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

A hydrogen bond is an intermolecular electrostatic attraction between a hydrogen atom and an electronegative atom with a lone pair of electrons.
In a polar molecule, like hydrogen fluoride or HF, ammonia or NH3, and water or H2O, the fluorine, nitrogen, or oxygen atom is more electronegative than hydrogen.
The more electronegative atom attracts bonding electron pairs more strongly than hydrogen. This results in unequal electron distribution in the bond, giving the electronegative atom a partial negative charge and the hydrogen atom a partial positive charge.
The partial positive charge on the hydrogen atom enables it to attract non-bonded pair of electrons of an electronegative atom in its vicinity, forming a hydrogen bond.
Hydrogen bonds provide structural stability to various biological molecules, including DNA.

waterstofbruggen

Een waterstofbrug ontstaat wanneer een zwak positief waterstofatoom dat al gebonden is aan een elektronegatief atoom (bijvoorbeeld de zuurstof in het watermolecuul), wordt aangetrokken door een ander elektronegatief atoom van een ander polair molecuul, zoals water (H_2O), waterstoffluoride (HF) of ammoniak (NH_3). Het grote elektronegativiteitsverschil tussen het H-atoom (2.1) en het atoom waaraan het gebonden is (4.0 voor een F-atoom, 3.5 voor een O-atoom of 3.0 voor een N-atoom), in combinatie met de zeer kleine grootte van een H-atoom, resulteert in een ongelijke verdeling van ladingen tussen het waterstofatoom en het elektronegatieve atoom. Dit zorgt ervoor dat het waterstofatoom gedeeltelijk positief wordt en het elektronegatieve atoom gedeeltelijk negatief. Moleculen met F-H, O-H of N-H groepen worden daarom sterk aangetrokken door vergelijkbare groepen van nabijgelegen moleculen en vormen een bijzonder sterke dipool-dipool aantrekking die de waterstofbrug wordt genoemd.

Waterstofbruggen hebben een uitgesproken effect op de eigenschappen van vloeistoffen en vaste stoffen. Zo zijn het smeltpunt en het kookpunt van methylamine (CH_3NH_2) bijvoorbeeld hoger dan die van ethaan (CH_3CH_3), hoewel beide vergelijkbaar zijn qua grootte en massa. In tegenstelling tot ethaan bezit methylamine, een NH-groep, waardoor het waterstofbruggen kan vormen en de intermoleculaire krachten tussen moleculen kan vergroten, wat uiteindelijk leidt tot verhoging van het smelt- en kookpunt.

Waterstofbruggen komen veel voor in de natuur,zoals bij het DNA, dat genetische informatie bevat en in elk organisme wordt aangetroffen. Elk basenpaar van DNA wordt gevormd door waterstofbruggen via drie waterstofbruggen. Deze complementaire basenparing draagt bij aan de vorm en stabiliteit van de dubbele helixstructuur van DNA.



Dit artikel is aangepast van <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/">Openstax, Anatomy and Physiology 2e, Section 2.2: Chemical Bonds</a> and <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/">Openstax, Chemistry 2e, Section 10.1: Intermolecular Forces </a>

Waterstofbruggen

A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) ...

Education

JoVE Core

Anatomy and Physiology

Anatomie en fysiologie

Unit 1

Fundamentals of Chemistry

Grondslagen van de chemie

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

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

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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, ...

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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

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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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phase-transitions-vaporization-and-condensation

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phase-transitions-sublimation-and-deposition

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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

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The Electromagnetic Spectrum

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Interference and Diffraction

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The Quantum-Mechanical Model of an Atom

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SC.912.P.8.3

Elements: Chemical Symbols and Isotopes

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Ions and Ionic Charges

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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

Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside in ...

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

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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

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Bonding in Metals

Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Dr&#xFC;de called the ...

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 ...

Van der Waals Interactions

Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive 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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