What was Marshall Nirenberg and Heinrich Matthaei’s contribution to our current understanding of the genetic code? discovery of codons
discovery and extraction of DNA
creation of a model of DNA
creation of Photo 51

Select the correct answer. a chestnut-colored horse mates with a white-colored horse to produce a brown and white spotted offspring. what is the type of inheritance pattern?

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?