Energy Carriers in Photosynthesis

Overview

Photosynthesis and respiration involve the movement of electrons (e-) and hydrogen ions (protons or H+). These processes are essential for energy transfer in cells.

• Oxidation: A molecule loses electrons.
• Reduction: A molecule gains electrons.

ATP (Adenosine Triphosphate)

• ATP is an energy carrier.
• It traps energy and transports it from where it is produced to where it is needed.

Revision Question

• What occurs during reduction in cells?
  • Gain of electrons
  • Loss of hydrogen ions
  • Release of energy
  • Absorption of oxygen

ADP (Adenosine Diphosphate)

• ADP is a low energy molecule.
• When ADP combines with a phosphate (P), energy is trapped in the bond, forming ATP.
• Breaking this bond releases the stored energy.

Phosphorylation

• The process where ADP + P + energy forms ATP.
  • ATP → ADP + P + Energy

Revision Question

• What happens when ADP combines with phosphate?
  • Energy is released as heat
  • It forms ATP and stores energy
  • ADP becomes a protein
  • It is converted to glucose

NADP (Nicotinamide Adenine Dinucleotide Phosphate)

• NADP is involved in photosynthesis.
• Gains 2 electrons (2e) and an H ion to become NADPH.

Revision Question

• What is produced when NADP gains electrons?
  • NADH
  • NADPH
  • ATP
  • ADP

NADPH

• NADPH is a high-energy electron and proton carrier.
• Transports electrons and H ions to where they are needed in the cell.
• Uses its electrons and H ions to make glucose in photosynthesis.

Revision Question

• What role does NADPH play in photosynthesis?
  • Carries oxygen in the cell
  • Transports glucose to mitochondria
  • Provides electrons for ATP synthase
  • Delivers electrons for glucose synthesis

For further reading, explore topics such as the role of light, water, CO2, and chlorophyll in photosynthesis.