1. high school biology courseware
First, the teaching objectives
Knowledge:
1, indicating cell differentiation.
2. Give examples to illustrate the totipotency of cells.
Ability: Collect and analyze data about stem cell research progress and human health.
Second, teaching priorities, difficulties and solutions
1, teaching focus:
⑴ The concept and significance of cell differentiation.
⑵ The concept of cell totipotency. Solution: contact the knowledge about tissues, organs and systems learned in junior high school; Describe the characteristics of cell morphology, structure and function in different tissues. Let students understand the concept and significance of cell differentiation from the establishment of various tissues, organs and systems during individual development.
2. Teaching difficulties: the concept and examples of cell totipotency.
Solution: From the point of view that somatic cells are generally propagated by mitosis from fertilized eggs, and the differentiated cells all have the same set of chromosomes as fertilized eggs and carry DNA molecules with the characteristics of this species, the totipotency of cells is obtained.
Iii. Schedule: 1 class hour
Fourth, teaching method: explanation method. Five, prepare teaching AIDS: courseware
Students' activities of intransitive verbs
1, inspire students to get the concept of cell totipotency through concrete examples.
2. Guide students to read textbooks and find out the relevant knowledge points of cell differentiation.
Seven. teaching program
[Discussion] 1. Why doesn't the number of blood cells in healthy people decrease with the death of blood cells? 2. What is the relationship between bone marrow and the formation of blood cells?
I. Cell differentiation and its significance
Show the picture of the textbook P 1 17, 1 18 to explain.
1, the concept of cell differentiation: abbreviated.
2. Guide students to discuss the following questions:
(1) An example of cell differentiation that is ubiquitous in biology. For example, in the process of plant radicle developing into roots, the cells in meristem area are constantly dividing, and almost all the cells formed are cubes. With the growth of cells, they become rectangular cells in the elongation zone, and then differentiate into cells with different shapes, structures and functions, such as vessel molecules, root hair cells and parenchyma cells, which are the transport tissues in the mature zone. Another example is that the embryonic cells of animals form multicellular organisms. Stem cells regenerate various cells and so on. ⑵ The process of cell differentiation. The future of cell differentiation depends on the realization of genetic information before the cell appearance changes significantly. The changes in the morphology, structure and physiological function of differentiated cells are first due to the changes in chemical substances in cells, such as structural proteins and enzymes that catalyze chemical reactions, and then gradually change irreversibly. Therefore, differentiation is persistent,
A steady and gradual process. (3) The significance of cell differentiation. Generally, the starting point of multicellular biological development is a cell (fertilized egg). Cell division can only produce many identical cells, and only through cell differentiation can embryos, larvae and adults be formed. Cell differentiation is the basis of individual development.
3. Characteristics of cell differentiation: persistence and irreversibility.
4. Time of cell differentiation: In the whole life process, the embryonic stage reaches the limit.
5. The essence of cell differentiation: the result of gene selective expression.
6. Will the genetic material change during cell differentiation?
Second, the totipotency of cells.
1, the concept of cell totipotency The teacher showed the pictures of carrot tissue culture in the textbook P 1 19, and introduced the experiment of American scientist Steward. Because somatic cells generally proliferate through mitosis, generally differentiated cells have the same set of chromosomes as fertilized eggs and carry the same DNA molecules of this species. Therefore, differentiated cells have the potential to develop into complete individuals. Under suitable conditions, some differentiated cells have the ability to resume division and re-differentiate into complete new individuals. Totipotency of cells means that differentiated cells still have the potential to develop into complete individuals.
Highly differentiated plant cells are still totipotent. (Introduce the application of plant cell totipotency) Highly differentiated animal cells have limited totipotency as a whole. But the nucleus is still omnipotent. For example, sheep mammary gland nucleus was transplanted into enucleated egg cells, and cloned sheep Dolly was bred.
2. Stem cells in animals and humans still have the ability to divide and differentiate, which is called stem cells. For example, there are many hematopoietic stem cells in human bone marrow. There are many kinds of stem cells, which can be divided into adult stem cells and embryonic stem cells. It can also be divided into three types: stem cells that can differentiate into various types of cells needed for life activities are called totipotent stem cells, which can form a life itself; Stem cells that cannot independently develop into complete individuals but can differentiate into various types of cells are called pluripotent stem cells; Cells that can differentiate into specific organs and specific physiological functions are called pluripotent stem cells.
