First, DNA is indirect evidence of genetic material.
1.DNA is mainly located in the chromosome of the nucleus, and there is also a small amount of DNA in mitochondria and chloroplasts, all of which have the autonomy of replication and inheritance.
2. The content of DNA in cells of different developmental stages or tissues of the same organism is basically the same.
3. All factors that induce DNA structural variation can cause genetic mutation of organisms.
4. protein does not have these characteristics.
Second, DNA is the direct evidence of genetic material.
1. bacteriophage infection test
Principle (1): After the T2 phage is infected with bacteria, under the control of its own genetic material, the components of the T2 phage are synthesized by using the substances in the bacteria, thus carrying out mass reproduction.
(2) Process:
① protein and DNA were labeled with 35S and 32P respectively;
(2) infecting bacteria with labeled phage;
(3) When the phage proliferates, the labeled substance is detected.
(3) Conclusion: DNA is a kind of genetic material.
2. Transformation experiment of pneumococcus
Principle (1): S-type bacteria can cause sepsis and death in mice.
(2) In vivo bacterial transformation experiment (in vivo transformation)
Process:
① Mice injected with R-type bacteria → mice do not die;
② injection of S-type bacteria into mice → death of mice;
③ Inject the killed S-type bacteria into mice by heating → the mice will not die;
④ Mice were injected with S-type dead bacteria +R-type live bacteria → the mice died.
Conclusion: S-type bacteria contain "transformation factor", which can transform R-type bacteria into S-type bacteria and kill mice when they enter R-type bacteria.
(3) In vitro bacterial transformation experiment (in vitro transformation)
① Process: S-type bacterial DNA+R-type bacteria +S-type bacteria;
S-type bacterial protein +R-type bacteria R-type bacteria;
S-type bacteria +R-type bacteria polysaccharide in the capsule material of R-type bacteria;
DNA of S-type bacteria deoxyribonuclease +R-type bacteria.
Conclusion: The DNA of S-type bacteria is the substance that causes stable genetic variation of R-type bacteria.
(4) Conclusion: According to experiments (2) and (3), DNA is a genetic material.
Thinking: What is the main genetic material of human beings and organisms with cellular structure?
Tip: mainly DNA.
2. Excellent example of biology teaching plan in senior three.
Teaching objectives
1, knowledge and skills
(1) Understand the principle of water absorption and water loss of cells.
(2) Learn to design experiments initially.
(3) Learn to observe the separation phenomenon of plant cytoplasm wall.
2. Process and method
(1) can summarize problems and laws through charts and experiments;
(2) The principle of cell water absorption and water loss can be used to explain related phenomena in life and production practice.
3. Experience emotional attitudes and values, and establish a scientific world outlook that adapts to the structure and function of organisms and coordinates parts with the whole.
Important and difficult
1, principle of water absorption and water loss of key cells.
2. The principle of water absorption and dehydration of difficult cells and the experimental design of plasma wall separation.
teaching process
Design intent
Introduction of cell water absorption and water loss: small experiment-comparison of soft and hard radish strips
1, radish strips soaked in concentrated salt water;
2. Radish strips are soaked in water;
3. Fresh radish strips.
Overview: Osmotic absorption and osmotic dehydration of cells
Osmosis: diffusion of water molecules through cell membranes. Observe and analyze the reasons for the difference between soft and hard. The ability of culture to analyze problems is questioned 1: how to observe the water absorption and water loss of cells from a microscopic point of view? Thinking guides students to see phenomena through essence.
1. experimental design: water absorption and dehydration experiment of onion epidermal cells.
Material: Questions about onion scales.
2. Why did you choose onions for the experiment? Thinking II. Structural Basis of Permeability Reading and Checking Drawings: Choose the concept of permeability to pave the way for questioning the experimental design.
3. What is the main structure through which water molecules penetrate into or leave cells? Thinking and judgment pave the way for experimental design
Instruments and reagents: microscope, tweezers, glass slide, cover glass, blade, 30% sucrose solution, water Discussion: How to design the experiment summary;
Design experiments, exchange scientific ideas, guide students to form experimental designs, and guide students to operate experiments.
Experimental operation experimental skills practical experiment summary: onion epidermal cells absorb water and lose water video
Plasma wall separation: the separation of plant cell wall and its protoplasm layer.
