Seek the knowledge points of compulsory 2 in senior high school biology,
2
Chapter 1 Section 1
1. Mendel discovered the law of biological inheritance by analyzing the results of pea hybridization experiment.
2. When Mendel did the hybridization experiment, he first removed all the stamens of the immature flowers, which is called emasculation.
3. The different expression types of the same trait of an organism are called relative traits.
4. Mendel called the traits that F1 showed as dominant traits, and the traits that did not show as recessive traits. In hybrid offspring, the phenomenon that both dominant traits and recessive traits appear at the same time is called trait separation.
5. Mendel put forward the following hypotheses about the causes of segregation:
(1) The traits of organisms are determined by genetic factors, in which the dominant genetic factors determine the apparent traits, which are represented by capital letters, and the recessive genetic factors determine the recessive traits, which are represented by lowercase letters.
(2) Genetic factors in somatic cells exist in pairs. Individuals with the same genetic factors are called homozygotes, while individuals with different genetic factors are called heterozygotes.
(3) When an organism forms a germ cell-gamete, the paired genetic factors are separated from each other and enter into different gametes, and each gamete contains only one genetic factor of each pair.
(4) During fertilization, the combination of male and female gametes is random.
6. Test crossing is to cross F1 with recessive homozygote.
7. Mendel's first law is also called separation phenomenon. In the somatic cells of organisms, the genetic factors controlling the same trait exist in pairs and do not fuse. When gametes are formed, the paired genetic factors are separated, and the separated genetic factors enter different gametes and are passed on to future generations with gametes.
Chapter 1, Section 2
1. Mendel crossed pure yellow round pea and pure green wrinkled pea as parents, and the seeds (F1) were yellow round, regardless of cross or cross. This shows that yellow and round grains are dominant traits, while green and wrinkled grains are recessive traits.
2. Mendel selfed the F1 with yellow round grains, and found yellow round grains and green wrinkled grains in the F2, as well as the combination of green round grains and yellow wrinkled grains that the parents did not have.
3. The genetic factors of pure yellow round pea and pure green wrinkled pea are yyrr and YyRr, respectively, and the F1 genetic factors produced by them are YYRR, showing yellow round pea.
4. In Mendel's hybridization experiment of two pairs of relative traits, when F1(YyRr) produced gametes, each pair of genetic factors was separated from each other, and different pairs of genetic factors could be freely combined. There are four kinds of female gametes and four kinds of male gametes produced by F1: Yr, yR, YR, and the quantitative ratio is 1: 1: 1: 1. During fertilization, the combination of male and female gametes is random. There are 16 ways to combine female and male gametes, and there are 9 ways to combine genetic factors: YYRr, YYYrr, YyRR, YyRr, Yyrr, YYYRR, YYRR, YYRR. There are four kinds of characters: yellow round grain, yellow wrinkled grain, green round grain and green wrinkled grain, and the quantitative ratio between them is 9: 3: 3: 1.
5. When F1(YyRr) is crossed with recessive homozygote (yyrr), whether F1 is the female parent or the male parent, there are four phenotypes of offspring: yellow round grain, yellow wrinkled grain, green round grain and green wrinkled grain, the ratio between them is 9: 3: 3: 1, and there are nine combinations of genetic factors: YYRr and YYYR.
6. Mendel's second law is also called the law of free combination. The separation and combination of genetic factors that control different traits do not interfere with each other. When forming gametes, the genetic factors that determine the same trait are separated from each other, and the genetic factors that determine different traits are freely combined.
in 199, Danish biologist Johnson named Mendel's "genetic factor" gene, and put forward the concepts of phenotype and genotype.
8. Phenotype refers to the traits displayed by individual organisms, the genes controlling relative traits are called alleles, and the gene composition related to phenotype is called genotype.
chapter 2, section 1
1. meiosis is the cell division in which the number of chromosomes is halved when sexually reproducing organisms produce mature germ cells. In the process of meiosis, chromosomes are copied only once, while cells divide twice. As a result of meiosis, the number of chromosomes in mature germ cells is reduced by half compared with that in original germ cells.
2. Spermatogonial cells are primitive male germ cells, and the number of chromosomes in each somatic cell is the same as that in somatic cells.
