekül) ...

Education

Lehre

JoVE Core

Anatomy and Physiology

Anatomie und Physiologie

Unit 1

Einheit 1

Fundamentals of Chemistry

Grundlagen der Chemie

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

hydrogen bonding and dna stability

Hydrogen bonding helps explain why some molecules stick together more strongly than others. A hydrogen bond forms when a weakly positive hydrogen atom, already bonded to an electronegative atom, is attracted to another electronegative atom on a nearby polar molecule. Common examples include water, hydrogen fluoride, and ammonia.

This attraction happens because hydrogen has a much lower electronegativity than atoms such as fluorine, oxygen, and nitrogen. The electronegativity difference, along with hydrogen’s very small size, creates an uneven charge. The hydrogen becomes partially positive, and the electronegative atom becomes partially negative. Molecules with F-H, O-H, or N-H groups can then form a strong dipole-dipole attraction called a hydrogen bond.

Hydrogen bonding can change the properties of liquids and solids. For example, methylamine has a higher melting point and boiling point than ethane, even though the two molecules are similar in size and mass. The difference is that methylamine has an -NH group, which lets it form hydrogen bonds and strengthens the intermolecular forces between its molecules.

Hydrogen bonds are also important in living things. DNA, which carries genetic information in every organism, relies on hydrogen bonding between base pairs. Each base pair is held together by three hydrogen bonds. This complementary pairing helps give DNA its double helix shape and supports its stability.

Hydrogen Bonding and DNA Stability

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the periodic table and organismal elements

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ionic bonds

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hydrogen bonds

Hydrogen bonding helps explain why some molecules stick together more strongly than others. A hydrogen bond forms when a weakly positive hydrogen atom, already bonded to an electronegative atom, is attracted to another electronegative atom on a nearby polar molecule. Common examples include water, hydrogen fluoride, and ammonia. This attraction happens because hydrogen has a much lower electronegativity than atoms such as fluorine, oxygen, and nitrogen. The electronegativity difference, along...

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key terms and concepts

Learn how hydrogen bonding forms, why it strengthens intermolecular forces, and how it helps raise boiling points and stabilize DNA.

Hydrogen Bonding and DNA Stability | 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.

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

States of Matter

Solids, liquids, and gases are the three states of matter commonly found on Earth. A solid is rigid and possesses a definite shape. A liquid flows and ...

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Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Differentiate between physical and chemical properties and physical and chemical changes of matter.

SC.912.P.8.1

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

Phase Transitions

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Clausius-Clapeyron Equation

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Phase Transitions: Melting and Freezing

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phase-transitions-sublimation-and-deposition

Phase Transitions: Sublimation and Deposition

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Heating and Cooling Curves

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Phase Diagrams

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SC.912.P.8.2

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

The Wave Nature of Light

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The Electromagnetic Spectrum

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Interference and Diffraction

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Photoelectric Effect

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The Bohr Model

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Emission Spectra

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The de Broglie Wavelength

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The Uncertainty Principle

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The Quantum-Mechanical Model of an Atom

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Explore the scientific theory of atoms (also known as atomic theory) by describing changes in the atomic model over time and why those changes were necessitated by experimental evidence.

SC.912.P.8.3

Elements: Chemical Symbols and Isotopes

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Ions and Ionic Charges

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The Periodic Table

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Atomic Mass

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Atomic Number and Mass Number

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Explore the scientific theory of atoms (also known as atomic theory) by describing the structure of atoms in terms of protons, neutrons and electrons, and differentiate among these particles in terms of their mass, electrical charges and locations within the atom.

SC.912.P.8.4

Periodic Classification of the Elements

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Electron Configurations

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Electronic Structure of Atoms


An atom comprises protons and neutrons, which are contained inside the dense, central&#160;core called the nucleus, with electrons present around the ...

Electron Behavior

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atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Atomic Orbitals

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The Pauli Exclusion Principle

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The Energies of Atomic Orbitals

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The Aufbau Principle and Hund's Rule

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electron-configuration-of-multielectron-atoms

Electron Configuration of Multielectron Atoms

The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the ...

Relate properties of atoms and their position in the periodic table to the arrangement of their electrons.

SC.912.P.8.5

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

Covalent Bonding and Lewis Structures

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Bonding in Metals

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Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

Distinguish between bonding forces holding compounds together and other attractive forces, including hydrogen bonding and van der Waals forces.

A. A working definition of matter is that it takes up space, has mass, and has measurable properties. Matter is comprised of atomic, subatomic, and elementary particles.

B. Electrons are key to defining chemical and some physical properties, reactivity, and molecular structures. Repeating (periodic) patterns of physical and chemical properties occur among elements that define groups of elements with similar properties. The periodic table displays the repeating patterns, which are related to the atom's outermost electrons. Atoms bond with each other to form compounds.

C. In a chemical reaction, one or more reactants are transformed into one or more new products. Many factors shape the nature of products and the rates of reaction. 

D. Carbon-based compounds are building-blocks of known life forms on earth and numerous useful natural and synthetic products.

Hydrogen Bonding and DNA Stability

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