Starch contains glucose monomers in linear forms as well as branched forms. This describes starch's structural arrangement as being composed of which types of chains?

• A. Linear and branched
• B. Cyclic only
• C. Branched only
• D. Random coils

Answer: (A)

The main concept here is that starch is made up of two glucose polymers: one is essentially linear, and the other is highly branched. Amylose is a long, mostly linear chain connected by α-1,4 glycosidic bonds, while amylopectin is a branched polymer with α-1,4 links in the linear portions and α-1,6 links at the branch points. This combination means starch consists of both linear and branched chains. The other options aren’t appropriate because cyclic refers to the ring form of individual glucose units (not the polymer architecture), branched-only ignores the linear component, and random coils aren’t the standard way we describe the chain types in starch.