Separation and recovery of plasma wall: the phenomenon that cells after plasma wall separation return to their original normal shape. Question 4: What are the external conditions related to the experiment that cells absorb water or lose water? Self-induction and summary of thinking society from phenomenon to principle III. Principle When the concentration of external solution is less than that of cell fluid, cells absorb water.
When the concentration of external solution is greater than that of cell fluid, cells lose water. According to the three images seen during the operation, the students summarized and further explored: the concentration of cell fluid in onion skin. Discuss and communicate, expand thinking and consolidate experiments.
3. Excellent example of biology teaching plan in senior three.
I. Knowledge
1, let students know the discovery process.
2. Make students understand the types, colors and absorption spectra of pigments in chloroplasts; Preliminary study on extraction method of photosynthetic pigment and its distribution on filter paper.
3. Master the concept, essence, general reaction formula, specific process, difference, connection and significance of light reaction and dark reaction.
4. Apply what you have learned and understand the relationship between plant cultivation and rational use of light energy.
Second, ability.
1. Through the experiment of extracting and separating chloroplast pigment, the students' laboratory operation skills and the ability to use related instruments and drugs were initially cultivated.
2. By exploring the source of oxygen, the students' experimental design ability is initially cultivated.
3. By analyzing and discussing the specific process of bright reaction and dark reaction, cultivate students' good thinking quality.
Third, feelings, attitudes and values.
1, through students' understanding of the meaning of green plants, enhance students' awareness of protecting the ecological environment.
2. Students discuss how to use the principle to improve crop yield and pay more attention to science, technology and society (STS).
Teaching suggestion
Textbook analysis
This section is one of the key contents of this chapter, because it is of great significance in the metabolism of green plants and the material cycle and energy flow of the whole ecosystem. This section of the textbook mainly tells about the discovery process, chloroplasts and pigments in them (and arranges students to do experiments on the extraction and separation of pigments in chloroplasts), the process, significance, plant cultivation and rational use of light energy. The basic knowledge has been described in the biology textbook of junior high school in compulsory education, and the experiment of making starch from green leaves under light has been arranged. On this basis, this section describes several experiments in the process of discovery from two aspects: product and place. Tell about chloroplasts and pigments in them, so that students can learn to extract and separate chloroplast pigments.
First of all, the textbook shows students the arduous course of human research on this most important physiological process on the earth, and introduces several experiments in the research process, such as: 177 1 year, and British scientist priestley proved that plants can renew the air; 1864, the German scientist Saks proved the experiment of producing starch from green leaves. 1880, German scientist engelmann proved that chloroplast is the place for chloroplast oxygen release experiment; In 1930s, American scientists Rubin and Carmen used isotope labeling to prove that all released oxygen came from water. The purpose of introducing these experiments is to make students understand that experiments are the basic methods to explore biological sciences, so as to cultivate students' scientific attitude of seeking truth from facts and innovative spirit of constantly exploring new knowledge.
Second, the pigment in chloroplast is the focus of this section, and the experiment is the difficulty of this section.
Students must be clear about the types of pigments in chloroplasts and their absorption spectra, the stacking form of lamellar structure of grana, the distribution of pigments on lamella, and the relationship between grana and matrix, so as to deeply understand the light reaction and dark reaction and their relationship.
When the textbook introduces the pigments in chloroplasts, a student experiment is designed, that is, "Extraction and separation of pigments in chloroplasts", which is convenient for students to have a perceptual understanding of chloroplast pigments. This experiment can be used as a verification experiment after teaching chloroplast pigment, and can also be used to explore chloroplast pigment. In addition, the absorption spectrum of chloroplast pigment in the textbook can also be used as an inquiry topic for students to discuss the physiological functions of chloroplast pigment in class.
Third, the process in the textbook is the key content of this section, and it is also the difficulty of this section.
1, the total reaction formula, namely
The location, conditions, raw materials, products and sources of oxygen are summarized, but the reaction formula is not enough to express the specific process. Therefore, the textbook briefly introduces two important processes in the form of charts, namely, light reaction and dark reaction.
2. Photoreaction stage
The light reaction stage in the textbook can be summarized into two aspects: light reaction place and light reaction process.
(1) Photoreaction site: It is carried out on the membrane (thylakoid) with layered structure of chloroplast grana.
(2) Photoreaction process: The essence of photoreaction is photochemical reaction caused by visible light, which can be divided into two aspects:
① Photolysis reaction of water: Through the absorption and transmission of light energy by photosynthetic pigments, under the action of some light energy, water is decomposed into hydrogen and oxygen, oxygen atoms combine to form oxygen and release it, and hydrogen and NADP combine to form NADPH, which is called reducing hydrogen and participates in dark reaction as a reducing agent.
