Which structural feature distinguishes $\mathrm{glucose}$ from $\mathrm{ribose}$ molecules?

• A. $\mathrm{Glucose}$ is a ketose, while $\mathrm{ribose}$ is an aldose.
• B. $\mathrm{Glucose}$ has a higher molecular weight than $\mathrm{ribose}$ due to additional $\mathrm{nitrogen}$ atoms.
• C. $\mathrm{Glucose}$ has $6$ carbon atoms, while $\mathrm{ribose}$ has $5$ carbon atoms.
• D. $\mathrm{Glucose}$ contains a furanose ring, while $\mathrm{ribose}$ contains a pyranose ring.

Answer: (C)

Verified step by step guidance

1. Identify the basic structure of glucose and ribose. Glucose is a hexose sugar, meaning it has six carbon atoms, while ribose is a pentose sugar, meaning it has five carbon atoms.
2. Understand the difference between aldoses and ketoses. Both glucose and ribose are aldoses, meaning they contain an aldehyde group.
3. Examine the molecular formula of glucose (C₆H₁₂O₆) and ribose (C₅H₁₀O₅) to confirm the number of carbon atoms in each molecule.
4. Recognize that the presence of a furanose or pyranose ring is not a distinguishing feature between glucose and ribose. Glucose typically forms a pyranose ring, while ribose can form a furanose ring.
5. Conclude that the primary structural feature distinguishing glucose from ribose is the number of carbon atoms: glucose has six, while ribose has five.