[Data Collection and Analysis] Stem cell research progress and human health, discuss and answer questions related to the textbook P 120.
Third, summary.
The concept of cell differentiation, the biological significance of cell differentiation and the totipotency of cells.
Fourth, homework
P 120 exercise
Five, the blackboard design
Cell differentiation in the second quarter
1. cell differentiation and its significance
1, concept:
2, characteristics: lasting, irreversible
3. Time: In the whole life process, the embryonic period reaches its limit.
4. Importance:
5. Essence: Gene selective expression
2. High school biology courseware
Teaching objectives
Knowledge and ability:
1. This shows that antibiotics play an important role in controlling infectious diseases.
2. Briefly describe the action mechanism of commonly used antibiotics.
3. List examples of unreasonable use of antibiotics in life, and discuss and analyze the harm of abusing antibiotics.
4. Agree to the rational use of antibiotics.
Process and method:
This lesson mainly adopts the way of students' group cooperation and inquiry. By browsing the website materials, we can understand some practices of people abusing antibiotics in their lives, have a heated discussion, understand the history and mechanism of antibiotics, and understand the relationship between science, technology and society in group cooperation and inquiry. Cultivate students' spirit of cooperative inquiry and their ability to learn independently, collect and process information.
Emotional attitudes and values:
Cultivate students' concern for society and people's health and cultivate their sense of social responsibility.
Teaching focus
1. Examples of antibiotic abuse in life and its harm.
2. Rational use of antibiotics.
Teaching difficulties
Examples of abuse of antibiotics and its harm.
teaching method
The combination of teaching methods and students' cooperative learning
Teaching time
1 class hour.
teaching process
Teacher: Teachers and students discuss the examples and harms of abusing antibiotics in daily life.
Student: Discuss and exchange people's understanding of the use of antibiotics in daily life in groups. Each student put forward his own practice of using antibiotics.
Teacher: Use courseware to show some practices of abusing antibiotics in life.
(Student activities) Students discuss in groups.
Teacher: Show some TV advertisements about antibiotics and discuss with students.
Courseware display: After a classmate has a cold, he should have an intravenous drip. I used penicillin for the first time, but I still used penicillin for the second time, but the dosage was more than the first time. He thinks the more the better, the faster. Take this example, the students have a heated discussion.
After studying in groups, students communicate. Answer the following questions and show them:
1. History of antibiotics
The molecular formula of (1) penicillin
By reading the textbook, students can master the specific writing of penicillin molecules.
(2) Mechanism of action of antibiotics: (Students read the textbook and discuss)
A. Structure of bacteria
B. Mechanism of action
Antibiotics mainly affect the structure and physiological function of pathogenic microorganisms such as bacteria by interfering with their metabolic processes, so as to achieve the purpose of inhibition and killing.
2. Rational use of antibiotics
(1) Students discuss the schematic diagram of bacterial resistance and put forward their own understanding and views.
(2) Analyze the materials in the textbook and list examples of irrational use of antibiotics.
3. How to protect health and use less medicine? Or no drugs.
4. How to use antibiotics in daily life? Through the discussion in this class, students talk about their own experiences.
Classroom practice
1. In daily life, the following practices are correct for the use of antibiotics:
A. use penicillin as long as it is infected.
B. increase the dose and get better soon.
C. rational use of antibiotics according to the condition.
D. the effect of using antibiotics in time is better than using other non-antibiotics
2. The use of fermentation engineering can greatly increase the output of antibiotics, and the relevant statement is correct:
A. In fermentation engineering, anaerobic respiration of organisms is used.
The antibiotic is protein.
C. antibiotics can deal with all pathogens.
D. Different antibiotics play different roles.
3. The mechanism of action of antibiotics is
A. decompose protein to provide nutrition for cell reproduction.
B it interferes with the metabolic process of pathogenic microbial elements such as bacteria, thus affecting its structure and physiological function.
C. is to ensure the activity of cells.
D. provide nutrients for cell metabolism.
Assign homework and do exercises according to the study plan.
