DGH

 96. Cloning to produce embryonic stem cells is called 

D) therapeutic cloning. 

 97. Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off. 

 D) regulatory proteins 

98. Enhancers are 

 C) the site on DNA to which activators bind.

 99. Silencers are sites in DNA that 

 C) bind repressor proteins to inhibit the start of transcription. 

100. RNA splicing involves the 

 C) removal of introns from the molecule.

. 101.The coding regions of a gene (the portions that are expressed as polypeptide sequences) are called 

 B) exons. 

 102.Which of the following permits a single gene to code for more than one polypeptide? 

 B) alternative RNA splicing