1In the T7lac expression system used for ADH expression whic

1.In the T7/lac expression system used for ADH expression, which of the following is true?

The promoter for the ADH gene is specific for E. coli RNA polymerase.

The promoter for the ADH gene contains the lac operator sequence.

The pLacI plasmid encodes the T7 RNA polymerase gene.

All of the above

2.The ADH gene used in this lab contains

A his-tag at the N-terminus

An HSV tag near the N-terminus

A strep tag at the C-terminus

None of the above

3.During ADH expression in Tuner cells, which of the following occurs?

Binding of IPTG to the Lac repressor protein facilitates expression of the T7 RNA polymerase.

IPTG represses the expression of the Lac repressor protein.

The presence of glucose in the medium results in CAP-binding protein recruiting E. coli RNA polymerase to the T7 RNA polymerase gene.

All of the above

4. How would you interpret your NovaBlue transformation results if you saw no colonies on any of your plates (controls and experimental)?

You used the wrong cells for the transformation.

You used the wrong medium for the transformation.

You heat shocked the cells for too long.

Any of the above could explain the results.

5.In SDS-PAGE, which of the following is true?

The proteins are only negatively charged in the resolving gel.

The stacking gel has a higher pH than that of the resolving gel.

The concentration of acrylamide is higher in the stacking gel relative to the resolving gel.

none of the above

Solution

1.The correct answer is:The promoter for the ADH gene contains the lac operator sequence.

Reason:The above statement is true.Other two are false.The promoter for the ADH gene is specific forT7 bacteriophage RNA polymerase.The pLacI plasmid encodes the T7 RNA polymerase gene.The pLacI plasmid encodes the lac repressor protein.

2.The correct answer is:none of the above

Reason: No tags are present in ADH gene.

3.The correct answer is:Binding of IPTG to the Lac repressor protein facilitates expression of the T7 RNA polymerase.

Reason:Binding of IPTG to the Lac repressor protein prevents it binding to operator and this results in expression of T7 RNA polymerase.

4.The correct answer is:You heat shocked the cells for too long.

Reason:Longer periods of heat can effect transformation efficiency of cells.

5.The correct answer is:none of the above.

Reason: Proteins are negatively charged through out the gel.Stacking gel is 2 pH units less than resolving gel and the acrymalide concentration in stacking gel is less than resolving gel.