②ATP synthesis reaction: another part of light energy is absorbed by photosynthetic pigments and transferred to ADP, which combines with a phosphoric acid to form ATP, and then the light energy is converted into active chemical energy and stored on high-energy phosphate bonds.
3. Dark reaction stage
The dark reaction stage in textbooks can also be summarized as dark reaction place and dark reaction process.
(1) dark reaction site: in chloroplast matrix.
(2) Dark reaction process: In fact, dark reaction is an enzymatic reaction, which can only be completed under the catalysis of various enzymes, and light has no effect on dark reaction. It mainly includes three steps:
① Fixation of carbon dioxide: A carbon dioxide molecule combines with a five-carbon compound molecule to form two three-carbon compound molecules. The function of this reaction is to activate carbon dioxide molecules with low reactivity.
(2) Reduction of three-carbon compounds: Some three-carbon compounds are reduced by [H] produced by photoreaction under the catalysis of related enzymes. After a series of complex changes, sugar is formed, and some amino acids and fats are also made of.
(3) Regeneration of five-carbon compounds: other three-carbon compounds undergo complex changes to regenerate five-carbon compounds, so that the chemical reaction in the dark reaction stage can continue.
4. The meaning in the textbook can be summarized from the following aspects: it is the source of organic matter in biology; It is the source of energy needed by biological life activities; It can adjust the contents of oxygen and carbon dioxide in the atmosphere; It plays an important role in biological evolution, that is, it makes it possible for anaerobic respiration to evolve into aerobic respiration, and it also creates conditions for aquatic organisms to evolve into terrestrial organisms.
At last, the textbook concludes: "It is the most basic energy and material metabolism in biology", which fully summarizes its position in the ecosystem.
5. Plant cultivation and rational use of light energy are the contents of the textbook, which aims to make students understand the concepts of science, technology and society (STS), and this part is easy to arouse students' enthusiasm for discussion.
Teaching suggestion
1, Introduction
Because the related issues involve a wide range, especially some topics that people are widely concerned about, there are many topics that can be introduced in this section, such as some ecological crises facing the world, such as grain, fossil energy and environmental pollution. Or cultivation methods of flowers, crops, fruits and vegetables or measures to increase yield; Or from some natural disasters, locusts, sandstorms and so on; Or the difference of assimilation between animals and plants. This way of introduction can consciously cultivate students' sense of social responsibility, and also better reflect the spirit of science and technology and social education.
2. the discovery of 2.XX
Special attention should be paid to this part of teaching, which is not only the education of the history of science, but also the difficulty of scientific discovery that students can realize from the research course of scientists for more than 200 years. At the same time, we can feel the importance of scientific research methods; The experimental design is ingenious. For example, in 1880, German scientist engelmann proved that chloroplasts are places where oxygen is released from chloroplasts. And the important role of the discovery and comprehensive application of new technologies and theories in scientific discovery, and experience the concepts of science, technology and society again. For example, without the progress of nuclear science, there would be no radioisotope technology, and there would be no experiment in which American scientists Rubin and Carmen used isotope labeling to prove that all the released oxygen came from water.
3. When guiding students to discuss the photosynthetic pigments in chloroplasts and their physiological functions, Experiment 8, the extraction and separation of pigments in chloroplasts, can be used as a verification experiment after the teaching of photosynthetic pigments, and can also be used as an exploratory experiment of photosynthetic pigments. This will not only enable students to learn relevant methods, stimulate their interest in learning biology, but also deepen their understanding of this part of knowledge and cultivate their experimental inquiry ability. When guiding students to discuss the absorption spectrum of pigment in chloroplast, the absorption spectrum curve of photosynthetic pigment in the textbook can be used as the material of the textbook to train students' ability to analyze the curve.
4. Process teaching is the core content of this part. When teaching, we can start with the total reaction, or compare it with the total reaction in junior high school. Teachers can teach, students can discuss, and students can put forward the hypothesis of oxygen source according to the total reaction, that is, whether the oxygen in water comes from water or carbon dioxide, or both. Classes with good conditions can also let students find ways to prove these assumptions to train their experimental design ability. Through the analysis of the total reaction formula, students can clearly understand the key issue of the source of oxygen.
