DNA primer

Definition

A DNA primer is a short, single-stranded sequence of nucleotides that provides a starting point for DNA synthesis. Primers are essential in various molecular biology techniques such as PCR and DNA sequencing.

5 Must Know Facts For Your Next Test

1. Primers are typically 18-24 nucleotides long to ensure specificity and efficient binding.
2. They anneal to the template DNA strand by complementary base pairing.
3. Primers are necessary for DNA polymerases as these enzymes cannot start replication de novo; they can only add nucleotides to an existing strand.
4. In PCR, primers define the boundaries of the DNA region to be amplified.
5. The melting temperature (Tm) of a primer is crucial for determining the annealing temperature during PCR.

Review Questions

Related terms

DNA Polymerase:

An enzyme that synthesizes new strands of DNA complementary to the template strand.

PCR (Polymerase Chain Reaction):

A technique used to amplify small segments of DNA using repeated cycles of denaturation, annealing, and extension.

Annealing Temperature: The temperature at which primers bind or 'anneal' to their complementary sequences on the template DNA during PCR.