Model essay on the review draft of biology teaching plan in senior high school 1
Notes on meiosis
First of all, talk about textbooks.
1. The position and function of teaching materials
Meiosis is the second part of the first section of the third chapter of senior high school biology. This part is not only the key content of the third chapter, but also one of the key contents of the book. It is based on the knowledge of cytology, chromosomes, mitosis and reproductive species. Through learning, students can fully understand the types, essence and significance of cell division, and lay a cytological foundation for future learning about genetic variation and biological evolution.
2. Teaching objectives
(1) Knowledge Objective: To master the concept of meiosis and the process of sperm formation; Understand the meaning of meiosis and fertilization.
(2) Ability goal: To cultivate students' ability to read and draw pictures, as well as to compare, analyze and summarize by observing the behavior changes of chromosomes during meiosis.
(3) The goal of moral education: By studying the significance of meiosis and fertilization, we can deepen our understanding of the changing law of things themselves and cultivate the viewpoint of unity of opposites and development and change.
3. Teaching emphases, difficulties and determination basis.
(1) Teaching emphasis: the concept and process of meiosis. This is the basis of germ cell formation, heredity, variation and cytology.
(2) Teaching difficulties: the concepts of homologous chromosomes and tetrads and the changing rules of chromosome behavior, in which the changing rules of chromosome behavior are both difficult and important. Beginners lack perceptual knowledge about this and it is difficult to grasp the essence.
4. Teaching material processing
According to the difficulties of the textbook, the actual situation of students and the characteristics of multimedia courseware to transmit information, I arranged two class hours for this part. The first lesson is to learn the concept of meiosis, the process of sperm formation, and the significance of meiosis and fertilization. In the second class, we learn the process of egg formation and compare the similarities and differences between meiosis and mitosis. This paper mainly explains the teaching method and process of the first class.
Second, teaching methods
Bruner believes that knowledge acquisition is an active process, and learners should not be passive recipients of information, but active participants in knowledge acquisition. ? In classroom teaching, students should be properly guided to master knowledge through their own learning under the guidance of teachers, so as to achieve the organic combination of guidance and learning, give full play to students' enthusiasm, initiative and creativity, cultivate students' learning ability and improve teaching efficiency.
1. Preview before class: Introduction.
Reading instruction, aiming at cultivating students? Reading, thinking, asking questions? Study habits. Reading is an important source for students to acquire knowledge. The famous educator Suhomlinski once said: Who is not good at reading and who is not good at thinking? . According to the cognitive objectives of the syllabus, teachers carefully design questions from the students' reality, turn the teaching objectives into targeted, enlightening, exploratory and interesting thinking questions, attract students' attention and guide reading. Through preview, students can understand the main contents and important concepts of this class, which lays a good foundation for this class. At the same time, it is also a good opportunity for teachers to create opportunities for students to actively participate in teaching activities, and also cultivates students' analytical and comprehensive abilities.
(B) classroom lead-in: guiding thinking and inspiring learning.
Teachers make use of students' existing biological knowledge, carefully design leads, and are good at creating problem situations, triggering new problems and inducing thinking into new courses. Bright creativity can inspire people, open the door of thinking, stimulate students' desire for knowledge and enter the learning role with high enthusiasm. At this time, students' psychology is in a state of active excitement, which is convenient for acquiring knowledge and cultivating ability.