On the basis of students' understanding of the total reaction formula, students can make clear another important point, that is, the multi-step reaction is very complicated, and the total reaction formula can not express the specific process, thus naturally introducing the study of light reaction and dark reaction process.
In the teaching of light reaction and dark reaction, because they are relatively boring chemical reaction processes, students can't see these changes in the experiment, so they can show them to students in the form of charts, tables or multimedia animations, so that students are willing to accept them. Students can "see" the microscopic chemical changes of substances with their own eyes, which also reduces the difficulty of understanding this part of knowledge. It is also necessary to guide students to discuss the difference and connection between bright reaction and dark reaction, especially to pay attention to the connection between them.
If time permits, students can also be guided to discuss the influencing factors, and then discuss "how to improve photosynthetic efficiency" and "what measures should be taken to improve agricultural output?" And other issues, so that students realize the practical value of learning biological theory, and strengthen students' concept of applying what they have learned and linking theory.
5. The significance of teaching means that students can collect information about food, fossil energy, environmental pollution and biodiversity destruction before class. In class, several typical cases are selected to arouse students' thinking and discussion around the ecological significance of this center, so that students can truly realize that "it is the most basic energy and material metabolism in biology."
6. The teaching of plant cultivation and rational utilization of light energy can be in the form of comprehensive discussion questions, such as: Can students put forward specific measures to improve crop yield in agricultural production by using principles? This kind of questioning ability allows students to have more imagination and thinking space, and it is also easy to discuss among high school students.
4. Excellent example of biology teaching plan in senior three.
Knowledge goal:
1, understand the concept and significance of sensory organs, as well as the structure and function of ears.
2, understand myopia and hyperopia, eye health knowledge, as well as the structure and function of the ear, hearing formation, ear health care.
Ability goal: to cultivate the ability to prevent myopia trachoma otitis media.
Emotional goal: cultivate good hygiene habits.
Important and difficult
Focus: the formation of eye structure and vision, ear structure and hearing.
Difficulties: the formation and abnormality of vision, the formation of hearing, and the structure of ears.
training/teaching aid
Eye-ear structure wall chart and visual and auditory formation schematic diagram, convex lens imaging experiment demonstration device, etc.
Class arrangement
This section is divided into 2 class hours.
teaching process
(first class)
(Sensory organs → eye structure → experimental demonstration of convex lens imaging → vision formation → myopia and hyperopia)
Introduce a new lesson: from the section "Any reflex begins with a receptor's feeling of stimulus", the topic is: sensory organs and human vision and hearing.
Main contents: Firstly, the organs composed of special receptors and their accessory structures are called sensory organs, and then it is pointed out that eyes and ears are sensory organs related to the formation of vision and hearing. It is further pointed out that vision is the most important function for us to understand the things around us. We must first learn the knowledge of eyes and vision.
It is pointed out that the structure of eyes is the basis of function. What is its structure? Let the students look at the pictures and observe the external structure of each other, and know the structural parts of the visible parts such as cornea, iris, pupil and sclera. Then show the schematic diagram, and briefly introduce the anatomical structure of eyeball from front to back and from outside to inside with the model. Summarize one by one in the form of blackboard writing, and finally briefly introduce the attached structure and function of eyeball.
Then it is pointed out that the first step of vision formation is that light enters the eyeball first, which is similar to an experimental phenomenon-demonstration lens imaging experiment, and students carefully observe the experimental process. On the one hand, the teacher introduced the experimental device simply and clearly, on the other hand, he reminded the students to pay attention to the relationship between the distance between the paper screen, convex mirror and candle and the imaging situation, and the relationship between the lens convexity and the imaging situation. Record the experimental results concisely.
Ask the students to observe the pictures and contact the experimental phenomenon just now. The teacher asked the students to answer: How is the image formed on the retina? Then it leads to the whole process of visual production step by step and summarizes it in the form of blackboard writing.
Then, when the distance and size of the object change, how to make the image on the retina clear? Teachers guide students to contact the eyeball structure, realize the significance of lens curvature adjustment, and at the same time lead to the phenomena of myopia and hyperopia and the methods of correction.
Summary: Briefly summarize the main points of this lesson.
5. Excellent example of biology teaching plan in senior three.
I. Knowledge
1, let students understand the concept of breathing.
2. Make students master the process of aerobic breathing.
3. Let students know the similarities and differences between aerobic respiration and anaerobic respiration.
4. Let students understand the meaning of breathing.
5. Let students understand the essence of breathing.
6. Let students understand the differences and connections between respiration and photosynthesis, the two most important physiological processes in biology.
