题目

For or Against?—That Is the QuestionAndy is the most unreasonable and he makes me so angry that I could even scream sometimes! Of course, I sort of have to love him because he is my twin brother. Andy and Amy （that is me） have the same curly hair and dark eyes and are equally stubborn. Yet, on most issues we usually take opposite positions.Just this week in our school, there was a heated discussion on whether to adopt a school dress code. Every student would be required to wear a uniform. The teachers are divided: Some are in favor of the uniforms while others are opposed. The principal （8分）某致病细菌分泌的外毒素，无色，细针状结晶，对小鼠和人体有很强的毒性，可引起流涎、呕吐、便血、痉挛等，以致死亡。该外毒素为环状肽，结构式如下图所示。请据图分析并回答问题。(1)该化合物中含有游离的________个氨基，________个羧基。       (2)该化合物是由________个氨基酸组成的。(3)组成该化合物的氨基酸有________种(4)填写虚线框内结构的名称：A.________，B.________(从氨基酸结构通式的角度分析)。(5)该外毒素在环状肽形成过程中失去了________个水分子，相对分子质量减少了________。