Though they are too small to see without a special microscope, atoms make up all of the substances around you. Like all matter, atoms have mass and volume. But atoms are extremely small. A water droplet, like the one hanging from the tip of the leaf in this picture, contains more than a billion trillion atoms! Which of the following is a true statement? A. Atoms do not have mass. B. Atoms can be seen with the naked eye. C. All atoms are the same. D. Atoms make up every substance around you.

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?

Which part of the cell is affected by the movement of molecules through diffusion, osmosis and active transport?

If a human has 23 pairs of chromosomes in every muscle cell of its body how many chromosomes will be in a human egg or sperm