Second, ability.
1. By analyzing the process of aerobic breathing, train students' ability to analyze problems and cultivate students' good thinking quality.
2. By comparing the similarities and differences between aerobic respiration and anaerobic respiration, and the similarities and differences between photosynthesis and respiration, cultivate students' list comparison ability and inductive ability.
Third, feelings, attitudes and values.
By guiding students to discuss the principles of photosynthesis and respiration, measures to improve crop yield can stimulate students' interest in learning biology, enhance their understanding of science, technology and society, cultivate students' awareness of caring about the science around them, and educate them on the values of life science.
Teaching suggestion
Textbook analysis
This section is one of the key contents of this chapter. The textbook includes four parts: aerobic respiration, anaerobic respiration and the meaning of respiration.
1, the concept of respiratory function
The concept of respiration mentioned in the textbook is basically similar to that mentioned in the junior high school biology textbook, but it is emphasized that it occurs in cells, and the oxidized substrate is not only glucose, but also sugars, lipids and protein, which plays a connecting role for students to further learn the principle of respiration.
2. Aerobic breathing
The textbook first points out that aerobic respiration is the main form of respiration of higher animals and plants, and respiration usually refers to aerobic respiration.
Then the textbook gives the general reaction formula of aerobic respiration, and on this basis, it expounds the three stages of the whole process of aerobic respiration with illustrations, and points out the place where each stage is carried out:
The first stage is the dehydrogenation of glucose to produce reducing hydrogen, propiolic acid and a small amount of ATP. This stage is carried out in the cytoplasm matrix.
The second stage is the continuous dehydrogenation of propionic acid, and at the same time, water molecules need to participate in the reaction to generate reducing hydrogen, carbon dioxide and a small amount of ATP, which is carried out in mitochondria.
The third stage is that the hydrogen released in the first two stages combines with oxygen to generate water and produce a large amount of ATP, which is also carried out in mitochondria.
3. Anaerobic breathing
The textbook first explains that organisms can generally breathe without oxygen, and respectively expounds the anaerobic respiration of higher plant cells and their places and the anaerobic respiration of higher animal cells and their places.
Then the textbook added that some parts of some higher plants can also produce lactic acid when they breathe anaerobically; At the same time, the textbook also briefly introduces the evolution of aerobic respiration in small print.
Teachers should supplement the concepts of anaerobic respiration and fermentation, which are easily confused by students.
4. Similarities and differences between aerobic respiration and anaerobic respiration
The textbook compares the difference between aerobic respiration and anaerobic respiration in the form of charts and diagrams.
5. The meaning of breathing.
The textbook discusses the significance of breathing from two aspects: one is to provide energy for the life activities of organisms; Secondly, it provides energy for the synthesis of other compounds; Here, teachers need to make appropriate supplements to the meaning of breathing, such as: the intermediate metabolites in the process of breathing are the raw materials for the transformation of various substances; Another example is the emergence of aerobic respiration, which greatly promotes the speed of biological evolution.
Teaching suggestion
1, Introduction
Because breathing is also one of the important biological principles in junior high school biology class, students still have evidence about the basic material changes and energy changes of breathing. Therefore, the introduction can be based on students' existing understanding of respiratory function, and teachers can design question series to test students' understanding of respiratory function, and combine the introduction with the concept of respiratory function in teaching materials for teaching.
2. Aerobic breathing
(1) Let students compare the total reaction equation of aerobic respiration given in biology textbooks for junior and senior high schools, and realize the fact that both products and reactants of aerobic respiration need water in comparison.
(2) The process of aerobic respiration
① Material changes and ATP production during aerobic respiration.
When guiding students to discuss the three stages of aerobic respiration with glucose as the substrate, the following teaching methods can be adopted: teachers write chemical reaction procedures, and at the same time let students balance the reaction formulas, and at the same time refer to textbooks and charts for teaching.
A, the first stage: in the matrix of cytoplasm, one molecule of glucose is decomposed into two molecules of propionic acid, and four molecules are removed at the same time; In the process of glucose decomposition, a small amount of energy is released, part of which is used to synthesize ATP and produce a small amount of ATP.
B, the second stage: pyruvate enters the matrix of mitochondria, and the hydrogen in two molecules and six water molecules of pyruvate is completely removed, and 20 molecules of pyruvate are removed, so that pyruvate is oxidized and decomposed into carbon dioxide; In this process, a small amount of energy is released, and part of it is used to synthesize ATP, resulting in a small amount of ATP.
