An Experiment Is Performed in Which a Point Mutation Is $\zeta$

question 10

Multiple Choice

An experiment is performed in which a point mutation is introduced randomly into the Zap-70 gene for a particular strain of mice.The mutant mice display a defect in T cell development.However,precursor T cells isolated from the thymus of these mice show normal expression levels of Zap-70 of the correct molecular weight.On further in vitro analysis,the mutant Zap-70 is found to bind to ITAM motifs in the cytoplasmic tail of the $\zeta$ chain,but only when the $\zeta$ chain is phosphorylated.No phosphorylated LAT is detected,however.Given these data,in which of the following protein domains is the mutation most likely to be present?

• A)Pleckstrin homology (PH)domain
• B)Proline-rich (PR)domain
• C)SH1 domain
• D)SH2 domain
• E)SH3 domain

---

Definitions:

Stockholders' Equity

The residual interest in the assets of a corporation after deducting its liabilities.

Trading Securities

Financial assets that a firm holds primarily for the purpose of selling them in the short term to profit from price fluctuations.

Adjusting Entries

Entries made at the end of an accounting period to ensure that companies follow the revenue recognition and expense recognition principles.

Fair Value

An estimate of the market value of an asset or liability, based on current conditions and willing parties' transactions.