Evolutionary biologists have always used a broad range of modern organisms to infer the characteristics that ancestral organisms may have possessed. Genomic sequences are now available for an increasing number of species, and scientists studying evolutionary processes can take advantage of this enormous amount of data to bring evolution into […]

Multiple choice  SOLUTIONS 1. The difference in RNA bases compared to DNA bases is A) RNA contains A instead of T. D) RNA contains A instead of U. B) RNA contains U instead of G. E) None of the above. C) RNA contains U instead of T. 2. What is […]

Q1. An elderly man has been receiving weekly injections of vitamin B12 ever since nearly all of his stomach was removed 6 months ago due to stomach cancer. Why is he receiving the vitamin injections? Why can’t the vitamin be delivered in tablet form? What is function of the vitamin […]

lex A is an E. coli gene whose product regulates the transcription of certain target genes that are located at different positions in the bacterial chromosome. Identified target genes appear to be involved in DNA repair and recombination. Under normal conditions, the LexA protein binds near and represses transcription of […]