Molecular Biology Exam 2 Mar 9, 2012 Name:
PLEASE WRITE LEGIBLY. IF THE GRADER CANNOT READ YOUR ANSWER IT WILL BE MARKED WRONG.
1-20. Multiple choice. (20pts/ 1 pt each). Enter the letter of choice that best answers question in the space
provided. (circled sentences will NOT receive credit)
1. A.
2. C.
3 a.
4.d
5.a.
6. a.
7 a.
8 b.
9. a.
10 b.
11. a.
12. d.
13. c.
14. c.
15.d.
16. b.
17 c.
18. a.
19. b.
20. b.
21-30. For each of the following statements, indicate whether the statement is true or false. If the statement is true,
explain. If a statement is false, correct the statement or explain why it is false (2pts each)
correct answer of true with no details – ½ credit
21. TRUE -- a significant distinguishing feature. Euk RNA polymerase must be recruited by transcription factors-
cannot bind promoter on its own / Bacterial RNA pol holoenzyme contains sigma factor
22. False – bacterial mRNA is unstable – typical half life less then 5 min// euk mRNA range in stability but on
average much more stable than bacterial – longer take more time to synthesize/ need to transport to cyto for
translation
23. FALSE: TBP is the positioning factor for transcription initiation by all eukaryotic RNA polymerases – I, II and
III
24 TRUE chromatin remodeling loosens association with histones/ remove histone leading to inc sens
25 TRUE – removal of poly A and cap are steps in the degradation of euk mRNA
Cap protects against 5’ to 3’ exo nuc / poly A protects from 3’ to 5’ exonuclease
26 True – Rho is prokaryotic termination protein . It has ATPase and helicase activities
binds to RNA at rut site and Rho tracks along RNA and when RNA pol pauses at termination helicase activity unwinds
RNA-DNA hybrid to cause termination
27 FALSE – transcription and translation similar 40-45nt/s and 15aa/s (important for some regulatory events)
Transcription is much slower than replication 40 nt /s vs 800bp/s (Rep)
1
