Summary of three knowledge points of biology elective course in senior high school

Elective Course 3, Special Topics of Modern Biotechnology

Topic 1, genetic engineering

What is genetic engineering?

1.1the basic tool of DNA recombination technology

The first is the "molecular scalpel"-restriction endonuclease (restriction endonuclease)

One source: mainly isolated and purified from prokaryotes.

It has two functions: it can recognize the specific nucleotide sequence of double-stranded DNA molecules and break the phosphodiester bond between two nucleotides in a specific part of each chain, so it has specificity.

Results: The ends of DNA fragments produced by restriction endonuclease cleavage usually have two forms: sticky end and flat end.

Second, the "molecular suture needle"-DNA ligase

One function: splicing the cut DNA fragments into new DNA molecules. Connection site: phosphodiester bond, not hydrogen bond.

Comparison of two DNA ligases (Escherichia coli DNA ligase and T4-DNA ligase): 1. Similarity: both of them have phosphodiester bonds. 1. Difference: E.coli DNA ligase comes from T4 bacteriophage and can only connect phosphodiester bonds between complementary sticky ends of double-stranded DNA fragments; T4DNA ligase can suture two kinds of ends, but the efficiency of connecting blunt ends is low.

Similarities and differences between DNA polymerase and DNA polymerase: DNA polymerase can only add a single nucleotide at the end of the existing nucleotide fragment to form a phosphodiester bond. DNA ligase connects the ends of two DNA fragments to form phosphodiester bond.

Third, "molecular transport tool"-carrier (what is the difference between carrier and cell membrane? )

The necessary conditions for becoming a vector: it can be replicated in recipient cells and stored stably; It has one or more restriction enzyme cutting points for inserting foreign DNA fragments; Having marker genes for identifying and selecting recombinant DNA; It is harmless to recipient cells and easy to separate.

The most commonly used vector is plasmid: it is naked, simple in structure, independent of bacterial chromosomes and has the ability of self-replication. Other vectors: derivatives of phage, animal and plant viruses.

1.2 Basic operating procedures of genetic engineering

First, the acquisition of the target gene (what is the target gene? )

One of the acquisition methods: prokaryotic genes are obtained by direct separation, and eukaryotic genes are obtained by artificial synthesis.

Obtaining the target gene from the gene library

What is a gene bank? What is a genome library? What is a partial gene library? What is the relationship between the three?

How to get the target gene from the gene bank?

Thirdly, the target gene was amplified by PCR.

1. What is PCR technology? Principle: DNA double-stranded replication. 3. 3. What are the necessary conditions for PCR technology? What is the result of PCR?

2. Process: denaturation → annealing → extension → repeated many times. Direct artificial synthesis.

Second, the construction of gene expression vector (this process is actually the process of gene recombination from different sources, which is the core of genetic engineering)

What is the purpose of constructing gene expression vector? How to build it?

The composition of gene expression vector: replication origin+promoter+target gene+terminator+marker gene.

What are promoters and terminators? Where are they on the gene expression vector? What are their respective roles? What is the function of marker genes?

Thirdly, the target gene is introduced into the recipient cell.

The concept of transformation: it is the process that the target gene enters the recipient cell and remains stable and expressed in the recipient cell.

Two common conversion methods

1. Introducing the target gene into plant cells: Agrobacterium transformation is the most commonly used method, followed by particle bombardment and pollen tube pathway method. Where is it introduced into plant cells?

4. Introducing the target gene into animal cells: The most common method is microinjection. The recipient cells of this method are mostly fertilized eggs.

3. Introducing the target gene into microbial cells: What are the advantages of prokaryotes as recipient cells? What is the most commonly used prokaryotic cell? What is the transformation method?

After recombinant DNA is introduced into recipient cells, the basis for screening recipient cells containing gene expression vectors is whether the marker gene is expressed or not.

4. Detection and expression of target gene

First, it is necessary to detect whether the target gene is inserted into the chromosomal DNA of transgenic organisms. Methods: DNA molecular hybridization technique. What is the principle of this method?

Secondly, it is necessary to detect whether the target gene has transcribed mRNA. Methods: The labeled target gene was used as a probe to hybridize with mRNA.

Finally, whether the target gene is translated into protein is detected. Methods: protein was extracted from transgenic organisms, and the corresponding antibodies were used for antigen-antibody hybridization.

