Final answer:
Protons move faster in retinal due to photoisomerization, where photons cause double bonds to switch from cis to trans, straightening the hydrocarbon chain and facilitating faster proton movement.
Step-by-step explanation:
The proton moves faster in retinal due to the process called photoisomerization. This is a biochemical alteration where photons cause the double-bonded carbons within the retinal molecule to switch from a cis to a trans conformation. When retinal absorbs a photon, the 11-cis-retinal shape changes into all-trans-retinal, straightening the hydrocarbon chain and enabling the proton to move faster. This photoisomerization is crucial in the process of visual transduction within the retina, leading to the activation of a G protein that ultimately changes the membrane potential of the photoreceptor cells, affecting neurotransmitter release.