PCR needs-

Options

A. 2 sets of primers
B. Taq polymerase
C. Nucleotide as raw materials
D. All

Answer

### Step-by-Step Solution for the Question: "PCR needs-"

1. **Understanding PCR**:
- PCR stands for Polymerase Chain Reaction, a technique used to amplify DNA in vitro.
- It allows for the replication of specific DNA fragments.

2. **Template DNA**:
- The first requirement for PCR is a template DNA. This is the DNA that you want to amplify.

3. **Polymerase Enzyme**:
- The second requirement is a polymerase enzyme.
- The specific enzyme used in PCR is Taq polymerase, which is derived from the thermophilic bacterium Thermus aquaticus.
- Taq polymerase is thermostable, meaning it can withstand the high temperatures used during PCR.

4. **Primers**:
- PCR requires two sets of primers: a forward primer and a reverse primer.
- The forward primer binds to the start of the target DNA sequence, while the reverse primer binds to the end of the target sequence.
- This allows for the amplification of both strands of the DNA.

5. **Nucleotides**:
- The fourth requirement is nucleotides, which are the building blocks of DNA.
- In PCR, we need deoxynucleotide triphosphates (dNTPs), which include adenine (dATP), cytosine (dCTP), guanine (dGTP), and thymine (dTTP).

6. **Summary of Requirements**:
- Therefore, the complete list of requirements for PCR includes:
- Template DNA
- Taq polymerase (or another thermostable polymerase)
- Two sets of primers (forward and reverse)
- Nucleotides (dATP, dCTP, dGTP, dTTP)

7. **Final Answer**:
- The correct answer to the question "PCR needs-" is "all of the above," as it encompasses all the necessary components for the PCR process.