Molecular Biology Techniques Test 2

What are the necessary inducer to start the transcription in prokaryotes?

• Sigma factor and holoenzyme

• Haloenzyme

• Sigma factor and core enzyme

• RNA polymerase

Arrange the steps for transcription in decreasing order.

• initiation - elongation - termination

• initiation - termination - elongation

• termination - initiation -elongation

• termination - elongation - initiation

All the statement are TRUE about Rho factor EXCEPT

• binds to the transcription terminator pause site

• function by wrapping nucleic acid around the single cleft

• essential transcription protein in prokaryotes

• unwinding the RNA transcript from DNA template in elongation step

What is lac repressor?

• glucose sensor

• start acting as repressor when glucose is present

• block transcription of operon in certain condition

• bind to isomer of allalactose

What is catabolite activator protein?

• lactose sensor

• sense glucose through hunger signal, cAMP

• active the transcription when the glucose is high

• stop the transcription of the operon when the glucose is low

How to start or initiate the lac operon function?

• Glucose is available, lactose not available

• Sucrose not available, pentose is available

• Pentose not available, sucrose is available

• Glucose not available, lactose is available

These are the region of lac operon EXCEPT

• cAMP site

• operator

• promoter

• lacZ, lacY and lacA

When the low level of transcription occur?

• Glucose present, lactose absent

• Glucose absent, lactose absent

• Glucose present, lactose present

• Glucose absent, lactose present

When the strong transcription occur?

• Glucose present, lactose absent

• Glucose present, lactose present

• Glucose absent, lactose absent

• Glucose absent, lactose present

What is the condition that activate CAP?

• cAMP levels are high because glucose is absent

• cAMP levels are low because glucose is absent

• cAMP levels are low because glucose is present

• cAMP levels are high because glucose is present