If you were given a single tiny chunk of a nucleic acid strand and asked if it was DNA or RNA?

Question

what things would you look for to tell?

Answer 1

DNA = two strands (hence DEO in deoxynucleic acid means 2)

RNA = just one strand

Answer 2

Attempt to amplify the unknown material first with reverse transcription as when making a cDNA library from mRNA or total RNA. I would do it using random hexanucleotide primers plus  oligo(dT) priming in case there had been degradation to the polyA tail.  If it is RNA the first strand reaction will produce a cDNA template. Remove a small aliquote from the reaction to run on a gel, later, to check if any amplification occurred at this step.

If the unknown nucleic acid is DNA it will be amplified in the second strand PCR reaction using Taq and fresh upstream and downstream DNA primers.  Again remove a sample to run on a gel. Sequence remaining PCR product.

For each of these reactions a known control template would have been used as control for each reaction. A known mRNA and a total RNA sample for the first strand RT-PCR plus a DNA sample run through both first strand and second strand synthesis. All would be sampled as the unknown was. Run all samples on gel with size markers to see controls worked and which PCR reaction produced product from the unknown.

http://www.piercenet.com/Proteomics/brow...

Amplify RNA

http://www.pubmedcentral.nih.gov/article...

Alternate possible test:

RNA in RNase free buffer can be read with a spec for light absorbance at 260/280 ratio. For DNA the 260/280 is 1.8 and for RNA the 260/280 is 2.0 but you do need enough material to get a reading.

In reality just wait 3 minutes and any tiny fragment of isolated RNA would be degraded unless correctly handled. RNase A is ubiquitous and even boiling does not denature it so handling RNA is tricky.

Answer 3

Double stranded = DNA

Single stranded  = RNA

Deoxyribose is the sugar in DNA

Ribose is the sugar in RNA

Cytosine and Thymidine are the nitogenous pyrimidine bases in DNA.

Cytosine and Uracil are the nitrogenous pyrimidine bases in RNA

Both DNA and RNA have the nitrogenous purine bases Adenine and Guanine.