First, the teaching purpose
1. Through the investigation of recent newspapers, magazines and other media, understand the recent development of biotechnology and its impact on human society.
2. Learn the methods of collecting and processing biotechnology information.
3. Improve the ability of language expression and information exchange by making communication reports and classroom discussions.
Second, teaching suggestions
Teachers should pay attention to the following points when guiding students to carry out this research.
1. Provide students with the names of media that report the development of biotechnology, such as newspapers, magazines, books, TV programs, radio programs and the Internet, and guide students to analyze the information characteristics of different media reports, focusing on comparing their differences in timeliness, accuracy, popularity and authority.
2. In order to reduce students' repetitive work as much as possible, teachers should divide students into several groups, at least six groups, and investigate the reports of different media on the development of biotechnology.
3. It is best to specify the time range for investigating media reports, such as news reports in the past 1 ~ 2 years.
4. Teachers should roughly define the scope of information collection, such as new discoveries, new inventions, new technologies and new progress. Students should also be asked to collect the new progress of other natural disciplines and make a quantitative comparison with the new progress of biological science and technology.
5. Organize students to discuss the information obtained by students through media investigation, and guide students to classify (there may be different classification methods).
6. Teachers should guide students to complete the communication report independently, and the report form need not be unified. Students should be encouraged to give full play to their talents and determine the report forms that can give full play to their specialties. For example, a written explanation is best illustrated by examples; Draw a chart, concise and to the point, which can explain the problem; Making slides can integrate pictures, charts and short text descriptions; To make a video tape, you can combine similar content played in related TV programs to make a video clip, preferably with a voice-over explanation; You can also do computer courseware.
7. The way of communication and presentation of the report can be arranged according to the conditions of our school. For example, use the blackboard newspaper in the class to regularly publish the information on the development of biotechnology collected by students. It can also be displayed in the form of information tabloids on biotechnology development, and students can be organized to visit and read in class and between classes. You can also use 1 hour of extracurricular activities to focus on playing video clips or courseware made by students, which are explained by students themselves. Conditional schools can also organize students to hold "press conferences" or "academic reports".
8. When organizing students' discussion, ask students to evaluate the timeliness and authority of the information they collected.
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This research project designs experiments to observe the effects of auxin or auxin analogues on plant growth and development.
First, the teaching purpose
1. Initially learn to design experimental methods to observe the effects of auxin or auxin analogues on plant growth and development.
Learn to observe the phenomena in the experiment, analyze the observed phenomena and come to your conclusion.
Second, teaching suggestions
Teachers should pay attention to the following points when guiding students to carry out this research topic.
1. Teachers should make necessary preparations for students to design experimental schemes and conduct experiments.
(1) Introduce some relevant reference materials to students, such as the textbook Plant Physiology, Biological Bulletin, middle school biology experiment books, biotechnology activity books, flower cultivation books, etc.
(2) Introduce some common Chinese names of auxin and its analogues to students and compare them with English abbreviations. For example, indole acetic acid (IAA), indole propionic acid (IPA), indole butyric acid (IBA), naphthylacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-d).
(3) Introduce the characteristics of auxin and several auxin analogues to students, and provide the basis for selecting materials for students to design experiments.
IAA: unstable in plants, easily decomposed by strong light, unstable in effect, not as good as IBA and NAA.
IBA: It is not easy to be oxidized and decomposed, and it is easy to remain in the treated parts. Strong action, long action time, many and long roots, but the price is more expensive.
NAA: The effect is similar to IBA, and the induced roots are few and thick. It is cheap and safe to use.
(4) Introduce the use of auxin and its analogues. In experiments, three different substances, water solution, powder or lanolin ointment containing drugs, are usually treated, and the concentration unit is mg/L. When in use, the parts of plant organs to be treated are soaked in water solution for a certain period of time, or dipped in powder or coated with lanolin ointment.
2. Before designing experiments, teachers should teach students the idea of designing experiments.
(1) Determining the topic Because the scope of this "research topic" is large, teachers can guide students to choose smaller suitable topics for research according to the local actual situation and the conditions of our school, such as "the influence of NAA on the rooting of XX plant cuttings" or "the influence of 2,4-D on the fruits of XX plants".