C, the third stage: on the inner membrane of mitochondria, 24 * * * shed in the first two stages combines with 6 O2 absorbed from the outside or produced by chloroplast photosynthesis to form water; In this process, a lot of energy is released, and part of it is used to synthesize ATP, producing a lot of ATP.
Teachers can guide students to analyze the three stages of aerobic respiration.
(3) Energy changes during aerobic respiration
The teacher should explain to the students that glucose is completely oxidized and decomposed during aerobic breathing. After 1mol of glucose is completely oxidized and decomposed, * * * releases 2870kJ of energy, of which 1 16 1kJ of energy is stored in ATP, and the rest energy is dissipated in the form of heat energy.
(4) After students fully understand the three steps of aerobic breathing, teachers should ask some comprehensive questions to help students deepen their understanding of aerobic breathing in the discussion.
In order to make students set up the concept of applying what they have learned, and to review what they learned in the last class, teachers can also ask some questions about applying the principle of aerobic breathing in production practice for students to discuss and deepen their understanding of aerobic breathing. For example, teachers can design questions like:
"If someone asks you how to store crop seeds, vegetables or fruits for a long time, can you use the principle of respiration you have learned to provide some valuable suggestions or measures?"
3. Anaerobic breathing
(1) The concept of anaerobic respiration
Teachers can guide students to discuss: "Under what circumstances can organisms lack oxygen?" This naturally leads to the next question: "How do organisms breathe under anoxic conditions?" Thereby introducing the learning of anaerobic respiration.
The teacher should explain to the students that what we usually call breathing actually refers to aerobic breathing, which is carried out under aerobic conditions. Anaerobic respiration generally refers to the process that cells decompose glucose and other organic substances into incomplete oxidation products under anaerobic conditions, and release a small amount of energy through the catalytic action of enzymes. This process is called anaerobic respiration for higher organisms, and it is customarily called fermentation for microorganisms (such as lactic acid bacteria and yeast).
(2) The process of anaerobic respiration
Teachers can teach by writing chemical equations and letting students balance their reactions, so as to guide students to analyze and discuss the anaerobic respiration process and place of higher plant cells and higher animal cells. Finally, the whole process of anaerobic respiration is summarized.
The first stage: in the matrix of cytoplasm, it is exactly the same as the first stage of aerobic respiration.
In the second stage, propiolic acid is decomposed into alcohol, carbon dioxide or lactic acid under the catalysis of different enzymes in the cytoplasm matrix.
In order to deepen students' understanding of anaerobic respiration, teachers can design some questions for students to discuss.
4. Comparison between aerobic respiration and anaerobic respiration
From glucose to propiolic acid, aerobic respiration and anaerobic respiration are exactly the same, but the way to form products from propiolic acid is different.
Teachers can guide students to compare the similarities and differences between aerobic respiration and anaerobic respiration in the form of tabular solution.
Teachers provide students with valuable discussion topics closely related to students' lives to strengthen their understanding of the relationship. If you can ask questions:
Do you do a lot of exercise every day? Have you ever thought that when you do different forms of exercise, your body actually provides you with energy in different ways?
② Does the virus breathe aerobically or anaerobically?
5. Similarities and differences between aerobic respiration and photosynthesis.
Teachers can guide students to compare the similarities and differences between aerobic respiration and photosynthesis in the form of tabular solution.
At this time, teachers can provide students with some topics related to human production practice for analysis, thus training students' ability to analyze problems. If the teacher can ask:
"Can we use the principles of photosynthesis and respiration to put forward specific measures to increase crop yield in agricultural production?"
6. The meaning of breathing.
Teachers can guide students to analyze the meaning of breathing from the following aspects.
(1) provides energy for the life activities of organisms;
(2) providing energy for the synthesis of other compounds;
(3) The intermediate metabolites during respiration are the raw materials for the transformation of various substances. For example, propionic acid, an intermediate product of respiration, can be quickly converted into glycerol, amino acids, enzymes, pigments, plant hormones and other substances under the action of enzymes. It can be said that respiration is the hinge of the mutual transformation of various organic substances in the organism, which connects the glucose metabolism, lipid metabolism and protein metabolism in the organism into a whole.
(4) The appearance of aerobic respiration greatly promoted the speed of biological evolution.