Which of the following nucleic acids is present in an organism having 70S ribosomes only ?

Options

A. Single stranded DNA with protein coat
B. Double stranded circular naked DNA
C. Double stranded DNA enclosed in nuclear membrane
D. Double stranded circular DNA with histone proteins

Answer

To solve the question "Which of the following nucleic acids is present in an organism having 70S ribosomes only?", we will follow these steps:

### Step 1: Understand the Context of 70S Ribosomes
- **70S ribosomes** are characteristic of prokaryotic organisms, such as bacteria. Eukaryotic organisms typically have 80S ribosomes. This means that if an organism has 70S ribosomes, it is likely a prokaryote.

### Step 2: Analyze the Options Given
- The options provided are:
1. Single-stranded DNA with protein coat
2. Double-stranded circular naked DNA
3. Double-stranded DNA enclosed in a nuclear membrane
4. Double-stranded circular DNA with histone proteins

### Step 3: Identify the Type of Genetic Material in Prokaryotes
- Prokaryotic organisms typically have their genetic material in the form of **naked DNA**, which is:
- **Double-stranded**
- **Circular**
- **Not enclosed in a nuclear membrane** (since prokaryotes do not have a defined nucleus)

### Step 4: Eliminate Incorrect Options
- **Option 1** (Single-stranded DNA with protein coat) is incorrect because prokaryotes do not have single-stranded DNA as their primary genetic material.
- **Option 3** (Double-stranded DNA enclosed in a nuclear membrane) is incorrect because prokaryotes do not have a nuclear membrane.
- **Option 4** (Double-stranded circular DNA with histone proteins) is incorrect because prokaryotic DNA is not associated with histone proteins; this is a feature of eukaryotic DNA.

### Step 5: Identify the Correct Answer
- The only option that fits the characteristics of prokaryotic genetic material is **Option 2: Double-stranded circular naked DNA**.

### Conclusion
- Therefore, the correct answer is **Option 2: Double-stranded circular naked DNA**.

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