Sometimes it is necessary to identify the biological level of an individual. For example, whether transgenic insect-resistant plants have insect-resistant characteristics.

1.3 application of genetic engineering

1. Plant genetic engineering: Plants with insect resistance, disease resistance and reversion resistance can improve the quality of plants through transgenic technology.

Animal genetic engineering: improve the growth rate of animals, improve the quality of livestock products, and use transgenic animals to produce drugs as donors for organ transplantation.

Genetically engineered drugs: cytokines, antibodies, vaccines, hormones, etc.

4. Gene therapy: It is the most effective way to treat genetic diseases by introducing normal foreign genes into patients and making the expression products of genes play a role to achieve the purpose of treating diseases.

1.4 the rise of protein project

1. Why can't natural protein fully meet the needs of production and use? What is the basic realization mode of protein Project?

2. protein Project: According to the structural law of protein molecules and the relationship between their biological functions, the existing protein was transformed or made into a new protein through gene transformation or gene synthesis to meet the needs of human production and life. (In principle, genetic engineering can only produce protein that already exists in nature)

Topic 2, Cell Engineering

What is cell engineering? According to the different operating objects, what kinds can they be divided into?

2. 1. 1 basic technology of plant cell engineering

First, the theoretical basis (principle): cell totipotency.

What is the totipotency of cells? Why don't cells show totipotency during biological growth and development?

The difficulty of totipotency expression: fertilized egg > germ cell > stem cell > somatic cell; Plant cells > animal cells.

Advances in plant tissue culture technology

What is plant tissue culture? What is dedifferentiation? What is the essence of dedifferentiation? What is the result of dedifferentiation? What is redifferentiation? What is calluses and what are their characteristics?

State 2: Cultivating new plant varieties is the last process of cultivating transgenic plants and plant somatic hybridization.

Third, the process of plant somatic hybridization technology

What is the first obstacle to plant somatic cell fusion? What is a gentle way to tear down the wall? Will protoplasm merge naturally when put together?

What is plant somatic hybridization? Three meanings: overcoming the obstacle of distant hybridization incompatibility between different organisms.

What is the difference between traditional sexual hybridization and somatic hybridization in this section? (reproductive mode; Species)

2. 1.2 practical application of plant cell engineering

First, a new way of plant reproduction.

Micropropagation. What is micropropagation technology of plants?

What are the advantages of micropropagation technology? (the copying speed is fast; Maintain maternal characteristics; Not limited by the natural growing season)

2. Virus-free crops. What are the symptoms after asexual reproduction crop poisoning? What is crop detoxification?

3. Artificial seeds. What are the defects of natural seeds? What is artificial seed? What are the advantages?

Second, the cultivation of new crop varieties.

Haploid breeding. What is haploid breeding? What is the principle? What are the common methods? What are the advantages?

Using two mutants. Why is tissue culture prone to mutation?

3. Comparison of virus-free crops, artificial seeds and haploid breeding. 1. Similarity: micropropagation technology was used in the cultivation process. Difference: crop detoxification emphasizes that materials must be non-toxic; Embryoids, adventitious buds, terminal buds and axillary buds can be obtained from artificial seeds only by culture. Haploid breeding is essentially sexual reproduction.

Industrial production of cell products. What are the main cell products that people use?

2.2. 1 animal cell culture and nuclear transfer technology

What are the common technical means of animal cell engineering? Which of these projects is the basis of other animal cell engineering technologies?

First, animal cell culture

One concept: animal cell culture is to take out relevant tissues from animals, disperse them into single cells, and then put them into suitable culture medium to allow these cells to grow and reproduce.

Two processes: taking materials → dispersing → preparing suspension → primary culture → subculture. How are each step handled separately?

1. Why should cells be dispersed before cell culture?

2. What is cell adhesion? What is contact inhibition? 3. What is primary culture? What is a subculture?

4. Why are the cells used for nuclear transplantation usually within 10 generation? What are the characteristics of cells after 10 generation?

Three animal cell culture needs to meet the following conditions (what is the internal environment? What are the effects of internal environment and steady state on cells? )

1. Sterile and nontoxic environment. The culture solution should be sterilized. Usually, a certain amount of antibiotics should be added to the culture solution to prevent pollution in the culture process. In addition, the culture medium should be changed regularly to prevent the accumulation of metabolites from harming the cells themselves.

