In an Experiment, Erythrocyte Precursor Cells Are Incubated in a Medium

question 68

Multiple Choice

In an experiment, erythrocyte precursor cells are incubated in a medium containing radiolabeled cysteine.  These radiolabeled cysteine residues are attached to their appropriate tRNAs by the enzyme aminoacyl-tRNA synthetase.  The bound cysteine residues are then chemically modified to form alanine.  The end product of this reaction is a tRNA molecule that contains the cysteine anticodon but is mischarged with alanine.  Which of the following is most likely to occur to this alanine residue during polypeptide synthesis of alpha-hemoglobin?

• A)It will be incorporated into the polypeptide chain at a site requiring alanine
• B)It will be incorporated into the polypeptide chain at a site requiring cysteine
• C)It will be randomly incorporated into the polypeptide chain, halting chain elongation
• D)It will be rapidly cleaved off tRNA by the enzyme glycosylase
• E)It will never be incorporated into the polypeptide chain and will remain attached to tRNA

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Definitions:

Net Operating Income

This refers to a company's income after operating expenses are deducted, but before interest and taxes are subtracted.

Grinding Minutes

The amount of time spent on grinding operations in the manufacturing process, often used as a measure of labor or machine use.

Variable Manufacturing Overhead

Costs in manufacturing that vary with operational output, such as indirect materials, utilities, and other expenses that increase with production volume.

Fixed Manufacturing Overhead

Regular, consistent costs associated with operating a manufacturing facility that do not vary with the level of production, such as salaries and rent.