A mutation that changes a codon that originally coded for an amino acid into a stop codon is a

A) frameshift mutation.
B) missense mutation.
C) silent mutation.
D) nonsense mutation.


D) nonsense mutation.

A mutation that changes a codon that originally coded for an amino acid into a stop codon is a nonsense mutation.

Biology & Microbiology

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Eukaryotes are ________.

A. often made of prokaryotic cells B. always multicellular C. often multicellular, sometimes unicellular D. always unicellular

Biology & Microbiology

Was their hypothesis supported by this experiment and why?

Bartel and Szostak hypothesized that among a large pool of RNA molecules, some of them may contain the enzymatic ability to catalyze a covalent bond between nucleotides; these can be selected for in the laboratory. The chart above shows the results from their experiment. The x-axis shows the original pool and 10 pools that were derived from their tagging of RNA with specific enzymatic functions; the y-axis shows the rate of phosphoester (covalent) bond formation.



A. Yes, because pools 1 to 10 show a continual increase in covalent bond formation.
B. Yes, there is a definite increase from the original pool to the second pool, but not from pool 8-10.
C. No, because there is only a slight increase from the original pool to the first experimental pool.
D. No, because this figure does not give sufficient data to make that assumption.

Biology & Microbiology

Quaternary structure of a protein refers to ________

A) the sequence of amino acids in a polypeptide B) alpha-helical or beta-sheet arrangements of protein structure C) three-dimensional coil of a polypeptide around itself D) the association of multiple polypeptide subunits to form a functional protein E) the number of amino acids in a polypeptide chain

Biology & Microbiology

Certain drugs use RNA interference as a mechanism of action.  What molecule would the active compounds of these drugs be composed of?

A. protein B. small ion C. steroid D. nucleic acid E. carbohydrate

Biology & Microbiology