HIV, the virus that causes AIDS, depends on an enzyme called reverse transcriptase to multiply. Reverse transcriptase reads a molecule of RNA and creates a molecule of DNA from it. A molecule of AZT, an anti-AIDS drug, has a shape very similar to (but a bit different than) that of the DNA base thymine. Propose a model for how AZT inhibits HIV.

the wires in the toaster turning red and the toast crisping and turning brown

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.