REGULATION OF THE GENE EXPRESSION 2 Flashcards Preview

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Flashcards in REGULATION OF THE GENE EXPRESSION 2 Deck (8)
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1
Q

Mutations in the LacZ or LacY genes result in?

A

in a loss of either (but not both) activities, and these mutations were recessive

  • Thus, loss of the genes encoding either enzyme results in a lack of the respective activity- LacZ and
  • LacY are structural genes that encode the amino acid sequence of the respective enzymes
2
Q

A recessive mutation in a linked gene, LacI, resulted in?

A

high levels of LacZ and LacY even in the absence of inducer (i. e. constitutive expression).

3
Q

What two different kinds of elements are present in the lac operon’s regulation?

A

DNA binding sites (LacP, LacO, Pi),

Proteins (CAP, LacI, and LacZ, LacY, and LacA).

4
Q

Cis dominant mutations in the Lac operator resulted in?

A

constitutive high level expression of both LacZ and LacY.

5
Q

Cis dominant mutations in the lactose promoter result in

A

a lack of expression of both the LacZ and LacY genes.

6
Q

Catabolite Activator Protein (CAP) turns?

A

the Lac genes on when glucose is not present.

7
Q

ARABINOSE OPERON

A

is responsible for the ability of the cell to use the sugar arabinose as a carbon source

8
Q

The ara operon is only expressed? (In /When)

A

1) In the presence of the substrate arabinose. and

2) When levels of the preferred carbon source glucose is low.