The second year of biology experiment to raise silkworms
The following is an example of raising silkworms in the second year of biology: ** 1. Purpose of the experiment ** By raising silkworms and observing the growth and development process of silkworms, they could understand the characteristics of complete metamorphosis. ** 2. Experiment Equipment ** Scissors, writing brush, silkworm rearing tools, silkworm eggs, mulberry leaves, magnifying glass, paper box, cotton paper, etc. ** 3. Experimental Steps ** 1. ** Silkworm egg hatching stage ** - ** Prepare the incubation environment **: - A layer of tissue paper was laid at the bottom of the paper box, and some small holes were pricked on the lid to ensure air circulation. Put the silkworm eggs in a paper box and place them in an environment with a temperature of about 26 ° C and a humidity difference of 3 - 4 ° C (it can be adjusted according to the actual situation. Generally, it is more suitable in the warm season at the end of spring). The room can be shaded, and the next morning, light exposure can promote the hatching of small silkworms (ant silkworms). - Observing the changes of the silkworm eggs, the silkworm eggs were light yellow when they were just laid, flat oval, about 1.3 mm long. During the hatching process, the color of the silkworm eggs would gradually change from light yellow to yellowish-brown, and finally to purple-black. - ** Treatment of the newly hatched silkworm **: The newly hatched silkworm is black, thin, small, and has fine hair. 2. ** Silkworm Rearing Stage ** - ** 1st and 2nd instar silkworms **: - The first and second instar silkworms had to be fed with chopped, fresh, tender mulberry leaves. When changing mulberry leaves, you can use a brush or feather to move the silkworms. The temperature of the feeding environment was maintained at 26 - 26.5 ° C, with a difference of 3 - 4 ° C between humidity and humidity. - The characteristics of silkworm dormancy: Before silkworm dormancy, the amount of food consumed will be reduced, and excrement may be discharged. The color of the body will darken and look a little yellow, and there will be the phenomenon of not eating or moving, and the head will be raised high. After hibernation, the silkworm will shed its skin. When it shed its skin, the front half of its body will lie down, and the whole body will move in waves. Then, the new skin will be exposed, and the whole body will crawl forward to get rid of the old skin. Finally, the old head shell will fall off by shaking its head. - ** Silkworms of 3rd instar and later **: - After the third instar, the silkworm's body grew up and could be fed in a large box. The mulberry leaves did not have to be all young leaves. The mulberry leaves were given 3 - 5 times a day. - From the newly hatched silkworm to the fifth instar silkworm, it shed its skin four times. Every time it shed its skin, the silkworm would grow a little bigger. The third or fourth instar silkworms could be observed. Their bodies were about an inch long and grayish white. They were divided into three parts: the head, the chest, and the abdomen. The head was very small, with mouthparts for chewing mulberry leaves, a pair of antennae, and six single eyes on each side of the head. There were three pairs of chestlegs on the chest, a pair of stomachs on the sixth to eighth segments of the abdomen, a pair of tail legs on the tenth segment, and a tail horn on the back of the eighth segment. There were nine pairs of spiracles on the chest and abdomen for breathing. - ** Fifth Inch Silkworm **: At the fifth instar, the silkworm's body is oily and translucent, and it begins to spin silk. At this time, they can be placed on the straw handle to make cocoons. 3. ** Pupa Stage ** - The cocoon was taken ten days after spinning, and the cocoon shell was cut open to observe the pupa. The pupa was brown, spindle-shaped, divided into three parts: chest and abdomen. The head had antennae, the chest had three pairs of feet and a pair of wing buds, and the abdomen was divided into sections. 4. ** Adult (Silkworm Moth) Stage ** - Ten days later, the pupa turned into a moth and broke out. It can be observed that the female moth's abdomen is swollen, and the antennae are gray and comb-shaped; The male moth's abdomen is slender, and the antennae are black and feather-shaped. Both the female and male moths have wings. Silkworm moths lay eggs after mating and die after giving birth. ** 4. Observation and Record ** During the whole experiment, it was necessary to observe and record the time, shape, color, size and other characteristics of each growth stage of the silkworm, such as the color and shape changes of the silkworm eggs at different stages of hatching, the physical characteristics and behavior habits of the silkworm at different ages (such as sleeping, silking, etc.), the shape of the silkworm pupa, the appearance characteristics of the silkworm moth, and the difference between male and female. At the same time, the four stages of the silkworm could also be made into specimens for further observation. The methods of making specimens were as follows: dry storage of eggs, blowing-drying of larvae, soaking of pupas in 5% formalin, and air-drying of moths on wing-spreading plates (refer to more detailed specimen preparation materials). Read more exciting novels for free
Chenghai Biology Experiment Operation Test
On May 26 - 27, 2015, the Chenghai District Education Bureau organized the relevant middle schools to conduct the junior high school biology experiment operation assessment. The teaching station and the teaching and research section formed an inspection team to inspect the assessment work of each school, focusing on the examination room preparation, organization work, and the proficiency of the students. The main contents of the assessment included observing the onion scale leaf inner skin cells, tomato pulp cells, human oral cavity cells, and the structure of the leaves with a microscope. The cells of the lower surface of Chinese kale leaves and the leaves of wall moss. There was no more information about Chenghai Biological Experiment Operation Test, so he could not answer accurately. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The Writing Method of High School Biology Experiment