3. During the first meiotic division, the volume of spermatogonia increases, and chromosomes replicate and become primary spermatocytes. After replication, each chromosome consists of two sister chromatids, which are connected by the same centromere.
4. Paired chromosomes are generally the same in shape and size. One is from the father and the other is from the mother, which is called homologous chromosome. The phenomenon that homologous chromosomes are paired in pairs is called synapse.
5. Each pair of homologous chromosomes after synapsis contains four chromatids, which are called tetrads.
6. The paired homologous chromosomes are separated from each other and move to the two poles of the cell respectively during the first meiotic division.
7. In the process of meiosis, half of chromosomes occur in the first meiosis.
8. When the centromere of each chromosome divides, the two sister chromosomes also separate and become two chromosomes during the second meiotic division.
9. Two secondary spermatocytes formed in the first meiotic division, after the second meiotic division, formed four spermatocytes. Compared with the primary spermatocytes, each spermatocyte contains half the number of chromosomes.
1. The primary oocyte undergoes meiosis for the first time to form two cells with different sizes, the large one is called the secondary oocyte, and the small one is called the polar body. The secondary oocyte undergoes secondary division to form a large oocyte and a small polar body, so a primary oocyte undergoes meiosis to form an egg and three polar bodies.
11. Fertilization is a process in which eggs and sperm recognize each other and fuse into fertilized eggs.
12. After fertilization, the number of chromosomes in fertilized eggs is restored to that in somatic cells, half of which are from sperm (paternal side) and the other half from egg cells (maternal side).
Chapter II Section II
1. There is an obvious parallel relationship between genes and chromosome behavior.
(1) Genes maintain integrity and independence during hybridization, and chromosomes also have relatively stable morphological structures during gamete formation and fertilization.
(2) Genes exist in pairs in somatic cells, so do chromosomes. There is only one gene in a gamete, and there is also only one chromosome.
(3) The paired genes in somatic cells are one from the father and one from the mother, and so are homologous chromosomes.
2. There are many pairs of chromosomes in a somatic cell of Drosophila melanogaster, among which 3 pairs are autosomes and 1 pair is sex chromosomes. A pair of sex chromosomes of male Drosophila melanogaster is heteromorphic, denoted by XY, and a pair of sex chromosomes of female Drosophila melanogaster is homotypic, denoted by XX.
3. The genotype of male Drosophila melanogaster with red eyes is XwY, that of female Drosophila melanogaster with red eyes is XWXw /XWXW, that of male Drosophila melanogaster with white eyes is XWY, and that of female Drosophila melanogaster with white eyes is XWW.
4. American biologist Morgan and his students, after more than ten years' efforts, found a method to explain the relative position of genes on chromosomes, and drew the first relative position map of various genes in Drosophila, indicating that genes are linearly arranged on chromosomes.
5. The essence of gene separation phenomenon is that in heterozygous cells, alleles located on a pair of homologous chromosomes have certain independence. In the process of dividing into gametes, alleles will separate with the separation of homologous chromosomes, enter into two gametes respectively, and be passed on to offspring independently with the gametes.
6. The essence of the law of free combination of genes is that the separation or combination of non-allelic genes located on non-homologous chromosomes does not interfere with each other. During meiosis, while the alleles on homologous chromosomes are separated from each other, the non-allelic genes on non-homologous chromosomes are free to combine.
Chapter II Section III
1. Traits controlled by genes located on sex chromosomes are always genetically related to sex, which is called sex-linked inheritance.
2. Genetic characteristics of recessive inheritance with X:
(1) Recessive pathogenic genes and their alleles are only located on the X chromosome.
(2) There are more male patients than female patients.
(3) There is often atavism phenomenon.
(4) The son of a female patient must be ill. (The mother will be ill) < P > 3. Genetic characteristics with X dominant inheritance:
(1) Dominant pathogenic genes and their alleles are only located on the X chromosome.
(2) There are more female patients than male patients.
(3) It has the continuity of generations.
(4) The daughter of a male patient must be ill. (If the father is ill, the woman will be ill)
4. In the diagram representing a family, the square usually represents the male, the circle represents the female, the Roman numerals represent the generations (such as I and II), and the Arabic numerals represent the individuals (such as 1 and 2).