1. Nutrition: Composition of synthetic medium: sugar, amino acids, growth promoting factors, inorganic salts, trace elements, etc. It is usually necessary to add natural ingredients such as serum and plasma.

3. Temperature and pH. Suitable temperature: 36.5℃ 0.5℃ for mammals; PH value: 7.2~7.4.

Gas environment. 95% air +5% carbon dioxide. O2 is necessary for cell metabolism, and the main function of CO2 is to maintain the pH value of the culture medium.

Application of animal cell culture technology: preparation of virus vaccine, interferon and monoclonal antibody, detection of toxic substances, and culture of various cells for medical research.

Comparison between animal cell culture and plant cell (tissue) culture

Comparison of project principles, culture medium results, culture environment and culture purpose

Plant tissue culture cell totipotent solid; Nutrients and hormones can be cultivated into in vitro micropropagation of plants and detoxification of crops.

Animal cell culture cell proliferation solution; Nutrients, animal serum and so on. Culture into cell groups in vivo or in vitro to obtain cell products or cells.

Two, animal somatic cell nuclear transfer technology and cloned animals

Why can't animal cell culture obtain complete animal individuals? What is animal nuclear transplantation? What is a cloned animal?

One type: embryo nuclear transfer (relatively easy); Somatic cell nuclear transfer (difficult).

Second, the reason for choosing enucleated oocytes: oocytes are relatively large and easy to operate; Oocytes are rich in cytoplasm and nutrition.

The process of three-body nuclear transfer: taking donor animal somatic cells → donor cell culture → fusion of donor cells and enucleated oocytes → recombinant cells → early embryos → moving into the uterus of recipient animals → cloning animals.

1. Why use oocytes as recipient cells? Which stage of oocyte is selected? How to take out the oocyte nucleus?

How to fuse donor cells and recipient cells? How to activate receptor cells? What is the purpose of activation?

Application prospect of tetranuclear transfer technology

1. Accelerate the process of genetic improvement of livestock and promote the cultivation of excellent herds; 1. Protect endangered species and increase the number of survivors; 3. Producing precious medical protein; 1. As a donor of xenotransplantation; 5. Used for transplantation of tissues and organs.

Problems of five-body nuclear transfer technology: cloned animals have health problems, showing genetic and physiological defects.

2.2.2 Animal cell fusion and monoclonal antibody

1. What is animal cell fusion?

2. The principle of animal cell fusion is basically the same as that of plant protoplast fusion, and the method of inducing animal cell fusion is similar to that of plant protoplast fusion. Commonly used inducing factors are polyethylene glycol, inactivated virus and electrical stimulation.

Significance of animal cell fusion: It overcomes the incompatibility of distant hybridization and becomes an important means to study cytogenetics, cellular immunity, tumor and the cultivation of new biological varieties.

4. Comparison between animal cell fusion and plant somatic hybridization

Comparison of project principles and methods, and main uses of inductive means.

Cell membrane fluidity and cell totipotency of protoplast fusion induced by plant somatic hybridization physical and chemical methods to overcome the incompatibility barrier of distant hybridization and obtain hybrid plants

The fluidity of animal cell fusion cell membrane disperses cells and induces cell fusion, and monoclonal antibodies are prepared by physical, chemical and biological methods.

5. Monoclonal antibody: Using a single B lymphocyte for asexual reproduction to form a cell population may produce antibodies with single chemical properties and strong specificity.

What are the traditional antibody production methods and defects? What are the characteristics of B lymphocytes? Preparation technology of two monoclonal antibodies

Animal cell fusion (1) Materials: myeloma cells and antigen-stimulated B lymphocytes. (Two kinds of mouse cells were selected because the same kind of cells were successfully hybridized; What are the characteristics of these two kinds of cells? )

⑵ Fusion: Physical, chemical and biological methods can be used for induction (how many fusion methods will there be? ); ⑶ Screening hybridoma cells with selective medium. What are the characteristics of these cells? Why? )

Animal cell culture (1), cloning, culture and antibody detection of hybridoma cells, and screening hybridoma cells that can secrete the required antibodies; ⑵ Large-scale culture in vivo or in vitro. Can mouse monoclonal antibodies be used to treat human diseases? )

Advantages of the three monoclonal antibodies: strong specificity, high sensitivity and large-scale preparation.