(3) Classroom teaching: Guidance and discussion in classroom teaching combined with multimedia teaching methods, appropriate use of guidance and discussion. Guiding method is a method to guide students to learn to read, observe, summarize and create ideas. ? It is better to teach people to fish than to teach people to fish? . Guiding discussion is to design targeted and thoughtful questions under the guidance of teachers, organize students to discuss or be recommended by each group to speak. If there are any mistakes or incompleteness, let other students actively revise and supplement, and finally the teacher will summarize and explain. Make the finishing point? The role of the classroom is full of vitality. Through inspiration, observation, comparison and discussion, teachers enable students to correct their wrong ideas and move from perceptual knowledge to rational knowledge, so as to eliminate the false and retain the true and obtain scientific conclusions. In this process, teachers should encourage students to speak actively, ask questions boldly, express their opinions, and learn knowledge in a lively and harmonious atmosphere, so that teachers' guidance and students' learning are in harmony. Through the guidance of learning method, students learn the skills of accepting new knowledge and improve their learning ability. (d) formative testing: guided training
Pass? Tour guide training? Grasping the feedback of students' learning situation in time is an indispensable link to produce good teaching effect. Teachers carefully draw up typical and enlightening questions that meet the requirements of the syllabus, with moderate difficulty and reasonable gradient, and train students to solve problems in the form of answering and discussing. Its function is to make students think, express and practice with pen, so as to achieve the purpose of consolidation, deepening, broadening and application, and to make students draw inferences from others and correct and compensate in time according to the detection and feedback information.
Third, study law.
Combining the characteristics and teaching methods of this textbook, students can carry out learning activities by reading, thinking, observing and discussing in combination with teachers' knowledge. In order not to make the teacher's guiding activities fail, in teaching, teachers should take the lead and students as the main body, so that students can move their eyes, do things, speak and think, and the learning process and cognitive process of students should be unified as a whole.
Fourth, the specific teaching process.
Divided into two parts
First, create a situation and raise new questions. (1) What is sexual reproduction? (2) What is the main mode of mitosis? Take humans for example. If human chromosomes will be reproduced from generation to generation, according to this calculation, there will be 46 somatic cells in the 30th generation of Confucius' grandson? 230 chromosomes, but this is not the case. There are 46 chromosomes in the somatic cells of the 30th generation grandson of Confucius. Why? By suspecting this contradiction, we can stimulate students' curiosity, firmly grasp students' attention and improve their learning enthusiasm. After that, demonstrate the process of egg reproduction, that is, fertilization, and remind students to pay attention to the chromosome composition in fertilized eggs. In order to further observe the characteristics of chromosomes in fertilized eggs, an animation was designed to simulate the combination process of sperm and eggs. In this way, students can clearly see from the picture that half of the chromosomes in a fertilized egg come from sperm and half from egg cells, and the size and shape of every two chromosomes are similar, which leads to the concept of homologous chromosomes. In order to further illustrate the characteristics of homologous chromosomes, we insert the chromosome map of human somatic cells and finally get a complete concept. Homologous chromosome is the focus and breakthrough point of this topic. In the teaching arrangement, describing the concept of homologous chromosomes in advance is to disperse the difficulties and lay the foundation for discussing synapses and tetrads later. Because the chromosomes of sperm and egg cells are only half of fertilized eggs, that is, somatic cells, it naturally leads to the problem of how sperm and egg cells are produced. Let the students discuss first, and then introduce the concept of meiosis. It also explains several problems that should be paid attention to in learning this concept, including: meiosis naturally wants to know the specific process of meiosis, and enters the second part, taking the formation process of sperm as the second part: the formation process of sperm.
Part II: The process of sperm formation.
First of all, use the method of reading guide to let students study with a few thinking questions. Considerations include:? Where does sperm form? What are the cell names of different stages of sperm formation? What are synapses and tetrads? When did subtraction happen? For the convenience of narration, and to explain the randomness of chromosome separation later, the chromosomes in the cell are represented by four. At the same time, in order to prevent students from being dazzled and distracted, the whole splitting process appears one by one.
