-Photosynthesis of plants in the seventh grade biology courseware The following is the knowledge about photosynthesis of plants in biology. The following contents are for your reference.
1. What conclusion do you draw from Helmont's experiment?
2. How many steps can the experimental steps of "exploring the relationship between sunlight and organic matter" be divided into? What words can each step be simply summarized as?
3. In these steps, if you don't understand anything, mark it (group cooperation and mutual help).
experimental procedure
1. Leave potted geraniums in the dark day and night.
2. Cover a part of the leaf with black paper from the upper and lower sides, and then move it to the sun.
3. After a few hours, take off the leaves, remove the shading paper, put the leaves in a small beaker filled with alcohol, and heat them in water to make the chlorophyll contained in the leaves dissolve in the alcohol, and the leaves turn yellow and white.
5. Wash the leaves with clear water, then put the leaves in a Petri dish and drop iodine solution into the leaves.
6. Stop for a while, rinse off the iodine solution with clear water and observe what changes have taken place in the color of the leaves.
Secretion of knowledge points in the first book of junior one biology
-Secretion Volume I The first organism produces a substance from some cells, tissues or organs of the organism. For example, the stomach secretes gastric juice, flowers secrete nectar and bacteria secrete toxins.
The process by which cells obtain raw materials from blood or other extracellular fluids, synthesize certain substances in the cells and release them from the cells. Secretion patterns can be divided into two categories:
(1) Secretion is called exocrine when it is discharged into the body cavity or body surface communicating with the outside world through a catheter. For example, salivary glands discharge saliva into the mouth, gastric glands discharge gastric juice into the stomach cavity, and sweat glands discharge sweat to the skin surface.
(2) Cells only release their secretions into blood or extracellular fluid, which is called endocrinology, and endocrine glands secrete hormones into blood, which is called endocrinology. Some secretions released by cells play a physiological role in the body (such as digestive juice digesting food and hormones regulating the activities of some tissues and organs), while others are excreted as metabolites or redundant substances in the body (such as water, inorganic salts, urea, etc.). Sweat). Secretion is an energy-consuming process in which cells actively do work, and some fine structures in cells directly or indirectly participate in this activity.
Secretion is closely related to exocytosis, and secretion eventually leaves the cell in the form of spitting water. Cell phagocytosis means that when something outside the cell is attached to the cell membrane, this part of the membrane invades together with the attached substance and extracellular fluid, and the extracellular substance is swallowed into the cell, surrounded by vesicles, and finally forms free vesicles. The process of exocytosis is just the opposite. Under certain conditions (such as the arrival of nerve impulse and the influx of Ca2+), vesicles or particles filled with certain substances gradually move to the cell membrane, and then contact and fuse with it, and then the membrane at the contact point cracks, and the contents of vesicles are discharged from the cell.
Summary: According to the theory of "membrane recycling", the vesicle membrane can eventually flatten and become a part of the cell membrane, thus carrying out a new endocytosis process. Exocytosis and endocytosis may be two alternating processes.
Starch in the eighth grade biology examination questions
& ampMdash junior high school physics; In the eighth grade, starch can be regarded as a polymer of glucose. Starch can not only be eaten, but also be used to make dextrin, maltose, glucose, alcohol and so on. It can be extracted from starch-containing substances such as corn, sweet potato, wild acorn and pueraria lobata.
On the right are two test tubes A and B, which are filled with 2ml starch paste respectively, and then different substances are added respectively.
Oscillation makes it react fully. According to the picture, the answer is:
(1) The special chemical reagent for identifying starch is.
(2) It is the test tube that keeps the starch paste blue.
(3) The function of test tube B is.
(4) Exercise vigorously immediately after meals can inhibit digestion. Because during exercise, blood flows through the digestive organs (fill in "increase" or "decrease"), thus affecting digestion.
(5) Chemical digestion of starch starts from scratch.
