Answer to Question 1
Whether amino acids come from animal or plant sources makes little difference from a nutritional standpoint. From a health standpoint, amino acids from plant sources are often accompanied by fiber, carbohydrates, phytochemicals, and generally healthy fats whereas amino acids from animal sources are usually accompanied by unhealthy fats like saturated fat (a major exception is seafood). Therefore, plant-based protein often has some health advantages over animal based protein.
Answer to Question 2
Another substance found in the plants we eat is fiber. Although technically a carbohydrate, fiber is different from starchy carbohydrates because it consists of the plant's indigestible cellulose components. For the purpose of this chapter, fiber is treated as a separate food component rather than as a carbohydrate. Fiber is beneficial to our health but provides no life-sustaining energy.
animal cell
Plant
Tracing the Source of a Water-Borne Disease
Validation of the genetic code by amino acid sequence analysis of T4 phage lysozyme mutants
Wheat Plant
Red Spotted Newt (Notophthalmus v. viridescens), New Hampshire state animal.