nucleotides and nucleic acids Flashcards
what type of reaction is aspartate to glutamate?
conservative substitution
what type of base analogues does DNA sequences use?
fluorescent
What is the mechanism by which dideoxyribonucleotides cause chain termination in these reactions in Sanger sequencing methods?
Dideoxyribonucleotides can be incorporated into DNA but prevent subsequent chain elongation.
How does a nucleotide differ from a nucleoside?
A nucleotide is a nucleoside with a phosphate ester-linked to the sugar.
How many amino acids are there in the standard genetic code?
20
In which direction does mRNA synthesis by RNA polymerase occur?
5’ → 3’
what are ribosomes are composed of?
rRNA and protein
what is the difference in RNA bases compared to DNA bases?
RNA contains U instead of T.
what feature(s) of DNA were deduced by Watson and Crick?
- the bases are nearly perpendicular to the axis
- the pyrimidine and purine bases lie on the inside of the helix
- two antiparallel polynucleotide chains coiled in a helix around a common axis
what is gene expression?
The flow of genetic information from DNA to protein
Which molecules that are produced during transcription carry information for use as a template during translation?
mRNA
what is the degeneracy of the genetic code?
Some amino acids are specified by multiple codons; these codons usually differ only at the third position.
Which of the following best describes the structural backbone of nucleic acids?
… – phosphate – sugar – phosphate – sugar – …
what is not a standard base found in RNA?
thymine
which of the following most accurately describes the charge state of DNA under physiological conditions?
Roughly uniformly negatively charged along its length
