Knowledge points of biology in senior high school Chapter 4 Gene expression.
Section 1 Genes Directing protein's Synthesis
I. structure of RNA:
1, component: carbon, hydrogen, oxygen, nitrogen and phosphorus.
2. Basic unit: ribonucleotides (4 kinds)
3. Structure: generally single strand.
Second, genes: DNA fragments with genetic effects. Mainly on chromosomes
Three, gene control protein synthesis:
1, transcription:
Concept (1): According to the principle of base complementary pairing, a strand of DNA is used as a template to synthesize RNA in the nucleus. (Note: Chloroplasts and mitochondria are also transcribed)
(2) Process: ① Unwinding; ② Pairing; 3 contact; ④ release
(3) conditions: template: a DNA chain (template chain)
Raw materials: 4 kinds of nucleotides
Energy: ATP
Enzymes: helicase, RNA polymerase, etc
(4) Principle: base complementary pairing principle (A-U, T-A, G-C, C-G)
(5) products: messenger RNA(mRNA), ribosomal RNA(rRNA) and transport RNA(tRNA)
2. Translation:
Concept of (1): The process of synthesizing protein with a certain amino acid sequence using various amino acids free in cytoplasm as templates. (Note: chloroplasts and mitochondria are also translated)
(2) Process: (Reading)
(3) Conditions:
Template: mRNA
Raw materials: amino acids (20 kinds)
Energy: ATP
Enzymes: various enzymes.
Handling tool: tRNA
Assembly machine: ribosome
(4) Principle: the principle of base complementary pairing.
(5) product: polypeptide chain
3. Calculation related to gene expression
Number of bases of gene: number of bases of mRNA molecule: number of amino acids = 6: 3: 1.
4. Base code
① Concept: Three adjacent bases on mRNA determine 1 amino acid. Every 3 bases is 1 codon.
② Features: specificity, degeneracy and universality.
③ Codon initiation code: Og, GUG(64)
Termination password: UAA, UAG, UGA.
Note: The codon determining amino acid is 6 1, and the stop codon does not encode amino acid.
Gene control of traits in the second quarter
I. Central Rules and Their Development
1, proposed by Crick.
2. Contents:
Second, the way genes control traits:
(1) indirect control: control the metabolic process by controlling the synthesis of enzymes, and then control the biological characteristics; Such as albinism, round grains and wrinkled grains of starch.
(2) Direct control: biological characteristics are directly controlled by controlling protein structure. Such as cystic fibrosis and sickle cell anemia.
Note: polygenic factors of biological traits: genes and genes; Genes and gene products; There are complex interactions between many factors and the environment, and * * * precisely regulates the characteristics of organisms in the same place.
Chapter V Gene Mutations and Other Variations
Section 1 Gene Mutation and Gene Recombination
I. Types of biological variation
Non-genetic variation (only caused by environmental changes)
Genetic variation (caused by changes in genetic material)
Second, genetic variation.
(1) gene mutation
1. Concept: The change of gene structure caused by the substitution, addition and deletion of base pairs in DNA molecules is called gene mutation.
2. Reason:
Physical factors: X-rays, ultraviolet rays, R-rays, etc.
Chemical factors: nitrite, base analogues, etc.
Biological factors: virus, bacteria, etc.
3. Features: A, universality B, randomness C, low frequency D, maximum harmfulness E, no direction.
Note: the mutation of somatic cells can not be directly passed on to offspring, the possibility of germ cells.
4. Importance:
It is the way to produce new genes;
Is the fundamental source of biological variation;
It is the original material of biological evolution.
(2) Gene recombination
1. Concept: refers to gene recombination that controls different characters in the process of biological sexual reproduction.
2. Type:
A. free combination of nonallelic genes on non-homologous chromosomes
B. Cross-exchange of non-sister chromatids in tetrad stage
Chromosome variation in the second quarter
1. Chromosome structural variation:
Example: meow syndrome (partial deletion of chromosome 5)
Type: deletion, repetition, inversion, translocation (reading and understanding)
Second, the variation of chromosome number.
1, type
Single chromosome increase or decrease:
For example: 2 1 trisomy syndrome (1 chromosome)
Increase or decrease in the form of a genome:
For example: triploid seedless watermelon.