When talking about spermatogonia, we should not only point out that it comes from testis, but also point out that its chromosome number is the chromosome number of somatic cells. When spermatogonia form primary spermatocytes, it should be emphasized that chromosomes replicate in this period, that is to say, in synapse, each chromosome already contains two chromatids, but it can't be seen because the chromosomes are in chromatin state at this period, so as to avoid students mistakenly thinking that replication is carried out in tetrad period. In the tetrad period, in addition to emphasizing the concept, in order to prevent individual students from mistaking the four chromosomes in the whole cell for a tetrad, first ask: How many tetrads are there in the picture? Then flash one of the tetralogy to deepen the impression. Finally, the tetrads are summarized, and it is pointed out that the number of tetrads is the logarithm of homologous chromosomes. This treatment has made a good breakthrough? Four times? This teaching difficulty. In the late stage of division, first show that one homologous chromosome is separated to form two daughter cells, and then ask students to discuss whether the homologous chromosome can be separated again. After discussion, a separation diagram appeared in the later stage, indicating that chromosomes have certain independence, and which pole the homologous chromosomes move to is random, that is, different pairs of chromosomes may be freely combined. Studying genetics for the future? Separation phenomenon and the Law of Free Association? Lay a cytological foundation. The process of meiosis is similar to mitosis, which is easy for students to master, but two points should also be emphasized:? Split? And then what? Equal number? . ? Split? Namely centromere division and sister chromatid separation; ? Equal number? That is, the number of chromosomes is no longer half. As for the process of the second meiosis, especially the picture comparison between the late mitosis and the late meiosis, let the students see the difference clearly through the pictures, that is? Does it contain homologous chromosomes? This question further illustrates the essence of meiosis. Then the whole process of meiosis is displayed in full screen, with two purposes: one is to summarize the essence of meiosis, and the other is to review the names of cells in each division period on the blackboard. On the basis of the above study, in order to let students better grasp the changes of chromosome behavior, a continuous animation process was played in the form of sperm. Finally, summarize the significance of meiosis and fertilization, let students discuss it first, and then the teacher will supplement it, so that students can understand its significance and cultivate their ability of induction and summary. Finally, it is pointed out that all these are of sexual reproduction significance, which not only connects the content of last class, but also designs two classroom exercises to strengthen students' understanding and application of what they have learned and cultivate students' ability to analyze and solve problems. The first one examines students' mastery of the law of chromosome number change, and the second one examines students' mastery of homologous chromosomes and tetrads, and feedback the teaching effect in time through two exercises.
Five, blackboard writing is as follows:
Spermatogenesis:
Sperm, primary spermatocyte, secondary spermatocyte, sperm cell, sperm cell
(copy) (first meiosis) (second meiosis) (deformation)
Model essay on the evaluation draft of senior high school biology teaching plan II
Using multimedia technology to optimize biology classroom teaching? An Example of Gene-Directed Synthesis Teaching in protein
Text/Li Qixian
"Gene Directs the Synthesis of protein" is the beginning of the fourth chapter "Gene Expression" of the second compulsory course "Inheritance and Evolution" in senior high school biology education edition. It uses multimedia technology to simulate teaching, intuitively shows the process of transcription and translation, makes this content intuitive, concrete and vivid, and deepens understanding through cooperative inquiry practice, in pursuit of maximizing classroom effect.
First, guide the class? Guess arouses curiosity.
Guidance is the beginning of the whole teaching process. First, the teacher plays a clip from Jurassic Park to stimulate students' interest. After reading it, the question is: in real life, can you really resurrect dinosaurs with DNA molecules that have extinct dinosaurs? Create a new problem: if dinosaurs can be resurrected with dinosaur DNA, what do you think is the main problem to be solved? Introduction: protein is the embodiment of traits, and the synthesis of protein is controlled by genes. So, how do genes guide the synthesis of protein? Leading to the theme ── Gene-directed protein synthesis.
Second, independent inquiry, building a knowledge system
1. Ask questions and think, draw out mRNA, compare DNA and RNA, and pave the way for transcription learning.
Question thinking: Where does eukaryotic DNA mainly exist? Where was protein synthesized?
Guided inquiry: The teacher first emphasized that the DNA in the nucleus cannot leave the nucleus through the nuclear pore, and the place where protein is synthesized is the ribosome in the cytoplasm. The question arises: How does the DNA in the nucleus guide the synthesis of protein in the cytoplasm?