Summary: The most abundant carbohydrate in human diet is starch. Starch is a polysaccharide based on glucose. Starch not only plays an active and important role in cooking and seasoning, but also has rich nutritional value.
The junior middle school biology innovation experiment teachers should be guided by the emergency teaching.
Innovative experimental teachers should be guided by teaching, constantly deepen the teaching concept and stimulate students' positive creativity.
Teachers should change teaching into guidance.
The purpose of middle school biology experiment is to let students know some basic scientific principles, understand the phenomena in nature, verify some simple natural laws, learn to use some basic instruments, master scientific research methods, and cultivate the habit and ability to explore and practice bravely. Therefore, teachers themselves should pay enough attention to experimental teaching, study hard, fully prepare, check and verify all kinds of equipment, and prepare all kinds of pharmaceutical reagents and materials needed for experiments to ensure the smooth progress of experimental teaching.
Thought determines behavior, and concept influences strategy. Teaching concept directly affects the choice of teaching methods, teaching means and teaching mode. In the traditional teaching method of biological experiment, teachers often demonstrate and explain at the same time, and the demonstration and explanation are very careful. They repeatedly emphasized the essentials of operation and strictly followed the operation steps of textbooks. This teaching method limits the space and room for students to develop their creative ability, which is not conducive to the cultivation of students' innovative ability. Teachers should make it clear that biological experiment teaching is not only a means to verify theoretical knowledge, but also to train students' experimental skills and skills with the help of specific experiments, so as to cultivate students' ability to find and solve problems, especially their ability to solve problems creatively. What teachers should do is to carefully organize biological experiment teaching activities and strengthen the guidance of students' experimental methods and instrument operation. In experimental teaching, the discovery teaching method is often adopted, and the teaching mode of "guiding students with questions before class, solving doubts in class, solving doubts by multiple teachers and communicating gains and losses after class" is adopted. Teachers' duty is not only to guide students to learn, but also to guide students to learn, that is, to teach students the methods of learning and change teaching into guidance. Because students are in the immature to mature development stage, teachers have the responsibility to promote students' development, especially their initiative, free exploration and innovative spirit, on the premise of respecting students' individuality. The primary task of teachers is to create a lively teaching atmosphere, so that students can form their psychological desire and personality characteristics of exploration and innovation. Creative education emphasizes the process of "discovering" knowledge, rather than simply obtaining results, and emphasizes creative problem-solving methods and the formation of inquiry spirit. In this teaching process, students are no longer passive listeners but active learners. Students' adaptability and creativity are also cultivated and developed in the process of solving problems.
Summary: The current teaching concept has been completely subverted. Class is student-oriented. Cultivate students' hands-on ability and increase classroom interaction.
The green leaves make starch under the light.
The green leaves of the first day make starch under light, and starch can be regarded as a polymer of glucose. Starch can not only be eaten, but also be used to make dextrin, maltose, glucose, alcohol and so on. It is also used to prepare printing paste, sizing fabric, sizing paper and pressed tablets.
Experimental problem: (except the last blank, 2, each blank is 1, with a total of 8 points)
1. When observing a specimen with a microscope, the correct one should be ().
A. Look at the eyepiece with your left eye and close your right eye. B. Look at the eyepiece with your right eye and close your left eye.
C. Look at the eyepiece with your right eye and open your left eye. D. Look at the eyepiece with your left eye and open your right eye.
2. The microscope has three eyepieces: 5×, 10×, 16×, and the objective lens: 10×, 40×. The maximum magnification of this microscope is.
3. The correct way to remove dust from microscope lens should be wiping.
4. The image of the object "F" displayed under the microscope is "".
5. When Xiaohong did the experiment of making starch from green leaves under light, the methods and steps were all carried out according to the requirements of textbooks, except that two pieces of small black paper were not fixed on the leaves of geranium with paper clips, but the whole leaves were glued together with two pieces of small black paper from the upper and lower sides.
