cDNA probes are copied from the messenger RNA molecules with the help of

Options

A. Reverse transcriptase
B. DNA polyermase
C. Restriction enzymes
D. Adenosine deaminase

Answer

To solve the question "cDNA probes are copied from the messenger RNA molecules with the help of," we will analyze the options provided and identify the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding cDNA**:
- cDNA stands for complementary DNA. It is synthesized from a messenger RNA (mRNA) template through a process called reverse transcription.

**Hint**: Remember that cDNA is derived from mRNA, which means we need a mechanism to convert RNA back to DNA.

2. **Identifying the Process**:
- The process of reverse transcription is crucial here. This is where the mRNA is used as a template to synthesize cDNA.

**Hint**: Think about which enzyme is responsible for synthesizing DNA from an RNA template.

3. **Evaluating the Options**:
- **Option 1: Reverse Transcriptase**: This enzyme catalyzes the synthesis of cDNA from mRNA.
- **Option 2: DNA Polymerase**: This enzyme synthesizes DNA but does not use RNA as a template; it works on existing DNA strands.
- **Option 3: Restriction Enzymes**: These enzymes cut DNA at specific sequences and do not play a role in synthesizing cDNA.
- **Option 4: Adenosine Deaminase**: This enzyme modifies adenine but is not involved in the synthesis of cDNA.

**Hint**: Focus on the function of each enzyme and its role in nucleic acid synthesis.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Reverse Transcriptase**, as it is the enzyme that facilitates the conversion of mRNA into cDNA.

**Final Answer**: cDNA probes are copied from the messenger RNA molecules with the help of **Reverse Transcriptase**.