2. Break through the difficulties in the transcription process.
Question thinking: How the genetic information on DNA is transmitted to mRNA, which leads to the learning of transcription process.
First of all, the courseware shows the animation process of transcribing. Remind students to pay attention to the place where the transcription process takes place, the conditions and products needed. Secondly, arrange students to read the copied content in the textbook. Third, students build independently? Transcription? Concept, thinking and summarizing the relevant knowledge of transcription process, and completing 8 knowledge points about transcription, which the teacher emphasized and supplemented. Finally, the courseware shows the animation process of transcribing again.
3. Understand the related knowledge of codons and anti-codons to pave the way for translation learning.
Exploring Codon: By transcribing the genetic information of DNA into mRNA, how does mRNA translate its base sequence into protein's amino acid sequence? To understand this process, we must first look for the corresponding relationship between bases and amino acids. What is the relationship between bases and amino acids?
The concept of codon is put forward, and the courseware shows the codon table. Teachers and students watch the summary of codon table: except for three stop codons, one codon corresponds to one amino acid, and one amino acid may correspond to multiple codons. Codons are common to all organisms, indicating that there is a certain genetic relationship between organisms.
Explore new content: how are those amino acids free in cytoplasm transported to ribosomes? Lead out tRNA and demonstrate the structure of tRNA with courseware.
Teacher-student summary: the structure, function and types of tRNA.
4. Break through the key points and difficulties in this translation process.
Continue to wonder: How does tRNA transport free amino acids in cytoplasm to protein? Assembling ribosomes on machines leads to the learning of translation process.
(1) courseware shows the animation process of translation. Remind students to pay attention to the place where the translation process takes place, the conditions needed and the products. (2) Arrange students to read the translated content in the textbook. (3) Students' self-construction? Translation? Concept, thinking and summarizing the relevant knowledge of translation process, and completing 8 knowledge points about translation, which the teacher emphasized and supplemented. (4) The courseware shows the animation process of translation again. At this time, students have understood the process of translation in their minds, and playing back the animation process of translation has deepened their understanding and memory of knowledge.
5. The courseware shows the whole process of protein's gene guidance (transcription and translation) and DNA replication (Chapter 3).
Students watch the process of transcription, translation and DNA replication in the previous chapter. They first complete the form, compare, understand and remember the important and difficult knowledge, and then complete the exercises to improve their knowledge application ability.
Third, expand sublimation and independently derive formulas.
The problem escalates: the genetic information of DNA is transmitted to RNA through transcription, and then RNA is translated into protein with a certain amino acid sequence. What is the quantitative relationship between the base number of DNA, the base number of RNA and the number of amino acids in this process?
Students independently carry out simple derivation, thus obtaining the number of bases of DNA: ∶RNA: amino acid = 6: 3: 1, and applying this knowledge point, combining teaching with practice to improve classroom efficiency.
Fourth, expand after class and cultivate innovative spirit.
Echo before and after: can dinosaurs be revived by using dinosaur DNA?
Courseware presentation: links to websites related to this part of knowledge.
Provide students with links to websites related to this knowledge, so that students can extend their study after class and promote their new learning motivation.
There is no definite teaching method, and there is no unique and absolutely effective teaching mode in teaching. The vitality of teaching mode lies in teachers' continuous learning and innovation. I hope to create more and better modern biology teaching models suitable for quality education.
Model essay on the review of senior high school biology teaching plans 3
Teaching design of sugar, fat and protein detection in biological tissues
Author/Sun
This lesson is an experiment in the second chapter 1 section of the standard experimental textbook "Biology Required Course 1 Molecules and Cells" for senior high schools.
I. teaching material analysis
1. Curriculum standard requirements
This experiment is a confirmatory experiment in the transitional textbook, but an exploratory experiment focusing on cultivating students' inquiry consciousness in the curriculum standard textbook. It is the first experiment in the textbook that can guide students to make a preliminary inquiry. Therefore, doing this experiment well not only plays an important role in cultivating students' inquiry ability, but also enables students to experience inquiry thinking and master the general methods of scientific inquiry.
