Teaching objectives of the teaching plan of chemistry "important nutrients for human beings" in the second volume of ninth grade published by People's Education Press.
Knowledge and skills
1. Understand nutrients such as sugar, oil, vitamins, inorganic salts and water.
2. Understand the relationship between sugar, oil, vitamins and human health.
3. Through calculation, we know that protein, sugar and oil provide energy for human body through oxidation.
Process and method
1. Learn the method of autonomous learning by reading textbooks and discussing.
2. By understanding, analyzing and comparing a large number of pictures in teaching materials, learn to understand chemical knowledge from reading pictures.
Emotions, attitudes and values
By studying the significance of nutrients to human life activities, we realize the importance of a reasonable diet.
Emphasis and difficulty in teaching
focus
Know common nutrients such as sugar, fat and vitamins.
difficulty
To understand the relationship between common nutrients such as sugar, fat and vitamins and human health.
teaching tool
Multimedia courseware.
teaching process
First, the introduction of new courses.
When people are hungry, they feel weak. At this time, their first thought is to eat. Marathon runners should drink glucose water halfway; Patients with poor digestion and absorption ability should be injected with glucose water intravenously.
People need heat and energy to maintain a certain body temperature and engage in various activities. Why eating or ingesting glucose can provide people with the calories and energy needed for activities?
This requires us to know something about sugar.
[blackboard writing] 1. sugar
Second, the new curriculum teaching
[Explanation] Generally speaking, organic compounds such as glucose, starch and cellulose are sugars, also known as carbohydrates. Sugar is the product of photosynthesis of green plants and an important source of energy needed by animals and plants. 60% ~ 70% of the total energy of human food supply comes from sugar.
Sugar is the main source of energy needed by animals and plants.
When people eat, the sugar substance that they ingest from staple foods such as rice, flour, corn and potatoes is starch.
[Blackboard] 1. Starch [(C6H 10O5)n]
The relative molecular weight of starch ranges from tens of thousands to hundreds of thousands. Food starch reacts with water through enzymes in the human body and finally becomes glucose. The chemical formula of glucose is C6H 12O6.
[Blackboard] 2. Glucose (C6H 12O6)
Glucose is a sweet white solid. Glucose is absorbed into the blood through the intestinal wall to become blood sugar, which is transported to various tissues and organs of the human body to provide nutrition for human tissues, and is converted into starch under the action of enzymes and stored in the liver and muscles.
In human tissues, glucose is slowly oxidized into carbon dioxide and water under the action of enzymes, and at the same time, energy is released for physical activities and the need to keep body temperature constant.
[blackboard writing] C6H 12O6+6O26CO2+6H2O
In the above reaction, about 15.6 kJ of energy is released per gram of glucose.
Transition: The cane we usually eat contains sucrose.
[Blackboard] 3. Sucrose (C 12H22O 1 1)
Sugar content in beet is also extremely high. The main component of white sugar, rock sugar and brown sugar eaten in daily life is sucrose, which is a commonly used sweetener in food.
Transition: maltose is also a common carbohydrate. Maltose is the main component of caramel, such as sorghum molasses.
[blackboard writing] 4. Maltose (C 12H22O 1 1)
[Question] Why does it feel sweet to chew rice steamed bread in your mouth?
[Explanation] When you chew rice and steamed bread in your mouth, you will feel sweet. This is because saliva contains amylase, which can catalyze the hydrolysis of some starch in food into maltose. The remaining starch is hydrolyzed into maltose by pancreatic amylase in the small intestine. Maltose is hydrolyzed into glucose which can be absorbed by human body under the catalysis of maltase in intestinal juice.
Normal people should consume a certain amount of starch and other compounds every day, and maintain a certain concentration of glucose in the blood. If the intake of these compounds is not enough, it will lead to low blood sugar content (medically called? Hypoglycemia). People with hypoglycemia will have symptoms such as fatigue, fatigue, coma and shock. Because glucose can be directly absorbed by human body without digestive process, patients with weakness and hypoglycemia can quickly supplement nutrition by intravenous injection of glucose solution.
[Transition] Oil, another nutrient in food, is also an important energy-supplying substance in animals. What do we need to know about oil and fat?