The application of monoclonal antibody as a diagnostic reagent: it has the advantages of accuracy, high efficiency, simplicity and rapidity by accurately identifying the subtle differences of various antigen substances and specifically binding with some antigens. 1. Used to treat diseases and carry drugs: mainly used for cancer treatment, and can be made into "biological missiles" (which parts are composed of? What are their respective roles? ), a small amount is used to treat other diseases.

Topic 3, Embryonic Engineering

What is embryo engineering? What technologies are mainly included?

3. 1 In vivo fertilization and early embryo development

First, the appearance of sperm and eggs.

1. Where sperm appears: testis. Period: from the beginning of estrus to the decline of reproductive function.

3. Process (1) Spermatogonia → Polyspermatogonia → Primary spermatocytes → Secondary spermatocytes → Sperm cells → Sperm (in which the nucleus becomes the main part of the sperm head; Golgi apparatus developed into acrosome of the head; The centrosome evolved into the tail of sperm; Mitochondria form mitochondrial sheath; Other substances are condensed into protoplasm drops)

4. What are the main changes in the process of sperm cells becoming sperm? Why did the nucleus and mitochondria remain? Why do mitochondria concentrate at the base of the tail?

⑵ Mature sperm: It looks like a tadpole and consists of three parts: head, neck and tail. Is there a relationship between sperm size and animal size?

2. Where the egg occurs: the ovary. 4. Stage: Embryo after sex differentiation.

13. process: oocyte → multiple oocytes → primary oocytes → secondary oocytes → oocytes.

When and where were the two meiosis completed?

2. Follicles are mainly composed of oocytes and follicular cells, and the oocytes growing follicles and surrounding follicular cells protrude into the follicular cavity to form cumulus. Ovulation: The process in which the oocyte, the surrounding zona pellucida (composed of glycoprotein) and the radial crown (a layer of follicular cells outside the zona pellucida) are expelled from the follicle. After ovulation, corpus luteum is formed in the follicular position.

Is the newly discharged egg a mature egg? Where is it fertilized with sperm in the mother?

3. Similarities between sperm and egg cells: in the initial stage, they both undergo mitosis, which increases the number of germ cells; Sperm and eggs can only be formed after two meiosis.

Difference: one spermatogonia → four sperms; An oogonium → an egg; Sperm is tadpole-shaped; Eggs are spherical; The formation of sperm begins in estrus, and the formation and storage of eggs in ovaries of most mammals are completed before the birth of the fetus.

Second, the concept of fertilization 1: refers to the process of combining sperm and eggs to form a fertilized egg (ie fertilized egg).

Sign: When two polar bodies can be observed in the gap between yolk membrane and zona pellucida. 3. location: fallopian tube.

2. Process (1) Preparation stage before fertilization 1- Sperm capacitation: that is, sperm can acquire fertilization ability only after corresponding physiological changes have taken place in female reproductive tract.

Preparation stage 2-Preparation of eggs: Only when the eggs reach the binary fission metaphase of meiosis in the fallopian tubes can they be fertilized.

⑵ Fertilization stage: sperm and egg meet → acrosome reaction (→ acrosin release → dissolving cumulus cells (radiation crown) → crossing the radiation crown → contacting zona pellucida → acrosin dissolving zona pellucida → crossing the zona pellucida) → contacting yolk membrane → generating zona pellucida reaction → forming the first barrier → sperm being embraced by microvilli → sperm merging with yolk membrane → sperm entering the egg → generating yolk membrane sealing effect → ① Fertilization stage.

② What is acrosome reaction? What is zona pellucida reaction? What is yolk membrane seal? What do they do respectively?

③ What are female and male pronuclei? When did they form?

Four meanings: keeping the number of chromosomes in somatic cells of each organism's offspring unchanged; It is very important for the inheritance and variation of organisms.

Embryo development: refers to the process in which fertilized eggs develop into larvae. The fertilized egg initially develops in the fallopian tube and undergoes mitosis.

Split stage. Characteristics: During mitosis in zona pellucida, the number of cells increases continuously, but the total embryo volume does not increase or decreases slightly.

The second morula. Characteristics: When the number of embryonic cells reaches about 32, the embryo forms a dense cell mass that looks like a mulberry. This is a kind of totipotent cell.

