BIOL202 lac operon worksheet PDF

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BIOL 202 Recitation Week 6: Lac Operon Worksheet Name: 1) Which genotype results in constitutive expression of the Z gene? a. I+ OC Z- Y+ b. I+ OC Z+ Y+ c. IS O+ Z+ Y+ d. I+ O+ Z+ Y+ 2) The tryptophan operon with its repressor is

a. b. c. d.

Positively regulated Negatively regulated Inducible Constitutive

3) If the Y gene is uninducible will it be expressed when lactose is present? a. Yes b. No 4) The genotype I- O+ Z+ Y+ is a. Inducible b. Uninducible c. Constitutive 5) How are Z and Y expressed for: cap- I+ O+ Z- Y+ / cap- I- O+ Z+ Y-? a. Z constitutively, Y inducible b. Z inducible, Y inducible c. Z uninducible, Y constitutively d. Z uninducible, Y uninducible 6) How are Z and Y expressed for: I+ O+ Z+ Y+ / I- O+ Z+ Y+? a. Z constitutively, Y inducible b. Z inducible, Y inducible c. Z uninducible, Y constitutively d. Z uninducible, Y uninducible

BIOL 202 Recitation Week 6: Lac Operon Worksheet Name: 7) Which of these leads to an inducible Z gene and an uninducible Y gene? a. I+ O+ Z- Y+ b. I+ OC Z+ Yc. I+ O+ Z+ Yd. I- O+ Z+ Y8) Here is the result of a northern blot. What do these bands represent?

a. b. c. d.

The visualization of DNA The visualization of protein The visualization of tRNA The visualization of mRNA

9) How are Z and Y expressed for: I+ OC Z- Y+ / IS O+ Z+ Y+ ? a. Z inducible, Y inducible b. Z constitutive, Y constitutive c. Z uninducible, Y constitutive d. Z uninducible, Y uninducible 10) Which genotype has an uninducible Z gene and an uninducible Y gene? a. I+ O+ Z- Y+ b. I+ OC Z+ Yc. IS O+ Z+ Y+ d. IS OC Z+ Y+ 11) You design your probe to mark the estrogen+ gene. What is your negative control?

a. b. c. d.

A sample of tissue I know for a fact is estrogen+. A sample of tissue I know for a fact is estrogen-. The sample tissue tested with a probe that marks estrogen-. The sample tissue tested with a probe that marks estrogen+.

BIOL 202 Recitation Week 6: Lac Operon Worksheet Name: 12) When glucose is high/present cAMP is a. Low b. High c. cAMP doesn’t depend on glucose 13) The lac operon is a. Positively regulated b. Negatively regulated c. Neither d. Both 14) True or False: RNA polymerase is a regulatory trans factor? a. True b. False 15) Is the Y gene expressed for the following genotypes: IS O+ Z+ Y+ / I- O+ Z+ Y+ a. Yes b. No 16) True or False: The lac operon and trp operon repressors are both innately active (default = bind to operator) a. True b. False 17) Mutations in trans factors are always a. Constitutive b. Uninducible c. Both d. Neither 18) Which is the coding strand?

a. b. c. d.

Top strand Bottom strand Both Neither

BIOL 202 Recitation Week 6: Lac Operon Worksheet Name: 19) True or false: Cis elements can affect the expression of genes on a different chromosome a. True b. False 20) If an anti codon is 3’ UCU 5’ which amino acid does it hold?

a. b. c. d.

Ser Arg Thr Glu

21) The inducer for the lac operon is a. Lactose b. Beta-galactosidase c. cAMP d. CAP 22) A mutation in the repressor prevents it from binding to the operator. What will occur? a. Continuous transcription of operon genes b. Reduced transcription of operon genes c. Irreversible binding of the repressor to the promotor d. Overproduction of CAP...