"This reaction won't proceed."
Kana showed her lab notebook.
Milia confirmed. "Bad combination of electron donor and acceptor."
"Bad?"
Rei explained. "The electron donor is troubled."
"Troubled?" Kana tilted her head.
"Wants to give electrons but the other won't accept them."
Toma laughed. "Rejected?"
"In a way," Rei acknowledged.
Milia drew a diagram. "Let's look at redox potentials."
"Potentials?"
"An indicator of tendency to release or accept electrons."
Rei showed a table. "Standard redox potential. More negative values mean easier to give electrons."
"So this donor is?"
"-0.32V. Relatively easy to give."
"But the acceptor?"
"-0.45V. Even more negative."
Kana understood. "The acceptor wants to give more than the donor wants to receive?"
"Exactly. So the reaction won't proceed."
Toma was confused. "Electrons flow from high to low potential?"
"Opposite. Electrons flow from low to high potential," Rei corrected.
"Opposite of water flowing from high to low?"
"Yes. Because electrons are negatively charged."
Milia supplemented. "Potential difference is the driving force. If ΔE > 0, reaction is spontaneous."
"In this case?"
"ΔE = -0.32 - (-0.45) = +0.13V. Positive so... wait?"
Rei laughed. "You had the sign backwards. Actually, ΔE = -0.13V"
"Negative, so won't proceed."
Kana was convinced. "Why electron donors are troubled."
"The other won't accept them."
Toma asked. "So what should we do?"
"Choose appropriate acceptor," Milia answered.
"An acceptor with higher potential?"
"Yes. Oxygen is +0.82V. Creates large potential difference."
Rei calculated. "ΔE = 0.82 - (-0.32) = 1.14V. This will react."
Kana wrote in her notebook. "Electrons flow according to potential difference."
"And that flow becomes energy."
Milia gave a biological example. "Look at the electron transport chain."
"Mitochondria?"
"Starts from NADH. Potential is -0.32V."
Rei continued. "Complex I → CoQ → Complex III → Cyt c → Complex IV → O₂"
"At each step, potential increases?"
"Yes. A staircase electrons descend."
Toma understood. "And oxygen waits at the end."
"Highest potential. Final acceptor."
Kana asked. "What if it stops midway?"
"Electrons can't be passed. Donors get stuck."
Milia showed an example. "Cyanide poisoning. Inhibits Complex IV."
"Then?"
"Electrons can't reach oxygen. Upstream donors clog up."
Rei added. "Respiration stops. Fatal."
Kana said sadly. "If electrons can't be passed, death."
"Because electron flow is life."
Toma offered another perspective. "Other reasons donors are troubled?"
"Steric hindrance," Milia answered.
"Shapes don't match?"
"Yes. If molecules can't approach, electron transfer can't occur."
Rei explained. "Protein recognition. Reaction only in specific orientations."
"Key and lock?"
"Exactly. Even if potentials match, reaction won't occur if shapes don't match."
Kana thought. "Electron donors have it tough."
"Must choose partner, match shapes, ensure potential difference."
Milia smiled. "The molecular world also depends on relationships."
Toma murmured. "Rejected or accepted."
"But when meeting the right partner, beautiful reactions occur."
Rei said quietly. "When electron donors are troubled. That's when reaction conditions don't align."
Kana smiled. "But when conditions align, energy is born."
"That's biochemistry's beauty."
The three quietly felt the troubles of invisible electrons.