Triblastocysts。 Characteristics: Cells begin to differentiate (cell totipotency is still relatively high in this period). There are trophoblast cells outside, which will develop into fetal membrane and placenta; The larger cells gathered at one end of the embryo are called inner cell masses, which will develop into various tissues of the fetus in the future. The cavity in the middle is called blastocyst cavity. What is incubation?

Four gastrula embryos. Characteristics: With the differentiation of three germ layers, there are blastocyst cavities and gastrula cavities.

3.2 In vitro fertilization and early embryo culture

First, in vitro fertilization

Collection and culture of oocytes

Main method: Use gonadotropin to make it excrete more eggs. Then, the egg is washed out from the fallopian tube and directly fertilized with capacitated sperm in vitro. The second method: collecting oocytes from the ovaries of newly slaughtered female animals; The third method is to directly suck oocytes from the ovaries of living animals through ultrasonic detectors and laparoscopy. The collected oocytes must be artificially cultured and matured in vitro before they can be fertilized with capacitated sperm.

Sperm collection and capacitation methods: false vagina method, hand holding method and electrical stimulation method.

4. capacitation treatment: sperm should be capacitated (1) before in vitro fertilization. culture method: sperm should be taken out of epididymis and cultured in artificial capacitation solution for a period of time to obtain capacitation. Such as rodents, rabbits and pigs. ⑵ Chemical method: Sperm was placed in a certain concentration of heparin or calcium ion carrier A23 187 solution, and sperm capacitation was induced by chemical drugs. Such as cattle and sheep.

Third fertilization: capacitated sperm and cultured mature egg cells complete the fertilization process in capacitated fluid or special semen.

Second, early embryo culture.

Early embryo culture: After in vitro fertilization of sperm and eggs, the fertilized eggs should be transferred to the development medium for further culture, so as to check the fertilization status and the developmental ability of the fertilized eggs. The composition of culture medium is complex. Besides some inorganic salts and organic salts, vitamins, hormones, amino acids, nucleotides and other nutrients, as well as serum and other substances need to be added. When the embryo develops to a suitable stage, it can be taken out, transplanted to the recipient or frozen. Different animals have different embryo transfer times.

3.3 Application and prospect of embryo engineering

First, embryo transfer. What is embryo transfer? What is a "donor"? What is a "receptor"? (The donor is an excellent breed, and the female animal as the recipient should be an ordinary or large original breed. )

Current situation: Any embryo produced by embryo engineering technology, such as transgenic, nuclear transfer or in vitro fertilization, must go through embryo transfer technology to obtain offspring, which is the last "process" of embryo engineering.

Present situation and significance of embryo transfer. Accelerate breeding and variety improvement; 4. Save a lot of money to buy breeding stock; 3. One child is prolific; 4. Protect variety resources and endangered species; 5. It can give full play to the reproductive potential of excellent female individuals, shorten the reproductive cycle and increase the number of offspring bred in a lifetime.

Physiological basis: 1. After an animal is in estrus and ovulates, the physiological changes of the donor and recipient reproductive organs of the same animal are the same. This provides the same physiological environment for the donor embryo to move into the recipient.

Early embryos are free for a certain period of time. This makes it possible to collect embryos.

3. The recipient has no immune rejection to foreign embryos transplanted into uterus. This provides the possibility for the survival of embryos in the recipient.

Donor embryos can establish normal physiological and tissue contact with the recipient uterus, but the genetic characteristics of donor embryos are not affected during pregnancy.

The basic procedures mainly include

1. Selection and treatment of donors and recipients. Select donors with excellent genetic characteristics and production performance, and recipients with normal physical health and reproductive ability. Donors and recipients are the same species. Hormone synchronization and gonadotropin superovulation in donor cows. (1) Selection of donors and recipients (1) Donors: individuals with excellent genetic and productive performance; ② Receptors: healthy and normal reproductive individuals. ⑵ Treatment: Estrus synchronization. Specific practice: injection of related hormones.

3. Collect oocytes. Methods: Gonadotropin was injected to make the donor superovulate.

13. Breeding or artificial insemination. Sperm source: excellent male animals of the same species.

Collection, examination, culture or preservation of embryos. On the 7th day after mating or insemination, the embryo in the uterus of the donor cow is washed out with a special egg washer (also called egg washing). Check the quality of the embryo. At this time, the embryo should develop to the stage of mulberry or blastocyst. Transplanted directly into the recipient or stored in-196℃ liquid nitrogen.