(2) Make assumptions about the content of your own experiment. For example, NAA can restore the dividing ability of parenchyma cells at the base of cuttings (treated with NAA), produce callus and grow adventitious roots.
(3) Design control experiment In this study, in order to explore the concentration range of auxin analogues that affect plant growth and development, several experimental groups with different concentrations must be designed as mutual controls. When designing the experimental device, students should be reminded that the design of the device should be conducive to observation. For example, experiments to promote rooting can be observed by hydroponics.
(4) Observe and record the phenomena or results in the experiment, and carefully record them.
(5) After the verification experiment is completed, if time permits, it is best to repeat the original experiment. If it can be repeated successfully, the hypothesis holds.
3. In order to reduce the repeated experiments between students as much as possible, teachers should allocate the experimental contents (sub-topics) as much as possible. Just as the same auxin analogues affect the growth and development of different plants, different organs of the same plant and different auxin analogues affect the growth and development of an organ of a plant. At the end of the experiment, students with the same or similar experimental contents will be organized for comparative analysis.
Teachers should ask students to carefully observe and record the changes of plant growth and development before, during and after the experiment. We should not only record the phenomena that are in line with expectations, but also record the phenomena that are not in line with expectations. Try to collect the data that can be collected during the experiment.
5. After the experiment, teachers should teach students how to analyze the experimental results carefully and deal with the experimental data scientifically, such as using tables or function diagrams as much as possible. It is also necessary to guide students to use experimental facts for scientific reasoning and draw corresponding conclusions. Finally, complete the experimental report.
6. The experimental part of this topic is all arranged after class or at home.
7. After the project report is completed, teachers should organize students to communicate. When organizing students to exchange reports, teachers should not only let students exchange their own experimental reports, but also let students report their own experiences in completing this topic, such as experiences, lessons and ways to overcome difficulties.
Third, reference materials.
Physiological function of indoleacetic acid
1. Promotion. IAA promotes the formation of adventitious roots and lateral roots, the elongation of stems, the expansion of leaves, the shedding of old leaves, the flowering of some plants, the increase of female flowers, the growth of ovary walls, parthenocarpy, fruit growth, fruit setting, seed growth and seed germination.
2. inhibition. IAA makes lateral branches grow, tubers form, young leaves fall off, flowers fall off and fruits fall off.
Whether IAA promotes or inhibits leaf abscission depends on the source of IAA. If IAA is transported from stem to leaf, it will promote the shedding of old leaves. If IAA is transported from leaves to stems, it will inhibit the shedding of its own leaves. The promotion and inhibition of IAA on fruit abscission are similar.
Physiological effects of auxin analogues
1.IBA, NAA and 2,4-d can promote the smooth rooting of some plants (such as tung oil, apple, pear, plum and apricot), and the concentration is generally10 ~100 mg/L.
2. Promote results. Spraying tomato flower clusters with 2,4-D solution of 10 mg/L can promote the formation of fruit-setting and seedless fruits.
3. Promote pineapple flowering. Any pineapple plant that has reached the vegetative growth period of 14 months can blossom after 2 months if it is treated with 5 ~ 10 mg/L NAA or 2,4-D in any month of the year.
4. Stop organs from falling off. Applying 1 0mg/l NAA or1mg/l 2,4-d can keep cotton buds and bolls.
5. Inhibit flower bud differentiation and delay flowering. The first flower bud appeared when spraying 0.0 1 mg/L of 2,4-d chrysanthemum. The chrysanthemum buds sprayed with 0.1mg/l 2,4-d were swollen and transparent in color. Spraying chrysanthemum flower buds with 5 mg/L 2,4-D, the flower buds are still small; The chrysanthemums in the control group are in full bloom.
Spraying rooting plants with 250 mg/L IBA can prolong the flowering period by 2 weeks.
Spraying 50 mg/L NAA on the abscission layer in bud stage can prolong the flowering period of potted Phyllanthus urinaria by 20 days.
6. inhibit fruit ripening. Spraying10 mg/l 2,4-d on potted citrus in bud stage or young fruit stage can prolong the fruit-setting time.