Teaching reflection
Antibiotics are commonly used in our daily life, and rational use of antibiotics can achieve good results in treating diseases and saving lives. However, in daily life, different people do things differently. Some people advocate multi-use In the process of teaching, we can see that different people have different views. Through a class discussion and exploration, students have a reasonable understanding of the use of antibiotics.
3. High school biology courseware
First, the teaching objectives:
Knowledge and skills: briefly describe the main elements that make up cells. Said that the basic element of cells is carbon.
Understand how to detect compounds in biological tissues and explore the types of main compounds in cells.
Process and Methods: By detecting sugar, fat and protein in biological tissues, the types of main compounds in cells were discussed.
Emotion and attitude: identify with the materiality of life.
Second, the difficulties in teaching:
Understanding the main elements that make up cells is the focus of this lesson, but it is difficult to detect several substances in biological tissues by experimental methods.
Third, teaching strategies:
1. Use "problem discussion" to create problem situations, so that students can learn new knowledge through observation, discussion and communication.
The main purpose of this section is to let students understand the material composition of cells and identify with the materiality of life. Because students have already learned the basic knowledge of chemistry in the third grade, when they enter this part of the study, they can compare the contents of some elements that make up the crust and cells, put forward their own questions, and realize that there are similarities and differences between the elements that make up the organism and the elements that make up the crust in the communication with other students. In response to the questions raised by students, teachers should guide students to observe the main elements (cell fresh weight percentage) and main elements (dry cell weight percentage) of human cells respectively, and then introduce the macro elements and trace elements that constitute cells.
2. Use chemical knowledge to solve the problem why carbon is the basic element of cells.
If students have a good understanding of atomic structure, it is suggested that teachers guide students to recall the distribution characteristics of electrons outside the nucleus of carbon atoms and the properties of carbon, so as to lay a foundation for students to understand that carbon chains are the skeleton of biological macromolecules.
Students are familiar with the periodic table of elements, and it is easy to find the position of carbon in 14 family. Its atomic number is 6, which means that a carbon atom has 6 protons in the nucleus and 6 electrons outside the nucleus. Because of the different electron configurations, there are four electrons in the outermost layer, so that carbon atoms have four valence electrons that can form bonds. It is these four valence electrons that can form more chemical bonds between carbon atoms and between carbon atoms and atoms of other elements. Since each carbon atom can form four chemical bonds, it is possible to form substances containing thousands or even more carbon atoms. Use students' existing chemical knowledge to understand the meaning of element C to life.
3. Use surface solution and "thinking discussion" to gain knowledge of compounds that make up cells and improve learning ability.
When learning the compounds that make up cells, it is not conducive for students to participate in learning activities if teachers directly explain the composition of cells. Therefore, teachers can use the questions in "thinking and discussion" to guide students to observe the superficial solutions in textbooks, acquire corresponding knowledge and information, and improve their learning ability.
Fourth, teaching tools: experimental materials, ppt slides
5. Preparation before class: Students preview the experimental process.
Sixth, the teaching process.
Teaching content, teacher activities and student activities
(1) Introduction
In the era of underdeveloped science, people are very mysterious about what life is made of, and think that life is made of special substances. Until the world of 19, people still thought that substances produced by organisms could not be synthesized in vitro. Students have studied chemistry for two years and know that all substances in nature are made up of elements. What are the elements that make up life?
Analyze the table of p 16 and ask questions. From this table, what impression can students have on the elements that make up life?
Analyze the data and express your own views (the elements that make up life also exist in the earth's crust, indicating the unity of biological and abiotic substances; In addition, the proportion of various elements in cells is different from that of the earth, which also shows the particularity of living matter.
(2) An overview of elements that make up cells and elements that make up life. Combine the two pie shapes of p 17 to guide students to observe and summarize. A large number of elements (C, H, O, N, P, S, K, Ca, Mg) can briefly introduce the functions of some elements; Trace elements. Ask a question: What elements do the two charts show? You can simply explain the position of carbon in life, observe the chart and summarize it.
(c) The compounds that make up cells guide students to complete the discussion.