Please answer: The experimental results show that after the whole leaf is dripped with iodine solution, does the part covered with (1) black paper turn blue? (2) Does the part not covered with black paper (but stuck with broadband transparent glue) turn blue? The reason is.
Summary: After food enters the gastrointestinal tract, it can also be hydrolyzed by salivary amylase secreted by pancreas, and the formed glucose is absorbed by the small intestine wall and becomes a nutrient substance of human tissues. Partial hydrolysis of amylopectin can produce a mixture called dextrin. Dextrin is mainly used as food additive, glue, paste, and in the manufacture (finishing) of paper and textiles.
Moss value of knowledge points in the first volume of biology in senior two.
The bryophyte value of the first volume of the second grade biology shows that bryophytes grow in clusters and seats, and there are many gaps between plants. Therefore, they have a good function of soil conservation and water storage.
The role of bryophytes in nature is mainly manifested in the following aspects.
Bryophytes are pioneers of nature.
Many bryophytes can secrete a liquid, which can slowly dissolve the surface of rocks, accelerate the weathering of rocks and promote the formation of soil, so bryophytes are also pioneers of other plants.
2. Moss can turn swamp into land.
Bryophytes, such as sphagnum and wet moss, have strong resistance to water and humidity and grow and breed in lakes and swamps. Their aging plants or their lower parts gradually die and rot and sink to the bottom of the water. After a long time, plant residues will accumulate more and more, so that bryophytes will continue to develop to the center of the lake and swamp, the clear water area of the lake and swamp will continue to shrink, and the bottom of the lake and swamp will gradually rise. Finally, lakes and swamps will become land.
3. Indicating function of bryophytes
Many kinds of bryophytes can be used as indicators of soil pH. For example, the soil with white fur and golden fur is acidic; The soil where moss grows is alkaline soil. In recent years, people regard bryophytes as monitoring plants of air pollution. For example, bryophytes acuminata and squamous bryophytes are particularly sensitive to SO2 in the atmosphere.
Summary: Some bryophytes have the function of storing a large amount of water, such as large water storage cells in sphagnum leaves, which can absorb up to 20 times their own weight of water.
Digestion and absorption of biology test questions in grade one of junior high school
First day digestion and absorption, health, as far as individuals and families are concerned, is the basic element of survival. Only when people are physically and mentally healthy can they ensure the quality of life and its improvement.
1. The human digestive system consists of digestive tract and digestive glands.
2. The sequence of food passing through digestive tract is mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus.
3. The human digestive glands include:
(1) Salivary gland-secretes saliva, and salivary amylase can preliminarily digest starch (starch maltose).
(2) Stomach gland-secretes gastric juice, which can preliminarily digest protein.
(3) Intestinal glands-secrete intestinal juice, which can digest sugar, protein and fat.
(4) Pancreas-secretes pancreatic juice and can digest sugar, protein and fat.
(5) liver-secretes bile, does not contain digestive enzymes, and can emulsify fat. (largest digestive gland) 4. The main organ (or part) that digests food and absorbs nutrition is the small intestine.
5. The main reasons why small intestine is suitable for digestion and absorption are (1), (2), (3) and (4).
(1) The small intestine is the longest in the digestive tract.
(2) There are many folds on the inner surface of the small intestine, and there are many villi on the surface of this structure, which greatly increases the inner surface area of the small intestine, thus increasing the area for digesting food and absorbing nutrition;
(3) The villi of small intestine are thin, and there are abundant capillaries in the villi of small intestine, which is beneficial to the absorption of nutrients;
(4) The digestive juice (including intestinal juice, pancreatic juice and bile) in the small intestine is the most abundant, which is beneficial to the full digestion of food.
Conclusion: Through health education, the scientific knowledge of prevention and treatment of common diseases and frequently-occurring diseases is popularized to the general public, and different people gradually understand and master how to develop a healthy lifestyle.