Preparation method of aqueous solution, powder and lanolin ointment containing auxin analogues
1. aqueous solution (taking NAA as an example)
NAA is a colorless powder with a purity of 99% to 80%. Insoluble in cold water, soluble in alcohol, acetic acid and boiling water. How much NAA powder with a certain purity is needed to prepare a certain concentration of liquid medicine can be calculated by the following formula:
Original drug content × original drug dosage (mg)= used concentration (mg/L)/ 1 000× used liquid medicine dosage (mL). For example, when preparing 1000 mg/L 100 mL NAA mother liquor, first calculate how much 99% NAA powder is needed: 99% × x = 1 000/ 1 000× 100. Then 99% NAA powder of 10 1mg is weighed, dissolved in a small amount of 95% ethanol solution by volume, and diluted to 100mL with distilled water to obtain 1000 mg/L NAA mother liquor.
NAA mother liquor can be prepared into NAA solutions with different concentrations. If 40 mg/L NAA solution is prepared, 4 mLNAA mother liquor can be absorbed and diluted to 100mL with distilled water.
Step 2 powder
Firstly, the medicine is dissolved in 95% alcohol solution by volume, and then the prepared alcohol solution is evenly stirred in inert powder (such as talcum powder), and heated properly until the alcohol is completely volatilized.
3. Lanolin ointment
Firstly, the drug is prepared into a certain concentration of aqueous solution, and then mixed with melted lanolin evenly. For example, when preparing 1500 mg/L NAA lanolin ointment, first weigh 1.5 gNAA, dissolve it in 1 mL 95% ethanol solution, then pour it into a big beaker, add distilled water to 1000 mL, and heat and stir until it is completely dissolved. If the volume decreases due to heating, it should be replenished to 65400 ml. Take 500 g lanolin, put it into a beaker of 1000 mL, heat it slightly to melt it, then take 250mL 1500 mg/L NAA solution, inject it into the melted lanolin, and stir it evenly to get 1500mg/L NAA lanolin ointment.
Use of several auxin analogue preparations
1. Spraying, such as spraying flowers and fruits with 2,4-D aqueous solution.
2. Soak, such as soaking the base of the cuttings with NAA aqueous solution.
3. Dip in NAA powder, such as the base of cuttings.
4. If NAA lanolin ointment is applied to the treated parts (such as stems), it is best to gently wrap it with cotton.
An experimental design example of the effect of auxin analogues on plant growth and development
1. Experimental topic: Effects of IAA on seed germination and seedling growth.
2. Experimental principle: IAA can promote seed germination and seedling growth.
3. Objective requirements: (1) Learn how to design and observe the effects of NAA on seed germination and seedling growth.
(2) Observe and analyze the phenomena in the experiment and draw appropriate conclusions.
4. Materials and utensils: seeds (such as radish seeds), test tubes, straws, Petri dishes, filter paper and IAA solution.
5. Experimental hypothesis: A certain concentration of IAA solution can promote seed germination and seedling growth.
6. It is expected that seeds treated with different concentrations of IAA solution will have different germination and seedling growth after 1 week.
7. Method steps:
(1) IAA with concentrations of 1000 mg/L, 10 mg/L, 0. 1 mg/L, 1 μg/L and 0.0 1 μg/L, respectively.
(2) Take 6 test tubes and number them. Add 5 mL IAA solution with different concentrations to test tube 1 ~ 5, and 5 mL distilled water to test tube 6.
(3) Put 20 seeds into 6 test tubes.
(4) taking out the seeds after 24 hours. Take 6 Petri dishes (No.1 ~ 6), each Petri dish is padded with filter paper in advance,No. 1 ~ 5 is soaked in IAA solution with different concentrations (the serial number should correspond to the test tube number), and No.6 Petri dish filter paper is soaked in distilled water. Put the seeds from test tube 1 ~ 6 into the corresponding Petri dish 1 ~ 6 and put them evenly. Cover the Petri dish and put it in the dark.
(5) observation and statistics. 1 week, observe, measure and count.
8. Experimental records:
9. Experimental results and conclusions:
Analysis of (1) experimental results
① Reliability of analysis data.
② Draw a functional diagram according to the obtained data.
③ According to the function diagram, the relationship between the germination rate of radish seeds, the growth status (length) of young roots and hypocotyls and IAA concentration was analyzed.
④ Find out the best IAA solution concentration to promote radish seed germination and seedling growth.
