Final answer:
Starch in plants functions primarily for storing energy, specifically in the form of glucose polymers named amylose and amylopectin. It provides a source of energy during germination and for other organisms that consume plants. Cellulose, unlike starch, has a structural role in plants.
Step-by-step explanation:
Starch serves as the primary storage form of energy in plants. It consists of two types of polymers: amylose, which is linear, and amylopectin, which is branched. Both are composed of glucose units. This storage is crucial as it provides energy for the plant during times when photosynthesis cannot meet immediate energy demands, such as during the night or periods of low light. Moreover, starch stored in seeds is vital for the germination process, supplying the developing embryo with the necessary energy.
In addition to being an energy reserve, the glucose from hydrolyzed starch is a fundamental dietary carbohydrate for both humans and animals. It is ingested and then hydrolyzed by enzymes like salivary amylases into simpler sugars like maltose and glucose, which are absorbed by the cells.
Although starch's main function is energy storage, it is distinct from cellulose, another glucose polymer in plants, which has a structural role in the plant cell walls.