Primers are chemically synthesised

Options

A. Oligosaccharides
B. Oligonucleotides
C. Oligopeptides
D. Polypeptides

Answer

### Step-by-Step Solution:

1. **Understanding the Term "Primer":**
- Primers are short sequences of nucleotides that are essential in the process of DNA replication and amplification.

2. **Identifying the Type of Molecule:**
- Primers are specifically classified as oligonucleotides. The prefix "oligo-" means "few" or "small," indicating that these molecules consist of a small number of nucleotides.

3. **Chemical Composition of Primers:**
- Primers are made up of either deoxyribonucleotides (DNA) or ribonucleotides (RNA). This means they can be composed of DNA or RNA sequences, but in the context of PCR (Polymerase Chain Reaction), they are typically DNA primers.

4. **Function of Primers:**
- Primers bind to the complementary sequences at the three prime end of the template DNA. This binding is crucial for the initiation of DNA synthesis.

5. **Hybridization Process:**
- The process of hybridization occurs when the primers anneal to the target DNA, allowing DNA polymerase to extend the primers and synthesize new DNA strands.

6. **Orientation of Primers:**
- Primers are oriented in such a way that their ends face each other, which facilitates the synthesis of DNA towards one another.

7. **Application of Primers:**
- Primers are widely used in techniques like PCR to amplify small amounts of DNA, making them essential tools in molecular biology.

8. **Conclusion:**
- Based on the above understanding, the correct answer to the question is that primers are chemically synthesized **oligonucleotides**.

### Final Answer:
Primers are chemically synthesized **oligonucleotides**.

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