Analyze the data and complete the discussion: 1 (omitted) 2 protein has the most organic matter and water has the most inorganic matter; 3. There are many sugars in potato tuber cells; Muscle cells contain more protein; There are more cells and fat in the subcutaneous tissue.
(4) Experiment: detect sugar, fat and protein in biological tissues. Problem-oriented: What did you choose for your experiment? Do you predict that there will be more organic matter in your experimental materials? What testing instruments and reagents do you choose?
Complete the experiment under the guidance of the teacher and report the experimental results.
(5) Practice
(6) Summarize the key points of the slide lesson: What are the main elements that make up cells (C, H, O, N)? Important compound (inorganic substances, organic substance) constituting cells; Methods for detecting substances such as sugar (including reagents, operations and reaction results)
4. High school biology courseware
The essence of knowledge
Sources, emissions and adjustments
Water balance and regulation
Drinking water, food substances and metabolism are regulated by hormones secreted by nerves and kidneys, skin and large intestine.
Balance and regulation of sodium salt
Mainly from salt, mainly through the kidney, followed by sweat, feces excretion aldosterone (mineralocorticoid) regulation.
Balance and regulation of potassium salt
Food is mainly regulated by the kidney, followed by unabsorbed aldehyde excreted with feces.
Significance: Water and sodium salt are of great significance for maintaining the osmotic pressure stability of extracellular fluid. Because people work at high temperature, they will lose most of the water and inorganic salts when they exercise vigorously or suffer from certain diseases (severe vomiting and severe diarrhea), which will affect the stability of blood pressure and heart rate.
Potassium plays an important role in maintaining osmotic pressure stability, myocardial relaxation and excitability of intracellular fluid's body.
Water plays an important role in decomposing waste.
Some problems about the regulation of water and salt;
1) Release and secretion of urinary hormones.
2) Aldehyde fixation has three functions: promoting sodium reabsorption, promoting potassium secretion and excretion, and promoting water reabsorption.
Understanding of examples
Example 1: A person suffers from acute gastroenteritis and severe diarrhea, with symptoms such as increased heart rate, decreased blood pressure and chills in limbs; To alleviate the above symptoms, you should:
A, input physiological saline. B, oral saline.
C, oral potassium salt water. D, input aldosterone.
Analysis: One of the symptoms in the problem is lack of water and sodium salt, and the other is that input is faster than oral administration.
A solid answer: A.
Example 2: Comparing the discharge characteristics of K and Na ions in human body, the differences are as follows:
A, eat more and row less B, eat less and row less C, don't eat less and row less D, row less.
Analysis: the characteristics of potassium ion discharge are: eat more and discharge more, eat less and discharge less, and discharge if you don't eat.
The discharge characteristics of sodium ions are: eating more and discharging more, eating less and discharging less, and not eating or discharging.
Answer: d
self-assessment
First, multiple-choice questions:
1, the main source of water in the human body and the main way to discharge it are: ()
First, it comes from drinking water and food and is excreted by the kidney.
B, from drinking water, food and skin.
C, substances from drinking water, metabolized and excreted by the lungs.
D, from drinking water, substance metabolism and large intestine excretion.
2. The life function of ionic inorganic salts (such as potassium and calcium ions in blood) does not include: ()
A, one of the cell structures.
B, maintain good normal physiological function
C, keep the cell morphology.
Adjust the PH value in cells.
3. The following statement about water regulation of human body is correct: ()
A, drink plenty of water, and the secretion of antidiuretic hormone increases.
B. When the thirst center is excited, the secretion of antidiuretic hormone decreases.
C, antidiuretic hormone secretion decreased, urine volume increased.
D, when the osmotic pressure in extracellular fluid decreases, the urine volume decreases.
4. The important hormones that regulate the balance of inorganic salts are: ()
A, antidiuretic hormone b, aldosterone tongC, epinephrine d, thyroxine.
5. The following only belong to the water release mode: ()
A, renal excretion b, large intestine excretion c, skin excretion d, lung excretion.
6. What can't promote the reabsorption of water by renal tubules is: ()
A, osmotic pressure increases. B, antidiuretic hormone increased.
C, plasma osmotic pressure increased. Aldehyde fixation increased.