5. Transfer embryos. ⑴ Operation method: Take out the recipient uterus and ovary, inject the embryo into the uterine horn, and suture the wound.

⑵ Non-surgical method: Send the transplantation tube with embryo to the corresponding part of the recipient cow uterus for embryo injection.

[6] Post-transplant examination. Check whether the recipient cow is pregnant.

Second, the concept of embryo segmentation: refers to the technology of cutting early embryos into 2 equal parts and 4 equal parts. Obtain identical twins or multiple births through transplantation.

The second meaning: the offspring from the same embryo have the same genetic material and belong to asexual reproduction.

Theoretical basis: totipotency of animal embryonic cells. Therefore, the stage of embryo segmentation is a well-developed morula or blastocyst with normal morphology.

Operation flow: cut the embryo with a cutting needle or blade, suck out half of the embryo and inject it into the prepared empty transparent belt, or directly transplant the exposed half of the embryo to the recipient. The main instruments used are solid-state microscope and micromanipulator. Matters needing attention in operation: 1. When the blastocyst embryo divides, the inner cell mass should be equally divided. The reason is that the inner cell mass generally does not appear until the blastocyst stage. It is the basic cell that develops into the embryo itself, and other cells are the trophoblast, which only provides nutrition for the development of the embryo and fetus. If the inner cell mass cannot be divided equally, there will be problems such as the normal development ability of the part with more inner cell mass is strong, and the development of the part with less inner cell mass is blocked or stunted, or even unable to develop. The more copies of embryo segmentation, the more difficult the operation and the lower the success rate of transplantation.

Defects of embryo segmentation technology. Newborn animals are low in weight, and there are still differences in coat color and markings; The possibility of using embryo segmentation technology to produce identical multiple births is limited.

Third, embryonic stem cells-what is mammalian embryonic stem cells?

Two characteristics 1. Morphology: small size, large nucleus and obvious nucleoli; Function: it has developmental totipotency and can differentiate into any kind of tissue cells in adult animals; 13. Under the condition of in vitro culture, ES cells can proliferate without differentiation. It can be frozen or genetically modified.

Three main uses: 1. It can be used to study the individual development and development law of mammals; It is an ideal material for studying cell differentiation in vitro. Adding taurine and other chemicals to the culture medium can induce es cells to differentiate into different types of tissue cells, which provides an effective means to reveal the mechanism of cell differentiation and apoptosis. 3. It can be used to treat some chronic diseases of human beings, such as Parkinson's syndrome and juvenile diabetes. 2. Using the characteristics of being induced to differentiate into new tissue cells, transplanted ES cells can repair necrotic or degenerated parts and restore normal functions; With the development of tissue engineering technology, artificial tissues and organs can be directionally cultured by inducing es cells to differentiate in vitro, which can be used for organ transplantation to solve the problems of insufficient donor organs and immune rejection after organ transplantation.

Topic 4: Safety and Ethical Issues of Biotechnology

4. 1 Safety of genetically modified organisms

I. Genetic biology and food safety

Objection: Oppose "substantial equivalence", lag effect, new allergens and changes in nutritional components.

Positive views: safety evaluation, scientists' responsible attitude, no evidence.

Second, genetically modified organisms and biosafety: the impact on biodiversity.

Objection: It may cause "genetic pollution" if it spreads out of the planting area and becomes a wild species, an alien invasive species, and recombines harmful pathogens to become super weeds.

Positive views: limited vitality, reproductive isolation, limited pollen transmission distance and limited pollen survival time.

Three, genetically modified organisms and environmental security: the impact on the stability of the ecosystem.

Contrary view: breaking species boundaries, secondary pollution, harmful pathogenic microorganisms and toxic protein recombination may enter the human body through the food chain.

Positive view: do not change the original classification state of organisms, reduce the use of pesticides, and protect the farmland soil environment.

4.2 Pay attention to ethical issues of biotechnology

1. Human cloning: There are two different views, and most people hold a negative attitude.

Negative reasons: human cloning is a serious violation of human ethics and an abuse of cloning technology; Human cloning has impacted the existing traditional ethical concepts such as marriage, family and sexual relations. Human cloning is a person whose psychological and social status is not perfect because of artificial creation.

