What are the three basic characteristics of genes?

Noun: 1, the principle of base complementary pairing of DNA: A and T pairing, G and C pairing. 2. DNA replication: refers to the process of synthesizing offspring DNA with parent DNA molecules as templates. DNA replication is essentially the replication of genetic information. 3. Unwinding: Under the action of ATP and helicase, the paired bases of two deoxynucleotide chains of DNA molecules are broken from hydrogen bonds. So a part of the double helix is twisted into two parallel double chains, and the two single chains that are untied are called mother chains (template chains). 4. Semi-conservative replication of 4.DNA: Among the progeny double strands, one is the original one of the parents, and the other is newly synthesized. 5. The human genome refers to all the genetic information carried by human DNA molecules. The human genome project is to analyze and determine the nucleotide sequence of the human genome. X0d statement: 1, chemical structure of DNA: ①DNA is a macromolecular compound: its basic elements are C, H, O, N, P, etc. ② It is the basic unit of DNA- deoxynucleotide. Each deoxynucleotide consists of three parts: a deoxyribose, a nitrogenous bases and a phosphoric acid. ③ There are four kinds of deoxynucleotides that make up DNA. Under the action of hydrolase, DNA can get four different kinds. Guanine deoxynucleotide; Cytosine deoxynucleotide; Thymine deoxynucleotide; Deoxyribose and phosphoric acid, which make up four deoxynucleotides, are the same, but the difference is four nitrogenous bases: ATGC. ④DNA is a chain of deoxynucleotides polymerized from four different deoxynucleotides. 2. Double helix structure of DNA: deoxyribose and phosphoric acid are alternately arranged outside to form two main chains (anti-parallel), which constitute the basic skeleton of DNA. The crosspiece between the two main chains is a base pair. Arrange it inside. The two corresponding bases are connected by hydrogen bonds to form a base pair, which determines the base arrangement order on one strand of DNA. According to the principle of base complementary pairing, the base arrangement order of the other chain is also determined. 3. Characteristics of DNA: ① Stability: The alternating arrangement order of deoxyribose and phosphoric acid on two long chains of DNA molecules and the complementary pairing of bases between the two chains are stable. This leads to the stability of DNA molecules. ② Diversity: The sequence of base pairs in DNA is ever-changing. The arrangement of base pairs: 4n(n is the number of base pairs) ③ Specificity: Each specific DNA molecule has a specific base arrangement order, which constitutes the strict specificity of the DNA molecule itself. 4. The application of the principle of base complementary pairing in the calculation of base content: ① In a double-stranded DNA molecule, the sum of two complementary bases is equal, accounting for 50% of the total base of the whole molecule. ② In a double-stranded DNA molecule, the reciprocal of the ratio of the sum of purine and pyrimidine on one chain and the corresponding ratio on its complementary chain. ③ In a double-stranded DNA molecule, the ratio of the sum of two non-complementary bases in one strand (A+T/G+C) is the same as that in the complementary strand and the whole molecule. 5.DNA replication: ① period: the interval between mitosis and the first meiosis; ② Location: mainly in the nucleus; ③ Conditions: a. Template: two mother chains of parental DNA; B, raw materials: four deoxynucleotides are: c, energy: (ATP); D, a series of enzymes. Without any of them, DNA replication cannot be carried out. A. Melting: First, under the action of helicase, DNA molecules use the energy provided by cells to untie two twisted double strands, which is called melting; B, synthesis of sub-chains: then, using each unclosed fragment (mother chain) as a template and deoxynucleotides in the surrounding environment as raw materials, under the action of related enzymes, the sub-chains complementary to the mother chain are synthesized according to the principle of base complementary pairing. With the melting process, the newly synthesized sub-chains continue to extend, and each sub-chain is intertwined with its corresponding parent chain into a spiral structure. C, formation of new DNA molecules. Semi-conservative replication. ⑥ Results: One DNA molecule was copied once to form two identical DNA molecules. ⑥ Meaning: Pass on the genetic information of parents to future generations, so that the previous generations can maintain a certain continuity. ..