Adenosine, guanosine, thymidine, uridine, cytidine are all ____ but adenylic acid, guanylic acid, uridylic acid, cytidylic acid are _______.

Options

A. nucleotides, nucleosides
B. nucleosides, nucleotides
C. nucleotides, nucleic acids
D. nucleosides, nucleic acid

Answer

To solve the question, we need to identify the classifications of the given compounds: adenosine, guanosine, thymidine, uridine, cytidine, and adenylic acid, guanylic acid, uridylic acid, cytidylic acid.

### Step-by-Step Solution:

1. **Understanding Nucleosides**:
- Nucleosides are composed of a nitrogenous base (adenine, guanine, thymine, uracil, or cytosine) and a sugar (ribose or deoxyribose).
- Examples of nucleosides include adenosine (adenine + ribose), guanosine (guanine + ribose), thymidine (thymine + deoxyribose), uridine (uracil + ribose), and cytidine (cytosine + ribose).

2. **Understanding Nucleotides**:
- Nucleotides consist of a nucleoside (nitrogenous base + sugar) plus one or more phosphate groups.
- Examples of nucleotides include adenylic acid (adenosine + phosphate), guanylic acid (guanosine + phosphate), uridylic acid (uridine + phosphate), and cytidylic acid (cytidine + phosphate).

3. **Classifying the Given Compounds**:
- The first group (adenosine, guanosine, thymidine, uridine, cytidine) consists of nucleosides.
- The second group (adenylic acid, guanylic acid, uridylic acid, cytidylic acid) consists of nucleotides.

4. **Final Answer**:
- Therefore, the correct answer to the question is:
- Adenosine, guanosine, thymidine, uridine, cytidine are all **nucleosides** but adenylic acid, guanylic acid, uridylic acid, cytidylic acid are **nucleotides**.

### Summary:
- **Answer**: Adenosine, guanosine, thymidine, uridine, cytidine are all **nucleosides** but adenylic acid, guanylic acid, uridylic acid, cytidylic acid are **nucleotides**.