Teaching design of biology teaching plan in senior high school
Fluid mosaic model of biofilm
First, the teaching objectives
Knowledge and skills
Briefly describe the structure of biofilm
Process and method
Taking the course of exploring the molecular structure of cell membrane as the main line, the brain is used to analyze experimental phenomena, draw experimental conclusions, establish models and experience scientific experimental ideas and methods. Try to ask questions and make assumptions.
Emotional attitude
To explore the role of the progress of experimental technology in the establishment of biofilm model; This paper discusses how the process of establishing biofilm model embodies the view that structure and function are compatible.
Two. Textbook analysis
In this section, the exploration process of biofilm structure is introduced in more space, and two reflections and discussions are arranged, so that students can understand the context of these knowledge while understanding the membrane structure, and realize that hypotheses can be put forward through reasoning and analysis of phenomena, which still need observation and experiment to verify. With the improvement of technical means, new evidence is constantly found, and the original viewpoints or theories will be constantly revised and improved, and the basic methods of biofilm model construction are summarized. In addition, we should focus on understanding and mastering the fluid mosaic model of biofilm, and learn to use this model to explain the corresponding physiological phenomena.
Three. Analysis of academic situation
High school students have a certain ability of observation and cognition, but the motivation of exploring questions mainly comes from the degree of curiosity and interest in related issues, and the purpose is not very clear. Therefore, the teacher's thinking orientation is very important. This lesson uses the experimental data of the history of science to design questions that students should explore. Let students conduct classroom inquiry activities according to materials and questions under the guidance of questions. The design of questions is in-depth at different levels, reaching a certain depth according to students' thinking level and ability, so that students can smoothly transition from perceptual knowledge to rational knowledge.
Four, teaching difficulties:
Focus: Fluid mosaic model of biofilm.
Difficulties: How does the process of establishing biofilm model reflect the viewpoint of compatibility between structure and function?
Teaching process of verbs (abbreviation of verb)
course content
1, launch new courses.
2. Describe the phospholipid arrangement of the membrane.
3. Electron microscope photo demonstration
4. Demonstrate the experimental process
5. Guide the construction of the model
Summarize the content
Teachers' activities
This paper introduces Irvington's experiment at the end of 19. "Cell membranes have different permeability to different substances, and fat-soluble substances are more likely to enter cells through cell membranes than fat-insoluble substances." And put forward this question: "the composition of cell membrane.
What's in it? What is the basis of your inference? "Guide students to analyze and answer.
"Phospholipids are molecules composed of glycerol, fatty acids and phosphoric acid. The head is hydrophilic and the tail is hydrophobic. And gradually put forward the question: how will phospholipid molecules be arranged on the water surface (air-water interface)? How are the phospholipid molecules "spherical" arranged in water? Guide students to discuss and analyze the most possible arrangement of phospholipid molecules in biofilm.
1925, Dutch scientists used organic solvents to extract the lipid components of human erythrocyte membrane and "spread it on the water". It was measured that the spread area of membrane lipid was twice the surface area of the cell. Why is this? Let the students analyze and get the answer.
"If the red blood cells in the data are replaced by oral epithelial cells for experiments, is the area of the monolayer still only twice the surface area of oral epithelial cells? What happens if the human red blood cells in the data are replaced by chicken or skinned prokaryotic cells for experiments? Why?
The projection of Robertson's discovery under the electron microscope and his hypothesis (see the textbook) then inspire: Can this model be questioned according to the differences of different organisms and the compatibility of structure and function?
Some subsequent experimental techniques show that protein particles exist in bilayer lipid. To this end, did you just verify your question? Great! What other distribution states of protein molecules in the membrane can be inferred? Can you chart your ideas?
Play the courseware of "Fusion Experiment of Fluorescent Labeled Mouse Cells and Human Cells", and then ask: This experiment shows that protein molecules in the membrane are in a certain state of motion. So, are all protein molecules in motion? What about lipid molecules? Accordingly, the structural feature of membrane is not summarized as "fluidity", but "fluidity". Can you find out why? Can you give some examples to prove that the membrane has fluidity? Design intention: to cultivate students' good habit of being good at association and careful thinking, stimulate deep exploration and help to understand "membrane fluidity"
Sanger and Nixon proposed a fluid mosaic model in 1972 by modifying the existing model, which was accepted by most people. At this point, students can also imagine the "appearance" of this model, imagine it independently first, and then solve its mystery.
Class summary and practice.