(2) Derivation conclusion According to the analysis of the experimental results, the corresponding conclusions are drawn.
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The research project investigates genetic diseases in the population.
academic goal
1. Learn the basic methods of investigating and counting human genetic diseases.
2. Understand the incidence of some human genetic diseases through investigation.
3. Cultivate the ability to get in touch with society and get information directly from society.
Second, teaching suggestions
Teachers should pay attention to the following points when guiding students to study this subject.
1. The organizational form of the project research, and the research is conducted in groups. The composition of each group should be voluntary and the number of people should not be too large.
2. Before the investigation and study, each group is required to determine the topic according to the local actual situation and formulate a feasible investigation plan, including the purpose, method, division of labor, completion time, report and communication form, etc. In addition, teachers must do a good job in students' ideological work, so that students can complete the research task of this topic with a scientific attitude and have no worries; At the same time, students should be educated not to have any disrespect or incorrect views on people (or classmates) with certain genetic diseases.
3. Before the investigation, the teacher should explain the matters needing attention in the investigation to the students.
(1) When investigating, ask questions in detail and record them truthfully.
(2) Don't repeat the survey, so as not to affect the statistical results.
(3) When investigating a family, it is necessary to write clearly the blood relationship between the members under investigation, and indicate the gender.
4. After the social survey, teachers should guide students to analyze the survey results.
(1) It is necessary to count the incidence of a certain genetic disease in the population.
(2) If possible, it is best to make a detailed analysis of a typical family to explore the genetic mode and types of genetic diseases under investigation.
If possible, it will be more practical and effective to conduct a joint investigation with the local medical insurance department.
3. Reference materials
Common monogenic genetic diseases and polygenic genetic diseases
Polygenic genetic diseases-cleft lip, various congenital heart diseases
Investigation example
1. Objective To understand the incidence of red-green color blindness in middle school students.
2. The subjects of investigation are Grade Three students of Tianjin No.31 Middle School, Grade 98 Grade Two students of Tianjin No.1 H9 Middle School and Grade 99 Grade Three students.
3. Investigation Methods The biology teachers and clinical teachers of our school jointly conducted a survey and conducted a red-green blind examination on the students one by one.
4. Results of the survey
(1) A questionnaire survey on red and green color blindness among some junior middle school students in two middle schools in Tianjin.
(2) Investigation on the family hereditary disease history of two color-blind boys.
Student A: Mom and Dad, grandparents and grandparents are all normal, and grandma is color blind.
Student B: Dad, grandpa, grandma and grandma are all normal, while mom and grandpa are color blind.
5. Analysis of survey results
(1) Incidence of red-green color blindness
There were 2 747 people in the survey, including 38 color-blind patients (male 37, female 1 person), and the incidence of red-green color blindness was 1.38%. The incidence of red-green blindness in men is 1.35%, and that in women is 0.03%. Both of them are lower than the incidence of red-green color blindness in China.
(2) The ratio of male to female who are red and green blind.
Male: female: 135:345: 1, which is also lower than the ratio of red, green and blind men and women in China's social population (14: 1).
(3) Through the investigation of the family history of two boys, it is known that the heredity of red-green color blindness accords with the genetic characteristics of the disease.
6. Conclusion There are more men than women with red-green color blindness in China.
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This research project investigates the effects of environmental pollution on biology.
First, the teaching purpose
1. Understand the adverse effects of environmental pollution on organisms through investigation.
2. Learn the basic methods of investigating the impact of environmental pollution on organisms.
Second, teaching suggestions
Teachers should pay attention to the following points when guiding students to carry out research.
1. Before the project research begins, the teacher should divide the students into several groups, or the students voluntarily form several groups, and the group leader is responsible for the project research work of this group.
2. Teachers should guide students to choose appropriate survey topics and determine specific survey methods according to local conditions and the actual situation of students in our school. Investigation methods can be field observation, social investigation, literature investigation, or a combination of the three, or a combination of visiting local environmental protection departments and consulting information. Urban middle schools and rural middle schools can focus on choosing survey methods. For example, students living in cities or densely populated areas can pay attention to the adverse effects of pollutants (such as domestic sewage, kitchen and coal-fired waste gas, domestic garbage and noise) on human beings; Students living in rural areas can focus on the adverse effects of water pollution and soil pollution on crops. If we are investigating the adverse effects of environmental pollution on organisms, we can generally use field observation to obtain first-hand information. When observing, students should be instructed to carefully observe the changes in some parts of the body and the abnormal physiological reactions after pollution.