Second, short answer questions:
7. The following figure shows the structural pattern of nephron. Answer the questions according to the pictures:
1) When people lack drinking water, lose too much water in the body or eat salty food, they can reduce urine excretion by promoting the secretion of neuroendocrine cells in hypothalamus () and (), and make the osmotic pressure of extracellular fluid return to normal.
2) When blood potassium increases or decreases, it can directly stimulate the secretion of () and (), thus promoting the reabsorption and secretion of () and maintaining the stability of the internal environment.
3) Through microscopic examination, it is found that there are many mitochondria in the cells that make up the renal tubule, which has physiological significance. The energy substances and oxygen needed by mitochondria are provided by (), and the carbon dioxide produced is taken away by () _ _ _ _ _.
Self-evaluation answer
First, multiple-choice questions:
1、A2、A； 3、C； 4、B； 5、D； 6. a.
Second, short answer questions
1, antidiuretic hormone 1 renal tubule 2 collection tube
2.tong 1 adrenal fixation renal tubular 2 sodium and potassium collection tube
3, providing energy, which is beneficial to the reabsorption of sodium and the secretion of potassium ions; 3. Renal tubular capillary blood; 3, renal tubular capillary blood.
5. High school biology courseware
First, the teaching purpose
Master the basic methods of identifying reducing sugar, fat and protein in biological tissues.
Second, teaching suggestions
This experiment is arranged as a verification experiment in the textbook, and schools with conditions can change it to an exploratory experiment, which is arranged before or at the same time as the lecture.
This experiment is not difficult, but it contains a lot of content and takes a long time. So we must make careful arrangements to finish it on time. The following points should be noted in the experiment.
1. Add teacher demonstration experiment. Before class, teachers should prepare experimental materials, utensils, instruments and reagents for demonstration experiments. At the same time, the identification experiments of reducing sugar, fat and protein were completed item by item. In the experimental class, the correct results of the three experiments are displayed on the platform and briefly introduced, so that students can compare their own experimental results with the teacher's demonstration experiments.
Students should cooperate with each other in the experiment. In the experiment of "Identification of Reducing Sugar", when one of the two students in each group prepares the biological tissue sample solution, the other student can boil the water with alcohol lamp to shorten the waiting time of the experiment. In the experiment of "fat identification", while one student is making temporary film, another student can debug the microscope. In addition, when completing the first two experiments, one student washes the test tube, wipes the glass slide and arranges the microscope, and the other student can operate the later experiments.
3. About the experiment of identifying reducing sugar, when heating the solution in the test tube, the upper part of the test tube should be clamped with a test tube clamp and heated in a big beaker filled with boiling water. Note that the bottom of the test tube should not touch the bottom of the beaker, and the mouth of the test tube should not face the experimenter, so as to avoid rushing out of the test tube when the solution in the test tube boils, causing burns. If the solution in the test tube is too boiling, you can lift the test tube clamp and let the bottom of the test tube leave the boiling water in the big beaker.
4. In the identification experiment of reducing sugar and protein, a part of sample solution can be set aside before identification, and compared with the color change of the identified sample solution, which can enhance the persuasiveness.
5. Lin Fei reagent solution A and solution B can be used only after they are mixed evenly. Do not add solution A and solution B to the tissue sample solution separately.
Third, reference materials.
Identification principle of reducing sugar There are many common reducing sugars in biological tissues, such as glucose, fructose and maltose. They all contain reducing groups (free aldehyde groups or free through groups) in their molecules, so they are called reducing sugars. There is no free hemiacetal hydroxyl group in sucrose molecule, so it is called non-reducing sugar and has no reducibility. In this experiment, the existence of reducing sugar in biological tissues can only be detected by using Lin Fei reagent, but non-reducing sugar can not be identified.
Linfei reagent is prepared from sodium hydroxide solution with mass concentration of 0. 1g/ml and copper sulfate solution with mass concentration of 0.05g/ml. After the two solutions are mixed, a light blue Cu(OH)2 precipitate is formed immediately. When Cu(OH)2 and glucose are heated, brick-red Cu2O precipitate can be formed, and glucose itself is oxidized to gluconic acid. The reaction formula is as follows:
CH2OH—(CHOH)4—CHO+2Cu(OH)2→CH2OH—(CHOH)4—COOH+Cu2O↓+2H2O
When the reducing sugar is identified by Fehling reagent, the color change process of the solution is light blue, brown brick red (precipitation).
