Molecular Biology exam 1 for 60 points
1. Define Molecular Biology (0.5 pt)
2. Molecular Biology is a combination of ____________________ and
_____________________ (1 pt)
3. What is Transmission Genetics? (1 pt)
4. On any chromosome, different genes are located in their respective region known as
__________________ (0.5 pt)
5. What is the main difference between phenotype and genotype of an individual? (0.5 pt)
6. The result of crossing over is _____________________. What does this process result
in? (0.5 pt)
7. How do genes accumulate mutations? (1 pt)
8. What are the two steps involved in gene expression of any polypeptide? (1 pt)
9. ___________________________ bacteria were used in transformation experiment by
Griffith (0.5 pt)
10. Ratio of G to C and A to R are fixed in any specific organism – True/False (0.5 pt)
11. Temperature at which DNA strands are ½ denatured is known as
_______________________ (0.5 pt)
11. How did Griffith perform his ‘transformation expt’? How differently did three other
scientists in 1944 (name them along with description of their work) test Griffith’s
transformation expt’? (4 pts)
12. Name any three different factors and their role in denaturing DNA (2 pts).
13. GC content does not affect DNA density – True/False (0.5 pt)
14. What is renaturation? Name three factors playing a role in DNA renaturation. (2 pts)
15. What is C value? What is C-value paradox? (2 pts)
16. What is the difference between motif and domain (1 pt).
17. Mention a few differences between transcription and replication (1 pt)
18. ________________ kind of ribosome is found in prokaryotes (0.5 pt)
a) 70 S b) 80S c) both a and b d) 50S
19. Anticodon is present in (0.5 pt)
a) mRNA b) tRNA c) both a and b d) DNA
20. Enzyme that catalyzes attachment of aminoacid to tRNA is ____________________
(0.5 pt)
21. Shine Dalgarno is found in (0.5 pt)
a) Prokaryotes b) Eukaryotes c) both a and b d) none
22. mRNA has 5’ leader and 3’ ________________ sequences (0.5 pt).
a) 3’ UTR b) 5’UTR c) 5’ trailer d) 3’ trailer e) both a and d
23. _________________ is DNA carrier that allows replication of recombinant DNAs.
What is the difference between phage and plasmid? (2 pts)
24. What are the three possible results of transformation of recombinant DNA plasmid
into a bacterium? (1.5 pts)
25. Using two restriction enzymes provides directional cloning – True/False (0.5 pt)
26. Phage vectors can receive larger amounts of foreign DNA – True/False (0.5 pt)
27. What is the difference between genomic and cDNA cloning or library? (2 pts)
28. What is the difference between cloning and expression vectors? (2 pts)
29. Name some problems that a scientist has to face while working with bacterial
expression systems.(1.5 pts)
30. What are the different subunits of RNA polymerase? Name the subunit that plays a
role in the assembly of whole RNA polymerase. (1 pt)
31. What is the difference between core and holoenzymes? (1 pt)
32. _____________ subunit of RNA polymerase recognizes promoter region of DNA.
(0.5 pt)
33. What are the three core promoter elements? (0.5 pt)
a. TSS, -10 and -35 regions b. TSS, -10 and UP c. -10, -35 and UP d. TSS, -10, -35
regions and UP
34. Polymerase causes a separation of about _________ DNA base pairs (1 pt)
a. 10 bp b. 12bp c. 17 – 18 bp d. all the above have been obtained as results in different
experiments
35. How many regions is subunit σ divided into? (1 pt)
a. 4 b. 3 c. 2 d. each region is subdivided into 2 or more
36. ____________ region of subunit σ recognizes -10 box of promoter (0.5 pt).
37. ____________ region of subunit σ recognizes – 35 element of promoter (0.5 pt).
.
38. Name the two types of terminator mechanisms present in prokaryotes (1 pt)
39. _____________ subunit of RNA polymerase recognizes UP element of DNA. (0.5 pt)
40. Define operon (1 pt).
41. All three operators are required for optimum repression in ___________ operon
a. lac b. ara c. trp d. all the above (0.5 pt)
42. One theory states that repressor binding to operator prevents RNA polymerase from
binding to the promoter. What is the other theory? (1 pt)
43. Why do bacteria use operon system for its gene expression and regulation? (1 pt)
44. The breakdown product of glucose is ________ (0.5 pt)
a. AMP b. allolactose c. lactose d. sugar
45. Positive controller of lac operon has 2 parts: _____________ and
__________________ (1 pt)
46. The binding of CAP-CMP dimer does ________________ (0.5 pt)
a. recruits RNA polymerase
b. allows binding of RNA polymerase to DNA
c. forms closed promoter complex
d. all the above are true statements
47. ___________________ sugar acts as positive and negative regulator in ara operon
a. Arabinose b. Lactose c. Tryptophan d. Allolactose ( 1 pt)
48. DNA looping present in ara operon is _______________ operon (1 pt)
a. Repressing b. turning off c. turning on d. positive control e. both a and b
49. The trp operator lies wholly within the trp promoter – True/False (0.5 pt)
50. What factors turn on and off the lac operon? (2 pts)
51. What factors turn on and off the trp operon? (2 pts)
52. Attenuation is characteristic feature of ______ operon. (1 pt)
a. lac b. ara c. trp d. all the above
53. Attenuation operates in the E. coli trp operon as long as tryptophan is plentiful –
True/False (1 pt)
54. RNA polymerase I is found in _____________ part of cell. (1 pt)
a. Nucleolus b. Nucleoplasm c. Cytoplasm d. throughout the cell
55. RNA polymerase II and III are found in _____________ part of cell.(1 pt)
a. Nucleolus b. Nucleoplasm c. Cytoplasm d. throughout the cell
56. ______________ polymerase transcribes rRNA (0.5 pt)
57. ______________ polymerase transcribes tRNA (0.5 pt)
58. _____________ is total number of subunits of RNA polymerase in eukaryotes.
a. 10 b. 12 c. 9 d. 15 (1 pt)
59. What is the structure and shape of RNA polymerase in eukaryotes? How does it
interact with DNA (1 pt)
60. Among the three critical elements involved in transcription (lid, rudder and zipper),
which one dissociates the DNA template? (1 pt)
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