5. The human X chromosome and Y chromosome are different in size and the kinds of genes they carry. The X chromosome carries many genes, while the Y chromosome is only about 1/5 of the size of the X chromosome and carries fewer genes.
Chapter III Section 1
1. Chromosomes are composed of DNA and protein, among which DNA is the embodiment of all life phenomena. It has important continuity in mitosis, fertilization and meiosis.
2. The evidence that DNA is genetic material is the transformation experiment of pneumococcus and the infection of bacteria test by phage.
3. Transformation test of pneumococcus:
(1) Experimental purpose: to prove what genetic material is.
(2) experimental materials: S-type bacteria and R-type bacteria.
bacterial colony toxicity
The surface of S-type bacteria is smooth with capsule
The surface of R-type bacteria is rough without capsule
(3) Process: ① Mice do not die when R-type live bacteria are injected into mice.
② The mice died when S-type live bacteria were injected into mice.
③ The killed S-type bacteria were injected into mice, and the mice did not die.
④ non-toxic R-type bacteria were mixed with S-type bacteria killed by heat and injected into mice, and the mice died.
⑤ DNA, protein and polysaccharide were extracted from S-type living bacteria and cultured in R-type living bacteria respectively. It was found that only by adding DNA could R-type bacteria be transformed into S-type bacteria.
(4) Analysis of results: ①→④ The process proved that the S-type bacteria killed by heating contained a "transformation factor"; ⑤ The process proves that the transformation factor is DNA.
conclusion: DNA is genetic material.
4. Experiment of bacteriophage infecting bacteria:
(1) Objective: Is the genetic material of bacteriophage DNA or protein?
(2) experimental material: phage.
(3) process: ① protein of T2 phage was labeled by 35S, infecting bacteria.
② DNA in T2 phage was labeled with 32P, which infected bacteria.
(4) Analysis of results: The test results showed that only DNA entered the bacteria during the infection process, but not after 35S, indicating that only the DNA of the parent phage entered the cells. The various characters of the progeny phage are inherited through the DNA of the parents. DNA is the real genetic material.
5. Evidence that RNA is genetic material:
(1) protein extracted from tobacco mosaic virus cannot infect tobacco.
(2) Extracting RNA from tobacco mosaic virus can infect tobacco.
6. Conclusion: The genetic material of most organisms is DNA, and DNA is the main genetic material. The genetic material of very few viruses is not DNA, but RNA.
chapter 3, section 2
1. DNA is a polymer compound, and each molecule is a long chain formed by the polymerization of hundreds of four kinds of deoxynucleotides.
2. structural features: ① double helix structure consisting of two deoxynucleotide chains spiraling in reverse parallel.
② outside: the basic skeleton is composed of deoxyribose and phosphoric acid alternately connected.
③ inside: the bases on the two chains are connected by hydrogen bonds to form base pairs. The form of base pair follows the principle of base complementary pairing, that is, A must be paired with T (there are two hydrogen bonds) and G must be paired with C (there are three hydrogen bonds).
3. The amount of adenine (a) in double-stranded DNA is always equal to the amount of thymine (t). The amount of guanine (g) is always equal to the amount of cytosine (c).
Chapter III, Section III
1. The concept of DNA replication: it is the process of synthesizing progeny DNA using parent DNA as a template.
2. Time: DNA molecular replication is completed with chromosome replication during the interval of cell mitosis and the first meiosis.
3. location: nucleus.
4. process:
(1) unwinding: DNA first uses the energy provided by mitochondria to untie the double-stranded two helices under the action of helicase.
(2) Synthesis of sub-chains: Using each untied mother chain as a template and four kinds of free deoxynucleotides as raw materials, following the principle of base complementary pairing, and under the action of related enzymes, the sub-chains complementary to the mother chain are synthesized respectively.
(3) Formation of daughter DNA: each daughter strand and its corresponding template spiral into a double helix structure, thus forming two daughter DNAs which are completely identical to the parent DNA.
5. Features:
(1)DNA replication is a process of unwinding and copying.
(2) Because all newly synthesized DNA molecules retain a strand of the original DNA, this replication is called semiconservative replication.
6. conditions: the template needed for DNA molecular replication is DNA mother chain, and the raw material is free deoxynucleic acid, which requires energy ATP and presence.