PCAT Microbio Question

[perform02]

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This question's from one of practice tests I have. I thought the bacterial genome consists of 'one single-stranded' DNA? but the answer was 1, and it seems like there can be both?

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Q:The bacterial genome consists of:

1.one double-stranded, circular molecules of DNA
2. one single-stranded, circular molecules of DNA
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If someone can clarify on this question, I'd be appreciated!

 

[Incitatus]

Bacteria have a circular chromosome, but it is still double stranded.

They also often have plasmids that would technically qualify as part of the genome, but not part of the chromosome.

 

[pharmschooler]

This question's from one of practice tests I have. I thought the bacterial genome consists of 'one single-stranded' DNA? but the answer was 1, and it seems like there can be both?

-----------------------------------
Q:The bacterial genome consists of:

1.one double-stranded, circular molecules of DNA
2. one single-stranded, circular molecules of DNA
-----------------------------------

If someone can clarify on this question, I'd be appreciated!

If the DNA was single stranded, it would be "sticky" to the rest of the DNA in the circle (ie, it could H bond to the complementary base pairs of the rest of the DNA) or it could more easily be attacked/attack other nearby molecules. It needs to be double stranded (complementarily base-paired) to retain its structure.