Question

adenine molecule
nine the structural formula of adenine:
what is the molecular formula of adenine?
what element is in adenine that is not in carbohydrates (such as ribose)?
what element is in ribose (a carb) that is not in adenine?
iii. phosphoric acid molecule
examine the structural formula phosphoric acid.
phosphoric acid is much like the phosphate groups
in atp. note: the letter \p\ represents the
element phosphorus.
what is the molecular formula of phosphoric
acid?

Explanation:

Step1: Count atoms in adenine

Count the number of \(C\), \(H\), \(N\) atoms. There are \(5\) \(C\) (black circles), \(5\) \(H\), and \(5\) \(N\). So molecular formula is \(C_5H_5N_5\).

Step2: Count atoms in phosphoric acid

Count \(H\), \(P\), \(O\) atoms. There are \(3\) \(H\), \(1\) \(P\), and \(4\) \(O\). Molecular formula is \(H_3PO_4\).

Step3: Element in adenine not in carbohydrates

Carbohydrates (like ribose) have \(C\), \(H\), \(O\). Adenine has \(N\) which is not in them.

Step4: Element in ribose not in adenine

Ribose has \(O\) (as it's \(C_5H_{10}O_5\)) which adenine (\(C_5H_5N_5\)) lacks.

Answer:

• Molecular formula of adenine: \(C_5H_5N_5\)
• Molecular formula of phosphoric acid: \(H_3PO_4\)
• Element in adenine not in carbohydrates: Nitrogen (\(N\))
• Element in ribose not in adenine: Oxygen (\(O\))