2. Teaching material design concept
In the textbook of curriculum standard, this experiment is arranged before studying protein, sugar and fat. On the one hand, it aims to lay a perceptual knowledge foundation for the next step of learning various organic substances; On the other hand, paying attention to students' choice of materials, expectation of test results and design of experimental scheme will help to cultivate students' experimental inquiry ability and lay the foundation for the smooth development of exploratory experiments in the following chapters. This experiment is an exploratory experiment for all students, trying to make every student gain and improve on the original level.
Second, the teaching objectives and difficulties
1. Teaching objectives
(1) Knowledge Objective: To explain that specific chemical reagents can cause specific color reactions of corresponding organic compounds in biological tissues; This paper briefly introduces the general method of experimental inquiry, which mainly designs experiments according to the selected experimental materials and makes the expected experimental results.
(2) Emotional attitude and values goal: Participate in cooperative learning and form a rigorous and serious scientific attitude that dares to question. Operate the experiment according to the experimental operation rules and develop good experimental habits.
(3) Ability goal: Try to detect reducing sugar, fat, protein and starch in biological tissues with chemical reagents.
2. Teaching emphases and difficulties
Emphasis: Principles and methods of detecting sugar, fat and protein in biological tissues.
Difficulties: there are many materials used in the experiment, many kinds of reagents and methods of use, and the classroom capacity is large.
Breakthrough: facing all students, make full preparations, including materials and instruments preparation, students' emotional and knowledge preparation; Give full play to the role of class leaders in assisting management in class and organize teaching in a reasonable and orderly manner.
Thirdly, the analysis of learning situation.
High school students' thinking level and learning ability have developed to a higher stage, and they are willing and able to carry out independent inquiry learning. The content of the experiment is related to daily diet and pays attention to the connection with real life. Students are likely to be interested in learning and set up different levels of inquiry to meet the needs of students with different intelligence levels, personalities, interests and ways of thinking. However, there are many materials and reagents, and there are many details of standardized operation, so cooperative learning is particularly important.
Fourth, teaching rules.
Teaching methods: organize and guide, and pay attention to the re-exploration of generative problems.
Learning methods: task-driven, independent inquiry, cooperative learning, sharing and communication.
Verb (abbreviation of verb) teaching program
Sixth, teaching reflection.
What is this experimental lesson based on? Autonomy, inquiry, cooperation and honesty? It is the four basic dimensions of classroom teaching, facing all students, paying attention to cultivating students' biological science literacy, paying attention to the connection between scientific method education and real life, giving full play to the auxiliary role of the team leader in experimental operation, managing and standardizing the classroom, dividing labor and cooperation, and improving classroom efficiency. Through students' self-evaluation and mutual evaluation, it is found that the difference of reagent dosage will affect the inference of experimental results, and unified and appropriate standards should be mastered in the experiment. In addition, to carry out exploratory experiments, students need to be given enough time to think and discuss, and the experimental results need to be carefully analyzed, so as to effectively improve students' various abilities. Therefore, teachers should carefully design the teaching process, make all kinds of preparations and presuppositions in advance, and arrange the teaching time reasonably in order to achieve the ideal teaching effect.
Seven, blackboard design
Detection of sugar, fat and protein in biological tissues.
1. experimental principle
Reducing sugar+firing reagent? (water heating) brick red precipitate
Fat+Sudan ⅳ? red
Protein+biuret reagent? purple
Starch+iodine solution? blue
2. Experimental materials
Unknown tissue sample solution (apple juice, potato homogenate, egg white tissue sample solution, peanut seed homogenate)
3. Experimental procedures
(1) grouping experiment to identify unknown sample solution.
(2) Fill in the experimental form and record the experimental results.
(3) draw a conclusion
(4) Evaluation communication
4. Expand the scope of investigation
(1) Is there a difference in reducing sugar between Sprite and Xylitol?
(2) What are the main differences between the nutritional components of rice flour and milk powder?