[blackboard writing] 2. bribe
Please read the relevant contents of the textbook and summarize.
[Teacher's summary, blackboard writing] Grease is a general term for grease; Grease is an important energy-supplying substance, and each gram of grease releases 39.3 kJ of energy when it is completely oxidized in human body, which is twice as much as sugar. Fat in the human body is a backup energy source to maintain life activities.
[Projection Classroom Exercise] The sugar content of peanuts is about 24% (mass fraction). Oil is about 39%, protein is about 26%; The sugar content of wheat is about 76%, the oil content is about 2%, and protein is about 1 1%. What is the energy released by the complete oxidation of 50 g peanuts and 50g wheat in the body?
[Answer] According to the textbook information:
The complete oxidation of 1 g oil can release 39.3 kJ of energy.
1 g complete oxidation of glucose can release 15.6 kJ energy.
The complete oxidation of 1 g protein can release about 18 kJ of energy.
In 50 grams of peanuts, oil content: 50 grams? 39% =19.5g.
Sugar: 50 g? 24% =12g
Including protein: 50 g? 26% =13g
In 50 grams of wheat, oil content: 50 grams? 2%= 1 g
Sugar: 50 g? 76% = 38g
Including protein: 50 g? 11%= 5.5g.
The energy released by complete oxidation of 50 grams of peanuts in the body is as follows:
19.5? 39.3+ 12? 15.6+ 13? 18 =1187.55 (kJ)
The energy released by complete oxidation of 50 grams of wheat in the body is:
1? 39.3+38? 15.6+5.5? 18=73 1. 1 (kJ)
[Transition] At the beginning of the 20th century, people thought that adequate intake of protein, sugar, fat, minerals and water could meet the health needs. At that time, some adults and children had obstacles in their growth and development due to insufficient vitamin intake; Some people are also malnourished because of insufficient vitamin intake. These diseases have become a medical problem. In the middle and late 20th century, people discovered various vitamins and their functions. Understanding the important role of vitamins is the greatest progress in nutrition in the 20th century.
[blackboard writing] 3. vitamin
There are more than 20 kinds of vitamins, which are substances with complex molecular composition and structure. Most of them can't be synthesized in human body and need to be ingested from food. Vitamins are rarely needed in human body, but they can play a role in regulating metabolism, preventing diseases and maintaining health. Lack of a certain vitamin will make people sick, such as lack of vitamin A, it will cause night blindness; Lack of vitamin c can lead to scurvy. Fruits, vegetables, seed foods, animal livers, chicken, fish, cod liver oil, eggs, milk and goat's milk are all rich in vitamins.
[Blackboard Book] Although the amount of vitamins needed by the human body is small, it is very important.
As long as the diet contains various vitamins, there will be no partial eclipse, and vitamins will generally not be lacking. If the method of cooking food for a long time is wrong, so that the vitamins in food are destroyed or lost, people are prone to some diseases. Therefore, if the vitamin intake is insufficient, we should pay attention to supplement it. Now people can synthesize or extract some vitamins from some foods by artificial methods to make vitamin preparations.
[Projection data] Characteristics of several vitamins
Vitamin A is slightly soluble in water and vitamin D is insoluble in water, both of which are soluble in oil. Preparations of vitamins A and D are oily. Vitamin B is soluble in water, easy to be lost when boiled, easy to be destroyed when heated at high temperature, and difficult to be stored in the body. It should be taken regularly to ensure the needs of the human body. Vitamin C is soluble in water and easily destroyed by oxidation (especially in heating or alkaline environment). When cooking, it is best not to soak in water. It is best not to mash or cut thin before cooking. It's best to cook with boiling water, and don't keep it warm for too long before eating. Eating cold vegetables (such as vegetable salad) or lettuce can get more vitamin C, and vitamin C preparations can't be stored for long.
Teaching objectives of teaching design of important nutrients for human body
Teaching objectives
1. Knowledge and skills
(1) Understand that nutrients refer to protein, sugar, oil, vitamins, inorganic salts and water.
(2) Understand the relationship between protein, sugar, oil, vitamins and human health.
2. Process and method
(1) Learn about information related to intake by reading materials and accessing relevant materials on the Internet.
