Final answer:
Glucose is a smaller molecule than starch, which is a polysaccharide composed of numerous glucose units. The size of glucose can potentially be assessed using membranes with varying pore sizes, while the sweeter taste of long-chewed starchy food is due to starch breakdown into glucose by salivary enzymes.
Step-by-step explanation:
Indeed, glucose is a smaller molecule than starch. Starch is a polysaccharide that is made up of many glucose units linked together by glycosidic bonds. In particular, starch is composed of two types of molecules, amylose and amylopectin. Amylose is an unbranched chain of glucose monomers connected by α-1,4 glycosidic linkages, while amylopectin has both α-1,4 and α-1,6 glycosidic linkages, with the latter existing at the branching points. When comparing sizes, glucose is indeed much smaller than starch, as starch molecules can consist of hundreds to thousands of glucose units.
To determine the exact size of glucose or any substance, one could use membranes with various pore sizes to see which pores allow the glucose to pass through. This could help approximate the size of a glucose molecule in nanometers (nm).
When you chew starchy food like saltine crackers, the starch begins to break down into glucose due to the action of salivary amylase in the mouth, explaining why the taste may change to sweet after chewing for some time. Lastly, it's worth clarifying that glucose is not mainly stored by lipids in the human body. Instead, glucose is stored in the form of glycogen in animals and starch in plants, as per the storage methods used by different organisms.