Positive reasons: Technical problems can be solved by embryo grading, gene diagnosis and chromosome examination. Immature technology can only be matured through practice.

China government's attitude: reproductive cloning is prohibited and therapeutic cloning is not opposed. Four No Principles: Disapproving, disallowing, supporting and not accepting any experiment of reproductive cloning of human beings.

Second, IVF: There are two differences between the two purposes of IVF. Most people agree with different views.

Negative reasons: treating IVF as a human body parts factory is a disrespect for life; Early life also has the right to live. Abandoning or killing redundant embryos is tantamount to "murder".

Positive reasons: It solves the problem of infertility, provides the best and fastest method for treating patients with bone marrow hematopoietic stem cells, and will not cause damage to IVF.

Third, the genetic identity card.

Reasons for denial: the disclosure of personal genetic information leads to genetic discrimination, which will inevitably lead to serious consequences such as genetic unemployment, personal marriage difficulties and interpersonal alienation.

Positive reasons: Through genetic testing, preventive measures can be taken as soon as possible and timely treatment can be carried out to save patients' lives.

4.3 Prohibition of biological weapons

1. Biological weapons: Biological warfare agents and weapons and equipment using biological warfare agents are collectively referred to as biological weapons. Biological warfare agents refer to microorganisms and their toxins that make people and livestock sick and damage crops in war.

Category: pathogenic bacteria, viruses, biochemical agents, pathogenic bacteria after gene recombination.

Mode of transmission: inhalation, ingestion, contact with infected articles, bite by infected insects, etc.

Features: strong pathogenicity, the strongest infectivity, many ways of infection, wide pollution area, long incubation period, difficult to be found, long harm time and so on. 5. The Biological Weapons Convention and the attitude of the Government of China.

Theme 5, Ecological Engineering

Concept: Ecological engineering refers to the application of the basic principles and methods of ecology and systematics, through system design, regulation and technical assembly, to repair and rebuild the destroyed ecological environment, improve the traditional production mode that causes environmental pollution and destruction, and improve the productivity of the ecosystem, thus promoting the harmonious development of human environment in social and natural.

5. 1 Basic principles of ecological engineering

What is ecological economy? How can we realize ecological economy (circular economy)?

Basic principles of ecological engineering

First, the principle of material recovery. Theoretical basis: material cycle. For example, "waste-free agriculture".

Second, the principle of species diversity. Theoretical basis: ecosystem stability. Characteristics: The richer the species, the higher the resistance stability of the ecosystem.

Third, the principle of coordination and balance. Theoretical basis: coordination and balance between biology and environment.

Fourth, the principle of good faith. Theoretical basis: a huge system composed of society, economy and nature.

5. Principles of systematics and engineering. The structure of the system determines the functional principle. Theoretical basis: Distributed is better than centralized and ring. Principle of system integrity. Theoretical basis: the overall function is greater than the sum of its parts.

5.2 Ecological Engineering Examples and Development Prospects

I. Examples of Ecological Engineering

Rural comprehensive development ecological project. Problem: Multi-level utilization of materials and energy in rural areas. Countermeasures: carry out comprehensive development-oriented ecological engineering.

The second small watershed comprehensive management ecological project. Problem: Soil erosion in small watersheds. Countermeasures: comprehensive management.

Three regional ecosystem restoration projects. Problem: Land desertification in China. Countermeasures: planting trees, returning farmland to forests and grasslands, etc.

Wetland ecological restoration project. Problem: Shrinkage and destruction of wetlands. Countermeasures: controlling pollution, returning farmland to lakes, etc.

Ecological restoration project of abandoned land in mining area. Problem: the destruction of the ecological environment in the mining area. Countermeasures: repair land and restore vegetation.

6. Urban environmental ecological engineering. Problem: Pollution problems such as garbage, air and noise faced by urban ecosystem. Countermeasures: comprehensive management of urban greening, sewage purification and garbage disposal.

Ecological engineering also has its limitations. Only by preventing ecological damage and exerting the natural restoration ability of the ecosystem is the fundamental way out.

Second, the prospect of ecological engineering development

What are the experiments and revelations of Biosphere II?

Analysis and Prospect of Ecological Engineering Development in China

What are the characteristics of ecological engineering in western countries?

What are the problems and development prospects of ecological engineering in China?