(2) From what I have learned, I have realized the importance of various nutrients to people's life activities and the importance of reasonable dietary arrangements.
3. Emotional attitudes and values
(1) realized that chemistry is closely related to life, and on this basis, he became interested in learning chemistry.
(2) Make students love life more and develop good living habits, thus promoting their healthy growth.
Emphasis and difficulty in teaching
Teaching focus
1. The main function of protein in human body.
2. Broaden students' horizons.
Teaching difficulties
1. Understand the role and nutritional value of nutrients in human life activities.
2. Understand the importance of a reasonable diet.
teaching tool
Prepare multimedia courseware as teaching AIDS, etc.
teaching process
Introduce a new course
Students, please recall what you had in the morning. Students discuss and communicate.
raise a question
We know that human beings must eat food to maintain life. So, what are the nutrients in the food needed for human survival? What are the functions of these nutrients?
Courseware display
Textbooks P90+02- 1, P93+02-6 and P94+02-7.
Inductive summary
The survival and health of human life cannot be separated from six substances, such as protein, sugar, oil, vitamins, inorganic salts and water, which are usually called human nutrients.
raise a question
What is the significance of these nutrients to human life activities?
Guide reading
Divided into four groups, they were assigned to introduce the contents of protein, sugar, oil and vitamins in the reading materials, and combined with the relevant materials arranged by the teacher before class, they cooperated in the group and discussed the following tasks within a limited time: Write a self-introduction essay in the first person with a self-made topic. Requirements: briefly introduce the basic situation of a certain kind of nutrients, focusing on its important role in human health.
Summary (the above table can be displayed by courseware)
raise a question
We know the important role of several nutrients in human body, so how can we take these nutrients in a balanced way in real life?
Exchange answers
Diversified food intake, no partial eclipse, no picky eaters, and develop good eating habits.
Classroom consolidation exercises
Please think about and answer the following three classroom exercises:
1. Grandma Xiaoming made the following recipes for him to welcome the senior high school entrance examination: rice, roast chicken, egg soup, sweet and sour fish and spicy tofu. In order to make the nutrition balanced, you think it's best to add ()
A. beef, shrimp and vegetable ice cream
Analysis of human body needs sugar, protein, oil, vitamins, inorganic salts and water. According to the recipe, rice mainly contains starch (sugar), while roast chicken, egg soup, sweet and sour fish and spicy tofu mainly contain protein, oil, inorganic salt and water; As we all know, the nutrient lacking in diet is vitamins.
Answer c
2. The following statement is incorrect ()
A. protein must contain nitrogen and oxygen.
B.this enzyme is a catalytic protein.
C. this enzyme will reduce its activity at high temperature.
D amino acids can be absorbed by human body, but cannot be synthesized into protein.
Protein can be gradually hydrolyzed into amino acids under the action of digestive juice, and amino acids can be absorbed by the human body and recombined into various protein needed by the human body, so item D is wrong.
Answer d
The following table is the instructions on the food packaging bag. Choose a substance from the ingredients in the table below and fill it in the corresponding horizontal line.
(1) is rich in protein, (2) is rich in sugar,
(3) rich in oil and (4) rich in vitamins.
Generally, protein-rich foods include eggs, milk, meat and beans. Foods rich in sugar include rice, flour and potatoes. Oily foods include all kinds of animal and vegetable oils; Foods rich in vitamins include vegetables and fruits.
Answer (1) fresh eggs (or milk powder) (2) white sugar (or refined flour) (3) refined vegetable oil (or cream) (4) lemon juice.
Reading discussion
Please read the textbooks P92 and P94. Information? , discuss and answer the following questions:
1. Some people use formaldehyde solution to soak aquatic products for sale. What are the disadvantages?
2. Why is smoking harmful to health?
3. Why should moldy food never be eaten?
4. Why do some students feel very tired in the long and short games of the sports meeting? Why do some students eat some glucose before the game? If you eat some peanuts or wheat instead, will it be effective?
Summary after class
Course summary
In this lesson, we learned the characteristics of nutrients such as sugar, protein, oil and vitamins and their effects on human body. I believe the students have gained something.