Q - DNA

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Prep4USMLE Forum » USMLE Step 1 Forum » Histology & Molecular Biology

Q - DNA

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5 Posts

11/19/03 - 10:12 AM

The following double-stranded polynucleotide is diagramed with its terminal ends shown and with a relatively long midpiece indicated as a dashed line. The terminal ends are single-stranded where the bases are indicated.

CCTAGG-------
--------GGATCC

Which of the following statements is true?

A. Terninal repetition is not observed
B. The end sequences are palindromes
C.The polynucleotide is similar to intact plasmid DNA
D.5'-Exonuclease could not have produced the polynucleotide
E. The polynucleotide segment can form a circular piece of DNA

Ouli Maty
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11/19/03 - 05:07 PM

Could it be B palindromes. It looks like if you fold it in the middle, the bases would be similar.

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mjl1717
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11/30/03 - 11:37 AM

I agree with Maty, because it spells the same thing forward or backward like the word radar. (Just hope we can answer quickly and extrapolate on exam )

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mahendra
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12/02/03 - 02:42 PM

i think its B

Guest

12/14/03 - 09:34 PM

Correct answer is E.
"Lettered" ends are SINGLE-STRANDED, and complementary. Circular DNA can be formed.
When i posted this guestion, i'm sure i've represented it in a correct way - as single strands. But it appeared as dowble and confused you.
Sorry, probably it was my fault.

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