Student activities
Explore the main components of the membrane
Experiencing the experimental process
Think about the experimental results.
Watch the animation
Experience discovery process
Self-construction mode
Sixth, blackboard design
4.2 Fluid Mosaic Model of Biofilm
First, the exploration process
1, phenomenon: fat-soluble substances easily enter the cell membrane.
Conclusion: Its components are fat and protein.
2. Phenomenon: The area of monolayer is twice that of membrane Conclusion: phospholipid bilayer.
3. Phenomenon: dark structure and bright structure
Conclusion: The three-layer structure is static and unified.
4. Phenomenon: protein flows in the hybrid cell membrane.
Conclusion: The molecules on the membrane have fluidity.
Two. Fluid Mosaic Model (Figure)
Teaching design of biology teaching plan in senior high school II
From biosphere to cell
First, the teaching objectives:
For example, 1 says that life activities are based on cells.
2. Talk about the structural level of life system.
3. Recognize that cells are basic life systems.
Second, the difficulties in teaching:
1, cells are the key to basic life systems.
2. The structural level of life system is difficult to talk about.
Third, teaching tools:
multimedia courseware
Fourth, the schedule:
1 class hour
Five, teaching methods:
Heuristic teaching, discussion teaching of seeking common ground while reserving differences, self-study guidance.
Sixth, the teaching process:
(A), the organization of teaching, to stabilize students' mood
(B), the introduction of new courses:
Question: 1. Is a virus a creature?
2. This virus does not have many basic characteristics of extracellular life. How is it copied?
3. In which cells does the coronavirus replicate?
(3) Discussion:
1, browse virus pictures and related materials on PPT:
2. Organize students to think and discuss, and answer questions raised by teachers.
3. Summary: According to the summary, viruses without cell structure can't show life characteristics outside cells, which shows that cells are the basic characteristics of life. Without cells, no part of cells will have the ability to survive independently, and macromolecular substances will not have the characteristics of life. So cells are the basic unit of life activities.
Question: What life activities can cells show? Instruct students to read the materials and have group discussions.
(4) Analysis of cells is the basic feature of life activities. Students teach themselves materials, think and discuss.
Example 1: paramecium can eat, excrete, grow and stress besides division and exercise;
Example 2: Embryonic development, as a bridge between sperm and egg cells, is related to cell growth, division and differentiation;
Example 3: the structural basis of hand-shrinking reaction, emphasizing the coordination and cooperation between differentiated cells;
Cell is the basic unit of life structure and function. A cell can complete all kinds of life activities; Multicellular organisms realize various life functions on the basis of cell life activities; All life activities are inseparable from cells.
(5), the structure of the life system.
1, read quickly and take shorthand on the structural levels of life systems, and ask students to write down these nine levels on the blackboard:
2. Explain several levels of life system in turn, especially the concepts of population, community and ecosystem.
3. Emphasize the difference between single-celled organisms, higher plants and animals.
Summary: The macro structure level of life system is biosphere, and the micro level is cell. All levels can independently complete life activities, but they are interdependent and mutually restricted, and they are closely related and cooperate with each other to form a whole.
Seven. This section outlines:
All living things are inseparable from cells, which are the basic units of biological structure and function.
The structural level of life system: cell → tissue → organ → system → individual → population and community → ecosystem → biosphere.
Eight, teaching reflection:
1, familiar with the content, able to grasp the important and difficult points, clear-cut.
2, can fully mobilize the enthusiasm of students.
Teaching design of biology teaching plan in senior high school III
Energy supply and utilization of cells
First, the teaching content and teaching object analysis
1. Teaching content
A living cell is an open system, which exchanges substances and energy with its surroundings at all times, and uses these substances and energy to maintain its own life activities and carry out metabolism. As a biocatalyst, both substance transformation and energy transformation in cells can not be separated from the catalysis of enzymes. Therefore, it is very important to guide students to master the concept and essence of enzymes and understand the role of enzymes in metabolism. In addition, students have the ability to do science. Guiding students to think scientifically and do experiments actively in class is very beneficial to cultivate students' scientific spirit. Therefore, this course first introduces controlled experiments and controlled variables.
2. Analysis of teaching objects
Students are familiar with pure chemical reactions through the study of chemistry in grade three and grade one, but have limited knowledge of chemical reactions of cells and biocatalysts-enzymes. The chemical reaction of industrial ammonia production is carried out under the catalyst of high temperature and high pressure, while the interior of cells is in a mild state at normal temperature and pressure, and cell metabolism includes a series of chemical reactions. These chemical reactions must be carried out with the participation of biocatalyst-enzyme, so the study of enzyme-related knowledge is introduced.
