Which statement correctly compares nucleic acids and carbohydrates?
A) They both contain phosphorus, but only nucleic acids contain hydrogen.
B) They both contain carbon, hydrogen, and oxygen in a 1:2:1 ratio.
C) They both contain carbon, but only carbohydrates contain oxygen.
D) They both contain carbon, but only nucleic acids contain phosphorous.
The Correct Answer and Explanation is :
The correct answer is D) They both contain carbon, but only nucleic acids contain phosphorus.
Explanation:
Nucleic acids and carbohydrates are both essential biomolecules but have different structures, functions, and elemental compositions.
1. Nucleic Acids:
Nucleic acids, such as DNA and RNA, are composed of nucleotides, which consist of three main components: a phosphate group, a five-carbon sugar (either deoxyribose in DNA or ribose in RNA), and a nitrogenous base. The defining feature of nucleic acids is the presence of phosphorus in the phosphate group, which is critical in linking nucleotides together through phosphodiester bonds. Nucleic acids also contain the elements carbon, hydrogen, oxygen, and nitrogen.
2. Carbohydrates:
Carbohydrates are primarily composed of carbon, hydrogen, and oxygen in the general formula of (CH₂O)ₙ, where “n” represents the number of repeating units (monomers). Simple sugars like glucose, for instance, follow this 1:2:1 ratio of carbon to hydrogen to oxygen. Carbohydrates are classified into monosaccharides, disaccharides, and polysaccharides, depending on the number of sugar units. They serve as a primary energy source for organisms and play roles in structural functions.
Comparison:
- Common Elements: Both nucleic acids and carbohydrates contain carbon, hydrogen, and oxygen, but nucleic acids also contain nitrogen (in their nitrogenous bases) and phosphorus (in the phosphate group), whereas carbohydrates do not.
- Phosphorus Presence: Only nucleic acids contain phosphorus, making statement D correct. Carbohydrates lack phosphorus entirely.
- Carbon Presence: Both nucleic acids and carbohydrates contain carbon, one of the basic building blocks of organic molecules.
In conclusion, nucleic acids and carbohydrates share some elemental similarities, but nucleic acids are unique in their phosphorus content, while carbohydrates follow a simpler composition ratio.