Answer to Question 1
ANS: C
Alkylating agents replace a hydrogen atom with an alkyl group. The irreversible combination of alkyl groups with nucleotide chains, particularly deoxyribonucleic acid (DNA), causes unbalanced growth of unaffected cell constituents so that the cell eventually dies. Plant alkaloids arrest the cell in metaphase by binding to proteins needed for spindle formation. Antimetabolites resemble essential metabolic elements needed for growth but are different enough to block further DNA synthesis. Antitumor antibiotics are natural substances that interfere with cell division by reacting with DNA in such a way as to prevent further replication of DNA and transcription of ribonucleic acid (RNA).
Answer to Question 2
ANS: C
Chemotherapeutic agents are classified according to mechanism of action. For example, antimetabolites resemble essential metabolic elements needed for growth but are different enough to block further deoxyribonucleic acid (DNA) synthesis. Although the side effect profiles may be similar for drugs within a classification, they are not the basis for classification. Most chemotherapeutic regimens contain combinations of drugs. The effectiveness of any one drug is relative to the cancer type, combination therapy, and protocol for administration. The route of administration is determined by the pharmacodynamics and pharmacokinetics of each drug.
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