Which of the following statements describes the process of transformation in bacteria?
A) A strand of DNA is created from an RNA molecule. B) A strand of RNA is created from a DNA molecule. C) Bacterial cells are infected by a phage DNA molecule. D) External DNA is taken into a cell, becoming part of the cell's genome.
In DNA polymerization, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer?
A) the 5' phosphate B) C6 C) the 3' OH D) a nitrogen from the nitrogen-containing base
Frederick Griffith heat-killed a culture of pathogenic bacteria. He split the sample and injected half of it into mice. The mice lived. He then mixed the other half of the sample with a living, nonpathogenic bacteria strain and injected the mixture into mice. The mice died. Which of the following describes a treatment that would help clarify interpretation of these data?
A) injecting another population of mice with the original, heat-killed pathogenic bacteria B) heat killing the mixed sample and injecting it into mice C) examining tissue from the dead mice (injected with mixed sample) for the presence of pathogenic bacteria D) culturing bacteria from blood isolated from the living mice (injected with heat-killed pathogenic bacteria)