Hydrophobic organic molecules that are part of the electron

Hydrophobic organic molecules that are part of the electron transport chain; freely diffuses in lipid bilayer instead of associating with proteins:

Solution

Phospholipid bilayer in mitochondria / cell membrane has hydrophilic head and hydrophobic tail. Hydrophilic head of one layer facing outside and other layer is facing inside. Hydrophobic tails facing each other and forms the middle portion of the bilayer where proteins are inserted to form channels/ pores etc. Hydrophobic tails cluster together to form energetically favourable structure. Hydrophobic molecules / small uncharged particles pass easily across the lipid bilayers due to hydrophobic nature of the bilayer membrane (hydrophobic attracts hydrophobic). These molecules move inside or outside on the bases of concentration gradient due to diffusion process. Large molecules/ hydrophilic molecules/ charges molecules have various other ways to enter in the cells like channels, pores, active / passive transports etc.