3. Because environmental pollution involves a wide range, teachers must remind students that the topic of investigation should not be too big when guiding students to determine the topic. It is advisable for each group to investigate on a topic (or content), and it is more ideal if the investigation topics between groups can be staggered.
Teachers should guide students to make a good investigation plan. Survey plans generally include survey topics, survey methods and survey results. If the investigation is conducted by field observation, it shall also include the investigation time, investigation route, result analysis and conclusion.
Teachers can provide students with some reference materials (see "reference materials") or guide students where to consult materials (such as library, Internet, etc.). ) For students who use literature survey.
6. For students who study by on-the-spot observation, teachers should guide students to start with the specific symptoms of a biological pollution, make detailed observation, and then investigate the source of pollutants (pollution sources). If there are multiple pollution sources, it is necessary to further find out the size and distance of each pollution source and finally determine the main pollution source. Teachers should remind students to take photos or videos if possible during the investigation and observation.
7. After the investigation, teachers should guide students to sort out and process the collected data, complete the investigation report in groups, and communicate in class in time. The investigation report can be in the form of written report, graphic combination, photo explanation, playing self-made video, etc.
8. If the research group adopts the field observation method, the teacher should instruct the students to add a "proposal on prevention and control of environmental pollution" in the report for the reference of relevant departments.
Third, reference materials.
Example of field observation method
1. the research topic investigates the harm of thermal radiation and smoke from coal stoves to street trees in road catering industry.
2. Objective To investigate the harm of street catering industry to street trees.
3. Investigation methods Field investigation and observation.
4. The investigation time was1June 3 to June 7, 1996.
5. The investigation site is in the middle of a farmer's market in Nankai District, Tianjin.
6. Results of the survey
(1) Survey Batch Overview
The middle section of the farmer's market is 540 m long, and the roadside trees on both sides of the road are Fraxinus mandshurica, *** 156. There are 2 restaurants 12 in the south side of the road and breakfast department and 9 restaurants in the north side of the road, totaling 2 1 home. The pollution source is the coal stoves in restaurants and breakfasts, and its pollutants are mainly thermal radiation and smoke.
(2) Observation records
Record the observed phenomena in the table below.
3) results
① The harm degree of pollutants discharged by different catering departments to street trees.
Harm of pollutants discharged in front of seven places to street trees: 6 light 1 heavy (tree death).
13 Harm of pollutants discharged from restaurants to street trees: light 3, heavy 10 (trees die or partially die).
1 The pollutants discharged by the roast duck restaurant are harmful to street trees: lighter.
(2) The relationship between pollutant discharge and street trees.
The catering department in the south of Lunan is more than that in the north, and the pollutant emission in the south is more than that in the north. The damage degree of street trees in the south is obviously higher than that in the north.
③ The damage degree of street trees is inversely proportional to the distance between street trees and chimneys.
④ Damage rate of street trees. 156 Fraxinus mandshurica, 39 trees were damaged, and the damage rate was 25%.
7. Analysis of survey results
(1) Street trees around breakfast and roast duck restaurants are less damaged than those around restaurants. The reason is that the breakfast department and roast duck restaurant have short business hours, short heat radiation time and small pollutant discharge; However, restaurants have long business hours, long heat radiation time and many pollutants.
(2) The street trees far away from the chimney are slightly damaged, and the street trees near or above the chimney are seriously damaged, indicating that the harm of coal stoves to street trees is mainly caused by thermal radiation. Thermal radiation will scorch and kill the branches and leaves, and the blackening of the branches and leaves is caused by the smoke emitted by the coal stove.
8. Conclusion
Coal stoves (pollution sources) in restaurants on both sides of the road, their thermal radiation and smoke (pollutants) seriously harm street trees, ranging from black branches and leaves to technical death.
9. Recommendation
It is suggested that the relevant departments explicitly prohibit the operation of catering industry next to street trees, ban the catering department that has already opened, educate the parties and impose a fine, and replant street trees.