Question

multiple choice question
small, double - stranded, circular pieces of dna found in addition to the bacterial chromosome are called ______.
options: plasmids; ribosomes; chromatids; nucleoids

Explanation:

To solve this, we analyze each option:

• Plasmids: Small, double - stranded, circular DNA molecules that exist independently of the bacterial chromosome. This matches the description in the question.
• Ribosomes: These are cellular structures involved in protein synthesis, not DNA molecules. So this option is incorrect.
• Chromatids: These are part of a chromosome (in eukaryotic cells, mainly) and are not the extra circular DNA in bacteria. So this option is incorrect.
• Nucleoids: The nucleoid is the region in a bacterial cell where the main bacterial chromosome is located, not the extra small circular DNA. So this option is incorrect.

Answer:

A. plasmids