Hydrogen bonds connect donors and acceptors to organize biomolecules.distance 0.20 nm · angle 180° · stability 100%

Hydrogen Bonds in Biomolecules

Donors, acceptors, DNA, proteins, hydration, and molecular recognition

Workspace

Biomolecular hydrogen-bond laboratory

Interaction controls

H···acceptor distance0.20 nm

D–H···A angle180°

Temperature300 K

Environment

Biomolecular pair

Simulation speed1×

Camera zoom1×

Molecular sound effects

Visual experiments

Live evidence

Geometry score100%

Interaction strength100%

Active bonds1

StabilityHigh

Relationships

D–H···A requires donor, hydrogen, and acceptor

S ≈ exp(−((r − r₀) ÷ σ)²) × cos²(180° − θ)

Many weak interactions → cooperative stability

Near-linear geometry and favorable distance strengthen the interaction.

Object focus

Tap a donor, hydrogen, acceptor, dotted bond, base pair, protein segment, or water molecule.

Teacher presets

Teacher narration

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Narrator

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Chapters

Learning objectives

Identify hydrogen-bond donors and acceptors.
Relate interaction strength to distance and direction.
Explain A–T and G–C base pairing in DNA.
Trace hydrogen bonds in alpha helices and beta sheets.
Predict how water, temperature, and protonation affect bonding.

Key relationships

Donor: commonly O–H or N–H.

Acceptor: commonly O or N with available electron density.

DNA: A–T has two principal bonds; G–C has three.

Proteins: backbone C=O accepts and N–H donates.

Suggested experiments

Bend the donor–hydrogen–acceptor angle.
Increase distance beyond the favorable region.
Compare A–T and G–C pairing.
Raise temperature and watch cooperative bonds fluctuate.

Questions for exploration

Why are hydrogen bonds directional?
How can many weak bonds stabilize a large structure?
Why does water both stabilize and compete for these bonds?

Seven-question hydrogen-bond check

Answer all seven questions.

Teacher whiteboard

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