This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: phosphorylation and dephophorylation. TRUE d) The polyadenine tail of mRNA molecules is added because genes end with a stretch of few hundred thymines. FALSE 3. The following diagrams depict three stages in the functioning of the lac operon. State what should be the levels of lactose and glucose in the media in order to observe each stage. (2 points each) A= glucose present; NO lactose; B= glucose present, lactose present; C= NO glucose, lactose present 4. Fill in the blanks (2 points each): a) In splicing, the first transesterification reaction involves the 5' end of the intron and the branch site A of the intron forming a lariat. In the second transesterification the phosphodiester bond between the intron and exon 2 is cut by the free OH at the 3' end of exon 1 thereby releasing the intron and ligating the two exons. The molecular machine (spliceosome) helping this process is a complex of proteins and snRNA's . ( a diagram is presented below.)...
View Full Document