MDCAT Biology MCQ #706

A molecular biologist compares the pentose sugars in DNA and RNA. Which chemical difference uniquely identifies the deoxyribose sugar in DNA?

MDCAT Biology MCQ #706

  1. Question 1

    Q1. A molecular biologist compares the pentose sugars in DNA and RNA. Which chemical difference uniquely identifies the deoxyribose sugar in DNA?

    • A) Presence of extra oxygen at C2
    • B) Absence of oxygen at C2
    • C) Presence of nitrogen at C3
    • D) Absence of carbon at C5

    Answer: Absence of oxygen at C2

    Explanation: Deoxyribose lacks an oxygen atom at the carbon 2 position. Ribose is tempting as it is the other pentose, but it has a hydroxyl group.