High school biology experiments usually included the following important parts: ** 1. Experiment Title ** The main content of the experiment should be clarified, and the core content of the experiment should be summarized concisely, such as "exploring the effect of temperature on the activity of the enzyme". ** 2. Experiment Purpose ** 1. ** Knowledge target ** - Explain the biological knowledge concepts to be understood or verified through experiments, such as "understanding the principle of the effect of temperature on the activity of an enzyme". 2. ** Ability Target ** - He explained the skills to be trained during the experiment, such as "mastering the application of the variable control method in the experiment, learning to use specific experimental instruments for measurement and observation", etc. ** 3. Experiment Principle ** 1. ** Biological Principles ** - Explain the basic biological principles that the experiment is based on. For example, in the experiment of "Observing the plasmatic separation and recovery of plant cells", the principle is that the protoplasma layer of plant cells is equivalent to a semi-transparent membrane. When the concentration of cell fluid is lower than the concentration of the external solution, the cell loses water and plasmatic separation occurs. When the concentration of cell fluid is higher than the concentration of the external solution, the cell absorbs water and plasmatic separation occurs. 2. ** Principle of related technology (if any)** - If special technical means were involved, such as dyeing techniques, the principle must be explained. For example, in the experiment of "Observing the distribution of DNA and DNA in cells", the affinity of methy-green and pyro red stains for DNA and DNA was different. methy-green made DNA appear green, and pyro red made DNA appear red. ** 4. Experimental Materials and Tools ** 1. ** Experiment Materials ** - List the biological materials used, including the types and parts of the organisms. For example, in the experiment of "Observing the Mitosis of Plant Cell", the materials were onion root tips (onions, garlic). 2. ** Experiment Tools ** - Write down in detail the required instruments, reagents, etc., such as microscope, slide, cover glass, disintegration solution, gentian violet dye solution, etc., and indicate the necessary information such as the concentration of the reagent. ** 5. Experimental Steps ** 1. ** Preparing Stage ** - This included the pre-treatment of the experimental materials, such as the cultivation of onion root tips in "Observing the mitosis of plant cells"(3 - 4 days before the experiment, place the onions on a wide-mouthed bottle filled with water, the bottom of which is in contact with the water. The device is placed in a warm place, and pay attention to changing the water frequently. The purpose is to prevent the roots from rotting. Wait until the roots grow to 5 cm). 2. ** Operation procedure ** - Each step of the operation was described in detail in order, including the actions of the operation, the amount of equipment or reagents used, etc. For example, in the experiment of "making and observing the temporary mounting of the onion scale leaf inner skin cells", the rubbing was done.(Wipe the slide clean with a clean gauze, then take a cover glass and wipe it clean. Put the cover glass on one end of the slide for later use.)(Drip 1 - 2 drops of water in the center of the slide with a dropper)(Take a piece of onion scale leaf, cut a small square about 0.5 cm with a blade on the inner skin, and then tear a small piece of transparent film with tweezers)(Dip the peeled inner skin into the water droplets on the glass slide and flatten it with tweezers), cover (use tweezers to pick up the cover glass so that one side of it touches the water droplets on the glass slide first, then slowly put it down and cover it on the material to be observed), dye (then drop a drop of the solution of the solution of 3. ** Points to note ** - During or after each step, the points that needed special attention were indicated. For example, when using a microscope for observation, it was necessary to pay attention to the low power microscope before the high power microscope; when making temporary mounting, it was necessary to keep the experimental materials moist. ** 6. Experiment result ** 1. ** Anticipated result ** - According to the theory and purpose of the experiment, he could deduce the possible results. For example, in the experiment of "exploring the effect of temperature on the activity of an enzyme", if the temperature was within a suitable range, the activity of the enzyme would be higher and the reaction speed would be faster; if the temperature was too high or too low, the activity of the enzyme would decrease, and the reaction speed would slow down or even stop. 2. ** Real-world result (if the experiment has been completed)** - An objective description of the phenomena observed or the data measured during the experiment can be presented in the form of tables, charts (such as bar charts, line charts, etc.), or text. ** 7. Experiment conclusion ** 1. ** Analysis of the results ** - To analyze the experimental results and explain the reasons for the results. For example, in the experiment of "Observation of plasmatic wall separation and recovery of plant cells", the cell structure and physiological mechanism of plasmatic wall separation or recovery were analyzed. 2. ** Come to a conclusion ** - According to the analysis of the results, the final conclusion of the experiment should be summarized. The conclusion should be closely related to the purpose of the experiment, such as "temperature has a significant effect on the activity of the protein. Within a certain range, the activity of the protein increases with the increase of temperature. After exceeding the optimal temperature, the activity of the protein decreases with the increase of temperature." ** 8. