Resonance energy transfer

Definition

Resonance energy transfer is a process in which energy absorbed by one molecule is transferred to another molecule without the emission of photons. This mechanism plays a crucial role in photosynthesis, allowing for efficient energy transfer between pigments in light-harvesting complexes, which ultimately leads to the conversion of light energy into chemical energy.

5 Must Know Facts For Your Next Test

1. Resonance energy transfer is essential for maximizing light absorption efficiency in photosynthetic organisms, as it allows energy to move quickly between pigments.
2. This process typically occurs when two molecules are in close proximity, enabling the absorbed energy from one molecule to be transferred to another with a compatible electronic state.
3. Resonance energy transfer can occur through two main mechanisms: Förster resonance energy transfer (FRET) and Dexter energy transfer, each with distinct distances and characteristics.
4. The efficiency of resonance energy transfer is influenced by factors such as distance between molecules, spectral overlap of the donor and acceptor, and their relative orientation.
5. In plants, resonance energy transfer helps ensure that the energy captured by chlorophyll molecules is directed to the reaction center, where it can be utilized for photosynthesis.

Review Questions

• How does resonance energy transfer enhance the efficiency of light harvesting in photosynthetic organisms?
  • Resonance energy transfer enhances light harvesting by allowing the rapid transfer of absorbed energy from one pigment molecule to another, ensuring that the maximum amount of light energy is utilized. This process minimizes losses that might occur if each pigment were required to emit photons individually after absorption. By coordinating energy movement effectively among pigments, plants can optimize their ability to convert sunlight into chemical energy during photosynthesis.
• Compare and contrast Förster resonance energy transfer (FRET) and Dexter energy transfer in terms of mechanism and efficiency.
  • Förster resonance energy transfer (FRET) is a long-range process where energy is transferred between molecules via dipole-dipole interactions over distances typically ranging from 1 to 10 nanometers. In contrast, Dexter energy transfer involves direct electron exchange between molecules and generally occurs over much shorter distances (less than 1 nanometer). While FRET is highly efficient at larger distances due to its dependence on spectral overlap and orientation, Dexter transfer can be more efficient at closer ranges due to its reliance on wavefunction overlap.
• Evaluate the role of resonance energy transfer in the context of plant adaptation to varying light conditions.
  • Resonance energy transfer plays a crucial role in how plants adapt to different light environments by optimizing light capture across a range of wavelengths and intensities. Under low-light conditions, this process enables plants to efficiently funnel absorbed light energy from multiple pigments to maximize photosynthetic efficiency. In high-light environments, certain pigments can dissipate excess energy as heat through non-photochemical quenching mechanisms, thereby preventing damage while still relying on resonance energy transfer for effective light utilization. This adaptability allows plants to thrive in diverse habitats.

Related terms

Chlorophyll: A green pigment found in plants that is vital for photosynthesis, absorbing light energy primarily in the blue and red wavelengths.

Light-harvesting complex: A group of proteins and pigments that capture and transfer light energy to the reaction center in photosynthesis.

Exciton: A bound state of an electron and an electron hole, representing a quantum mechanical entity involved in energy transfer processes within pigments.