Plasmids

Definition

Plasmids are small, circular, double-stranded DNA molecules that exist independently of the chromosomal DNA in bacteria. They often carry genes beneficial for survival, such as antibiotic resistance.

5 Must Know Facts For Your Next Test

1. Plasmids can replicate independently of the bacterial chromosome.
2. They often carry genes that confer advantages like antibiotic resistance or virulence factors.
3. Plasmids are commonly used as vectors in genetic engineering to insert new genes into organisms.
4. Horizontal gene transfer via plasmids can spread drug resistance among bacterial populations.
5. Some plasmids contain origins of replication that are recognized by the host's replication machinery.

Review Questions

• What role do plasmids play in antibiotic resistance?
• How are plasmids used in genetic engineering?
• Explain the process and significance of horizontal gene transfer involving plasmids.

Related terms

Transformation: The uptake and incorporation of external DNA by a cell.

Conjugation: A process where genetic material is transferred between bacterial cells through direct contact.

Antibiotic Resistance Genes: Genes carried on plasmids that provide bacteria with resistance to antibiotics.