The Table Below Lists Several Genotypes Associated with the Lac $\beta$

question 56

Essay

The table below lists several genotypes associated with the lac operon in E.coli.For each,indicate with a "+" or a "-" whether functional $\beta$ -galactosidase would be expected to be produced at induced levels.
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { B-Galactosidase Production }$
$\begin{array}{lccc}\text { Genotype }& \text { No Lactose } &\text { With Lactose } \\\hline \text { (a) } I+O+Z+/ F^{\prime} I-O+Z+\\\text { (b) } I-O c Z+/ F^{\prime} I-O+Z-\\\text { (c) Is Oc Z+/ } F^{\prime} I+O+Z+\\\text { (d) } I-O+Z+/ F^{\prime} I-O+Z+\\\end{array}$

$I^{+}=$ wild-type repressor
$I$ - = mutant repressor (unable to bind to the operator)
$\mathrm{I}^{s}=$ mutant repressor (insensitive to lactose)
$\mathrm{O}^{+}=$ wild-type operator
$\mathrm{O}^{c}=$ constitutive operator (insensitive to repressor)

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Definitions:

Economies of Scale

The cost advantages that enterprises obtain due to their scale of operation, leading to a decreased cost per unit.

Pin Factory

An example used by Adam Smith to describe the benefits of specialization and division of labor in manufacturing, increasing productivity and efficiency.

Constant Returns to Scale

A situation in production where increasing the amount of inputs results in a proportional increase in the output.

Long-run Total Costs

The aggregate expenses a firm incurs in the production of goods or services when all factors of production are variable.