Second, the genome
(1) Concept: All chromosomes in diploid gametes form a genome.
(2) Features:
① There are no homologous chromosomes in a genome, and their morphology and functions are different;
② The genome carries all the genetic information that controls the growth of organisms.
(3) Judgment of chromosome number:
(1) Chromosome number = how many chromosomes with the same morphology are there in the cell, and how many chromosomes are there?
② Chromosome number = the number of genes controlling the same trait in the genotype.
3. Haploid, diploid and polyploid
Individuals directly developed from gametes are called haploids.
If there are several chromosomes in somatic cells, individuals developed from fertilized eggs are called polyploids.
Thirdly, the application of chromosome variation in breeding.
1, polyploid breeding:
Methods: The germinated seeds or seedlings were treated with colchicine.
(Principle: It can inhibit the formation of spindle, resulting in chromosome non-separation, thus doubling the number of chromosomes in cells)
Principle: Chromosome variation
Example: cultivate triploid seedless watermelon;
Advantages and disadvantages: The cultivated plants have large organs, high yield and rich nutrition, but low seed setting rate and late maturity.
2. Haploid breeding:
Methods: Pollen (medicine) was cultured in vitro.
Principle: Chromosome variation
Example: Cultivate disease-resistant dwarf rice.
Advantages and disadvantages: the offspring are homozygous, which obviously shortens the breeding cycle, but the technology is more complicated.
Section 5 Human genetic diseases
First, the difference between human genetic diseases and congenital diseases:
L genetic diseases: diseases caused by changes in genetic material. (It can be born or acquired)
Congenital disease: congenital disease. (Not necessarily a genetic disease)
Second, the causes of human genetic diseases: human genetic diseases are human diseases caused by changes in genetic material.
Third, the types of human genetic diseases.
(1) single gene hereditary disease
1. Concept: A genetic disease controlled by a pair of alleles.
2. Reason: Human genetic diseases are human diseases caused by changes in genetic material.
3. Features: It runs in the family and has a high incidence rate (about 20%-25% in China).
4. Type:
(3) Hereditary diseases with chromosomal abnormalities (hereinafter referred to as chromosomal diseases)
1, concept: genetic diseases caused by chromosomal abnormalities. (including the number and structure of anomalies)
2. Type:
Autosomal genetic disease
Structural abnormality: meow syndrome
Abnormal number: 2 1 trisomy syndrome (congenital mental retardation)
Sex chromosome genetic disease: gonadal hypoplasia syndrome (X O type, the patient lacks an X chromosome)
Four. Monitoring and prevention of genetic diseases
1. Prenatal diagnosis: amniotic fluid examination, maternal blood cell examination, B-ultrasound, chorionic villus examination, gene diagnosis.
2. Genetic counseling: to some extent, it can effectively prevent the occurrence and development of genetic diseases.
5. Experiment: Investigate the genetic diseases in the population.
Precautions:
1, investigate the genetic mode-within the family line.
2. Investigate the incidence of genetic diseases-random sampling in the general population.
Note: The larger the survey group, the more accurate the data.
Six, the human genome project:
Determine the entire DNA sequence of the human genome and interpret the genetic information contained in it.
22+XY***24 chromosomes need to be determined.
Chapter 6 from cross breeding to genetic engineering
Section 1 Cross Breeding and Mutation Breeding
1. Comparison of various breeding methods
Section 2 Genetic Engineering and Its Application
First, genetic engineering.
1. Concept: Genetic engineering is also called gene splicing technology or DNA recombination technology. People intend to extract a gene from one organism, modify it, and put it into the cells of another organism to directionally modify the genetic traits of that organism.
2. Principle: Gene recombination
3. Results: The genetic characters of organisms were directionally transformed to obtain the varieties needed by human beings.
Second, the tools of genetic engineering.
1, the scissors of the gene-restriction endonuclease (hereinafter referred to as restriction endonuclease)
(1) Features: specificity and specificity, that is, recognizing specific nucleotide sequences and cutting specific tangents.
(2) site of action: phosphodiester bond
2. The "needle and thread" of genes-DNA ligase
(1) Function: Connect two complementary sticky ends to form a complete DNA molecule.