Second, the teaching objectives
1. Knowledge target
To explore the essence and function of enzymes in living cells, and to explore the efficiency and specificity of enzymes.
2. Ability objectives
① Conduct relevant experiments and explorations, learn to control independent variables, observe and detect the changes of dependent variables, set up control groups, and repeat experiments.
(2) To cultivate the ability of using language to express, and the ability of consulting materials and enjoying information in problem discussion, experimental design and data analysis.
3. Emotional goals
① By reviewing the history of scientists exploring the essence of enzymes, we agree that science is advancing through constant observation, experiment, exploration and debate.
(2) It is agreed that scientists should not only inherit the scientific research achievements of predecessors, but also be good at questioning, be brave in innovation and practice.
Third, teaching methods and teaching means
1. Teaching methods: experiment, group discussion, encouragement and evaluation, comparison and explanation, cartoon pictures,
2. Teaching method: Using multimedia to design the experimental form.
Fourth, the teaching process
Teaching process of verbs (abbreviation of verb)
Teachers' activities
Student activities
Design intent
Ask questions carefully and step by step (5 minutes)
It's almost noon. Everyone must be hungry. Why are you hungry? How is food digested?
[Discussion] Illustrate 1783 Spallanzani's "Eagle and Cage" experiment, and discuss related issues and the originality of the experiment.
[Contrast] What are the conditions for industrial ammonia production?
Do these conditions exist in cells? However, the chemical reactions in cells are still carried out efficiently and orderly. What is the reason?
【 Title 】 The function and essence of enzyme
Stimulate students' interest and let the brain enter the thinking state quickly.
[Group discussion, come to a conclusion]:
Birds' stomachs have not only physical digestion, but also chemical digestion.
Answer:
High temperature, high pressure, catalyst
Speculate:
There are biocatalysts in cells.
Pave the way for introducing new courses.
This experiment is the first time in the study of enzymes. The process of asking questions, experimental scheme, experimental hypothesis, conclusion and inference, and the consciousness of innovative thinking are of great significance to students.
[New lesson] Explore and discuss, lead discussion and dispel doubts (30 minutes)
First, the role of enzymes in cell metabolism (20 minutes)
Guide thinking, design experiments and verify the high efficiency of enzyme.
【 Experimental Principles and Materials 】 We know that hydrogen peroxide can be decomposed into water and oxygen under the catalysis of fe3+. Fresh animal liver grinding fluid contains catalase. If you are given fresh animal liver grinding liquid, hydrogen peroxide, ferric chloride solution and necessary experimental equipment, can you design an experiment?
[Hint 1] Who is the high efficiency of the enzyme?
[Tip 2] How to choose reactants?
[Hint 3] What is the dependent variable?
[Tip 4] What conclusions can be drawn from observing those phenomena?
[Hint 5] Discussion on the expectation and result of the experiment.
Question: Why are enzymes efficient?
[This experiment is a special supplement]
Experiments were designed to verify the specificity of the enzyme.
[Transition] Cell metabolism includes many chemical reactions, which are not only rapid but also orderly, indicating that enzymes are not only efficient but also specific as catalysts.
Tip: How to understand specificity?
We know that papaya juice contains papain, and tender meat powder also contains protease preparation. If papaya juice, tender meat powder, milk, soybean milk, starch solution, iodine solution, phenanthrene reagent and biuret reagent are given, it is necessary to choose appropriate reagents and new experimental equipment. Can you design an experiment to verify the specificity of the enzyme?
[Summary] The high efficiency and specificity of enzyme.
[Student experiment 1]
[Group discussion]
Design experimental scheme
Design tables to record experimental phenomena and results.
Answer: Inorganic catalyst
Thinking: Should inorganic catalysts and enzymes catalyze one respectively? Or catalyze the same substance?
Answer: Decomposition rate of hydrogen peroxide
Answer:
The number of bubbles and their generating speed
Re-ignition of lit sanitary incense
Results: The catalytic efficiency of catalase was higher than that of ferric chloride, which indicated that catalase was efficient.
A: It lowers the activation energy.
The reference materials are cartoon illustrations, combined with text narration and image description.
[Student Experiment 2]
[Group discussion]: It is necessary to show that the enzyme can only catalyze a certain reaction and has no catalytic effect on other reactions.
