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生物学试题中,也有一些涉及计算和计数,它可从一个侧面考查学生对生物学原理的理解和掌握程度。我把生物教学中有关计算、计数题分为四类进行分析讨论(以高考题作为例题)。 1.关于核苷酸与碱基的计算核苷酸是构成核酸(DNA和RNA)的基本单位,而每个核昔酸又是由一分子核糖、一分子碱基和一个分子磷酸组成,因此在核酸中核苷酸和碱基的数目是同一的。在DNA中核苷酸或碱基还是成对存在的。例1.(1987年)根据碱基互补配对原则,并且:A≠C,下列四个式子中正确的应该是:
Some of the biological tests involve counting and counting. From one side, it examines students’ understanding and mastery of biological principles. I put the teaching of biology, computing, counting questions divided into four categories for analysis and discussion (college entrance examination questions as an example). 1. Calculation of nucleotides and bases Nucleotides are the basic units that make up nucleic acids (DNA and RNA), and each is composed of one molecule of ribose, one base of a molecule and one molecule of phosphoric acid The number of nucleotides and bases in a nucleic acid is the same. Nucleotides or bases in DNA are still in pairs. Example 1. (1987) According to the principle of complementary base pairing, and: A ≠ C, the following four formulas should be correct: