11.  In prokaryotes, translation is beginning at the 5′ end while the 3′ end is still being synthesized. In eukaryotes, processing (capping, splicing) is taking place at the 5′ end while the 3′ end is still being synthesized.

17.  Yes. Both replication and transcription are performed by large, multisubunit molecular machines (the replisome and RNA polymerase II, respectively), and both require helicase activity at the fork of the bubble. However, transcription proceeds in only one direction and only one DNA strand is copied.

19. 

24.  Self-splicing introns are capable of excising themselves from a primary transcript without the need of additional enzymes or energy source. They are one of many examples of RNA molecules that are catalytic, and, for this property, they are also known as ribozymes. With this additional function, RNA is the only known biological molecule to encode genetic information and catalyze biological reactions. In simplest terms, life possibly began with an RNA molecule or group of molecules that evolved the ability to self-replicate.

29.  Double-stranded RNA, composed of a sense strand and a complementary antisense strand, can be used in C. elegans (and likely all organisms) to selectively prevent the synthesis of the encoded gene product (a discovery for which the 2006 Nobel Prize in Physiology or Medicine was awarded). This process, called gene silencing, blocks the synthesis of the encoded protein from the endogenous gene and is thus equivalent to “knocking out” the gene. To test whether a specific mRNA encodes an essential embryonic protein, inject the double-stranded RNA produced from the mRNA into eggs or very early embryos, thus activating the RNAi pathway. The effects of knocking out the specified gene product can then be followed by observing what happens in these embryos compared with controls. If the encoded protein is essential, embryonic development should be perturbed when your gene is silenced.