Exam 4 Review & Notes

There are two levels of control of the trp operon

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: binants with mutants # 1, # 3 and #4, but not with mutants #2. Which region does the point muta8on lie in? This ques8on is basically asking you if 1, 3 and 4 contain a muta8on in their DNA, and number 2 does not, where must this muta8on be? Given that 1,3 and 4 all share A, but number 2 does not, suggests that A must be where this muta8on lies. 23. On the discon8nuously replicated DNA strand, dNTPs are added to the: a) 2’ b) 3’ c) 5’ d) Triphosphate e) Monophosphate 23. On the discon8nuously replicated DNA strand, dNTPs are added to the: a) 2’ b) 3’ c) 5’ d) Triphosphate e) Monophosphate dNTPSs are always added to the 3’ end whether a strand is leading or lagging, given that DNA replica8on always occurs in the 5’- 3’ direc8on. 24. The primer used for DNA synthesis is: a) DNA. b) RNA. c) Protein. d) dNTP. e) ddNTP. 24. The primer used for DNA synthesis is: a) DNA. b) RNA. c) Protein. d) dNTP. e) ddNTP. DNA polymerases cannot start a new DNA chain from scratch. They can only ahach new nucleo8des onto 3' OH group of a nucleo8de in a preexis8ng strand. Therefore, to start the synthesis of the leading strand, as well as each DNA fragment of the lagging strand, an RNA primer is necessary. Straight from page 121 of the lecture notes, talking about the discon8nuous strand: “DNA is synthesized in the same direc8on as the fork moves. But the 5' to 3' template strand must be copied in short spurts going away from the replica8on fork. This requires the repeated restart of synthesis, something that DNA polymerase III can not do. The enzyme that carries out this restart process is DNA primase, and it makes an RNA molecule, not a DNA molecule.” 25. The purpose of bacterial host restric8on/modifica8on systems is to: a) Replicate DNA. b) Methylate DNA bases. c) Mutagenize DNA. d) Prevent phage infec8on. e) Promote phage infec8on. 25. The purpose of bacterial host restric8on/modifica8on systems is to: a) Replicate DNA. b) Methylate DNA bases. c) Mutagenize DNA. d) Prevent phage infec3on. e) Promote phage infec8on. Straight from page 148 of Dr. Zitomer’s lecture notes: “Around 1970, researchers studying the crude immunity system of bacterial cells discovered host restric8on- modifica8on systems. These systems allowed bacterial cells to combat the spread of phage through a species by recognizing the difference between host and foreign DNA.” 26. Transcrip8on results in: a) A DNA molecule. b) An RNA molecule. c) A...
View Full Document

Ask a homework question - tutors are online