Appropriate regulation of different genes is accomplished by different combinations of a limited repertoire of transcription factors at each gene, a mechanism referred to as _____________________.
举一反三
- Some genes can be expressed in different ways to generate multiple gene products from a single segment of DNA.
- In positive regulation, most of the genes are usually inactive (that is, RNA polymerases do not bind to the promoters) and the cell synthesizes only the activator proteins needed to promote transcription of the subset of genes required in the cell at that time.
- The Olympic Games held ______. A: each time in different city B: mostly in Europe C: in different cities in Greece D: in the capitals of different countries
- Choose the appropriate letters A-C. People usually have（） A: a mixture of fingertip patterns which are identical on each hand. B: a mixture of patterns with similarities between hands. C: a different pattern on each hand.
- 中国大学MOOC: Why do people in different countries greet each other in different ways? ( )