(2) Connection site: phosphodiester bond
3. Gene vector
(1) Definition: A tool that can deliver foreign genes into cells is a vector.
(2) Species: plasmid, phage and animal and plant viruses.
Third, the operation steps of genetic engineering
1, and extract the target gene.
2. The target gene is combined with the vector.
3. Introduce the target gene into the recipient cell.
4. Detection and identification of target gene
Fourthly, the application of genetic engineering.
1. Genetic engineering and crop breeding: transgenic insect-resistant cotton, storage-resistant tomatoes, saline-alkali resistant cotton, weed-resistant crops, transgenic cows, super sheep, etc.
2. Genetic engineering and drug development: interferon, interleukin, thrombolytic agent, coagulation factor and vaccine.
3. Genetic engineering and environmental protection: superbugs
Verb (abbreviation for verb) Safety of genetically modified organisms and genetically modified foods.
These two views are:
1, genetically modified organisms and genetically modified foods are unsafe and should be strictly controlled.
2. Genetically modified organisms and genetically modified foods are safe and should be widely promoted.
The way to learn biology well is 1. Go back to the textbook and clarify the concept. The first point can lay the foundation for understanding memory.
2. Memorize the theoretical knowledge in the workbook. The school will issue some workbooks, and all the knowledge points will be summarized in the workbooks. The real knowledge is in the review materials. What you should read is actually a workbook. Reading textbooks only lays a good foundation for understanding the endorsement process. Don't just wander around in the textbook! After finishing the previous work, you can take the time to memorize these knowledge points and study systematically. Ask the teacher at the first time when you encounter something you don't understand.
3. do the problem. After completing the first two tasks, you can do the exercises in the workbook. At this time, because you have really studied systematically, you are no longer unfamiliar with the language in the biology questions, and the correct rate of doing the questions will be greatly improved. This job can consolidate your memory knowledge.
4. Correct the mistakes and make a summary. Correct it yourself after you finish the problem. After you finish a problem, you should learn the knowledge points that you haven't learned in systematic learning from the analysis of this problem. Tick the question number or option with a red pen to indicate that this is a new knowledge point and review it later.
5. Review knowledge points and wrong questions in time. Don't just recite it once and everything will be fine. Review it every once in a while, remember it repeatedly, and deepen your impression. You will find that with the increase of the number of re-offers, the speed of endorsement is accelerating, that is, memory becomes easier and easier.
How to review biology is better? 1. Grasp the basic knowledge points.
Like other sciences, the knowledge of biology should be memorized on the basis of understanding, but senior three biology has some different characteristics from other sciences.
Students are already very clear about some basic thinking elements of mathematics, physics and chemistry that you have studied for many years. But for biology, students should think about strange cells, tissues and strange logical relationships between various organic and inorganic substances. Therefore, in order to improve their biological performance, they need to remember these nouns and terms before they can master them, which is called "remember first, then understand".
2. Make clear the internal connection of knowledge.
After sorting out these basic terms, nouns and concepts, students need to focus on learning the laws of biology. At this time, everyone should pay attention to the understanding of various biological structures and the practice among groups. This is the clue of the main knowledge system.
3, a deep understanding of key knowledge
Have a deep understanding of some key points and knowledge difficulties. How to achieve a deep understanding? When reading, students should always think about the six W's, WHO-who or what structure; What-what has changed or happened; How it happened; When-when or in what order; In what place or structure; Why-→ Why did this change happen? Everyone insists on thinking about these six w's often, and I believe there will be no small gain.
What are the relevant articles about the knowledge points of compulsory biology in senior two?
★ Two compulsory knowledge points of high school biology
★ Summary of knowledge points in the second chapter of compulsory biology in senior high school
★ Summary of Important Knowledge Points in Chapter 1 of Compulsory Biology II
★ Summary of knowledge points in the third chapter of compulsory biology in senior one.
★ Senior one needs two knowledge points.
★ Summary of the Outline of Two Required Knowledge Points in Biology
★ Summary of Two Necessary Knowledge Points of Biology in Senior High School
★ Induction of two compulsory knowledge points in senior one biology.
★ Summary of Two Error-prone Knowledge Points in Senior High School Biology Compulsory Course
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