Protein's identification principle When identifying whether protein is contained in biological tissues, biuret method is often used and biuret reagent is used. The biuret reagent consists of sodium hydroxide solution with a mass concentration of 0. 1g/ml and copper sulfate solution with a mass concentration of 0.0 1g/ml. In alkaline solution (NaOH), biuret (H2NOC-NH-ConH2) can react with Cu2+ to form purple or purplish red complex, which is called biuret test. Because protein contains many peptide bonds similar to biuret, protein can react with biuret reagent.
The experimental material for identifying reducing sugar is a common experimental material for preparing plant tissues, but it must be screened. In dicotyledonous plants, glucose, the main product of photosynthesis, is synthesized into starch and temporarily stored in leaves, so the leaves of dicotyledonous plants are not used as experimental materials. Some monocotyledonous plants, such as leek and iris, do not convert the initial products of photosynthesis into starch, so their leaves contain a lot of soluble monosaccharides. However, due to the deep color of chlorophyll in leaves, it plays a masking role in color reaction during identification, which leads to obvious experimental phenomena. Therefore, the leaves of monocotyledonous plants should not be used as experimental materials.
The most ideal experimental materials for this experiment are plant tissues (or organs) with high reducing sugar content, which are light or close to white in color, such as apples and pears. Comparatively speaking, the degree of color reaction is apple, pear, cabbage leaf and white radish in turn.
Preparation of experimental materials for identifying fat Select seeds rich in fat, such as peanut seeds (take cotyledons). Peanut seeds for experiment must be soaked for 3 ~ 4 hours in advance. The soaking time is short and it is not easy to cut into pieces; If the soaking time is too long and the tissue is too soft, the slice is not easy to form.
In the fat identification experiment, teachers can choose Sudan Red III or Sudan Red IV dye solution according to local conditions. The color reaction of Sudan ⅲ dye solution to fat is orange, and the color reaction of Sudan ⅳ dye solution to fat is red. Because Sudan IV dye solution has strong affinity with fat, the dyeing time is relatively short, generally around 1min. The experimental materials identified by protein are biological tissues (or organs) rich in protein, soybean seeds are commonly used as plant materials, and eggs (egg whites) are commonly used as animal materials. If soybean seeds are used, they must be soaked 1 ~ 2 days in advance, so it is easy to grind into pulp. Conditional schools can use ready-made soybean milk directly, buy it, or take it through small grinding institutions. Using soybean milk as experimental material can save experimental time.
If diluted egg white is used as experimental material, the effect will be better.
Preparation of linfei reagent
The mass concentration of solution A is 0. 1g/ml sodium hydroxide solution.
The mass concentration of solution B is 0.05g/ml copper sulfate solution.
When using, prepare temporarily. Drop 4 ~ 5 drops of solution B into 2mL of solution A, and use it immediately after preparation.
Sudan Red No.3 solution is to weigh 0. 1g Sudan Red No.3 dry powder, dissolve it in 100mL 95% alcohol, and use it after it is completely dissolved.
Preparation of Sudan IV solution Weigh 0. 1g Sudan IV dry powder, dissolve it in 50mL propylene ketone, then add 50mL 70% ethanol, and mix thoroughly before use.
Preparation of biuret reagent Take 10g sodium hydroxide and put it in a volumetric flask (or beaker with scale), add water to 100mL, fully dissolve it and pour it into reagent bottle to prepare a sodium hydroxide solution with a mass concentration of 0. 1g/ml. Put a rubber stopper on the bottle mouth, label it and write reagent A.
Take 1g copper sulfate, put it in a volumetric flask (or a graduated beaker), add water to 100mL, fully dissolve it, and pour it into reagent bottle to make a copper sulfate solution (blue) with a mass concentration of 0.0 1g/ml. Put a rubber stopper on the bottle mouth, label it and write reagent B.
1. Soil preparation: select a sandy loam plot with deep looseness, abundant sunshine and a large amount of organic matter as