Which of the Following Statements Explains Why Methotrexate Is Effective

question 25

Multiple Choice

Which of the following statements explains why methotrexate is effective as a cancer chemotherapeutic?

• A) it serves as an analog of p-aminobenzoic acid and block bacterial synthesis of folate
• B) acts as an inhibitor of dihydrofolate reductase, thus preventing production of tetrahydrofolate
• C) it acts as a suicide substrates for the enzyme dihydropteroate synthetase
• D) prevents the conversion of N⁵,N¹⁰-methenyl THF to N¹⁰-formyl THF which is required in 2 steps of the purine synthesis pathway
• E) both b and d are correct

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Definitions:

Discounted Payback

A method to evaluate the profitability of an investment by calculating the time it takes for the net present value of cash flows to equal the initial investment cost.

Required Return

The minimum expected return on an investment necessary to compensate for the risk taken by the investor, including the time value of money and inflation.

Payback

A method of investment appraisal that calculates the time needed for an investment to generate cash flows sufficient to recover the initial outlay.

Four Year Payback

A capital budgeting method that calculates the time required to recoup the initial investment in a project, specifically over a period of four years.