Biochemists generally have much more chemistry than biology as their focus. Although most assume that the systems they study evolved, many are quite ignorant about evolution. Jokes about the ignorance of actual organisms on the part of molecular biologists are fairly popular.
Biochemistry is still in the process of discovering complexity.
As of yet, very few have tried to explain complex systems, so lack of explanations in the literature doesn't say much about whether explanation is possible. One day a shepherd was leading his flock across a road. The astonished shepherd admitted that was the correct number, and told the motorist to pick the sheep he wanted. The motorist's jaw dropped as he confirmed that the shepherd was correct.