Plasmids in bacterial cells are correctly defined as:
Answer and explanation
Correct answer: A. Small, circular, double-stranded extra-chromosomal DNA molecules capable of autonomous replication
- Step 1: Bacteria have a primary genomic DNA region known as the nucleoid, containing a large circular chromosome.
- Step 2: Many bacterial strains also harbor smaller, autonomous, circular double-stranded DNA molecules termed plasmids.
- Step 3: Plasmids replicate independently of genomic DNA and often encode non-essential beneficial traits, such as antibiotic resistance or bacteriocin production.
Answer
Small, circular, double-stranded extra-chromosomal DNA molecules capable of autonomous replication.
Why not the others: Linear single-stranded RNA molecules describes viral genomes or mRNA; Infolded mesosomal invaginations are plasma membrane structures involved in cell wall synthesis; Polysaccharide storage granules are inclusion bodies (e.g., glycogen granules).
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