[Group discussion of experimental scheme]
What kind of enzyme do you choose? What reactants do you choose? How to design a comparison? How to identify the results? Predictive results?
Understand variables, independent variables, dependent variables, irrelevant variables, controlled experiments
Observe the experimental phenomenon and realize the high efficiency of catalase.
Cultivate language expression ability and raise perceptual knowledge to rational knowledge.
Experiment 1 is to catalyze the same substance with two different catalysts. Experiment 2 is to catalyze two different substances with the same enzyme, so that students can understand the idea of designing experiments. How to choose materials? How to design a comparison? So as to strengthen the training of experimental skills.
The teachers deliberately set two small traps. ① Let the students choose protein's identification reagent to consolidate its usage. (2) Rich materials, knowing how to choose according to the needs of experiments, and not being greedy.
Second, the nature of the enzyme (10 minutes)
1. From the perspective of characters.
2. According to the research results.
From observing problems, from problems to guessing, from guessing to experiments, from imperfection to perfection, this is an inevitable step in doing science and an inevitable law of scientific development.
[supplement]
The precursor of (1) tetrahymena has catalytic activity. (2) At present, it has been reported that dna with catalytic activity has been found.
3. Guidance and encouragement
Combining the exploration of the essence of enzyme and the winning process of sumter's 9-year Nobel Prize, this paper discusses the understanding of Marx's sentence.
[Summary] The essence of enzyme
[Read the materials to explore the nature of enzymes]
Complete the first basic question on page 82 of the textbook and understand the logical relationship between the views of several scientists.
Analyze the advantages and disadvantages of each scientist's scientific conclusions.
[Group discussion]
In the process of enzyme discovery, from the physical digestion of the stomach to the chemical digestion of the stomach, protein-digesting substances were extracted from gastric juice, urease crystals were extracted, and it was confirmed that urease was a kind of protein, and protein crystals of various enzymes were extracted. It was pointed out that enzymes catalyzed protein, and a few rna also had biocatalysis, which further improved the concept of enzymes.
[collective speech]
There is no royal road to science.
The bitterness and sweetness of science.
[group summary]
Enzymes are catalytic organic substances produced by living cells, most of which are protein and a few are rna.
Cultivate students' scientific spirit and attitude of inheritance, innovation, seeking truth from facts and bold practice.
Guiding students to analyze this process from two different angles is actually a process of improving students' analytical reasoning ability.
Incentive evaluation: scientific knowledge is not static, but a process of continuous development. Only by seeking up and down can scientific research be endless. You can also be a shining star in the future.
Promote students to actively change their learning methods and cultivate students to actively construct knowledge.
[Explore further after class] (5 minutes)
Please design an experiment to prove that the enzyme is protein according to the following materials:
Experimental materials: 5% naoh solution, 3% cuso4 solution, eggs, water, saliva, small beaker, glass rod, test tube dropper, tweezers and absorbent cotton.
Experimental principle:
Experimental steps:
Experimental conclusion:
Understand the nature of enzymes
Train experimental thinking.
Teaching summary of verb (abbreviation of verb)
As an open life system, cells constantly exchange substances and energy with the surrounding environment, and realize metabolism on this basis. As biocatalyst, enzyme plays a very important role in the efficient and orderly completion of various physiological functions of cells. With the continuous development of science, the exploration of the essence of enzymes is also constantly improving. In recent years, the development of enzyme engineering has brought great vitality to production and life, and this little progress is not only due to bold speculation, but also to scientific and ingenious experimental design. Therefore, students should learn to find and ask questions in daily life, and then solve problems through reasoning and experiments, so that you will have unexpected surprises, and your ability to solve problems and scientific experiments will be greatly improved. I hope the star of science tomorrow is you.
Sixth, teaching reflection.
According to the requirements of curriculum standards, this class advocates inquiry teaching and organizes teaching in the form of group mutual assistance, which can guide students to actively participate in the process of knowledge construction. This course not only makes good use of the experiments in textbooks, but also is good at finding more flexible typical examples from real life, skillfully guiding students to consider problems from different angles, one positive and one negative, reflecting each other, so that students can fully understand what independent variables, dependent variables, irrelevant variables and control experiments are, which is conducive to guiding students to learn to confirm and control variables and cultivating students' scientific inquiry ability. This course uses a large number of encouraging evaluation mechanisms to give full play to students' potential and pay attention to cultivating students' scientific spirit and attitude and values that dare to question, innovate and guess. The disadvantage is that time is tight, so some experiments are left to be operated after class.
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