Which of these would most likely change the number of chromosomes found in a cell? A. A pair of chromosomes does not separate when a cell divides.
B. A set of chromosomes is duplicated when a cell divides by mitosis.
C. A chromosome in a cell has a sequence of bases altered by a mutation.
D. A pair of chromosomes in a cell overlaps and exchanges genes during meiosis.

Adoctor is trying to diagnose a patient with dry skin. which of the following resources would be the most ? a magazine ad about soft skin a growth chart online articles about dry skin medical books

Use the drop down menus to match each example to the fossil topic discussed then to show how the fossil record gives evidence of evolution

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?