Section 11.4 309 any of 7!/(2!2!) = 1260 RNA chains. The better estimate is 60 chains. In this case, we can find 36 Eulerian trails ending at A, each one beginning at U. Repeated labels on arcs mean that there are nine possible answers: UCAGGCUAAGUAGUAGUA, UCAGUAGGCUAAGUAGUA, UCAGUAGUAGGCUAAGUA, UAGGCUAAGUCAGUAGUA, UAGUCAGGCUAAGUAGUA, UAGUCAGUAGGCUAAGUA, UAGUAGGCUAAGUCAGUA, UAGGCUAAGUAGUCAGUA, UAGUAGUCAGGCUAAGUA AG AAG AAGU 2. (a) [BB] The last letter in the chain is U, C, G, or A. If it is U or C, the last G-fragment will be abnormal. If it is G, the last U,C-fragment will be abnormal. If it is A, the last G and the last U,C-fragments will each be abnormal. (b) [BB] There are two abnormal fragments if and only if the chain ends with A. 3. [BB] The chains GGUGU and GUGGU have the same G- and U,C-fragments. We leave it to you to check that no shorter chains exist. 4. (a) [BB] An abnormal fragment must have arisen from the use of either a G-enzyme or a U,C-enzyme. But a G-enzyme cuts after each G, so an
This is the end of the preview. Sign up
access the rest of the document.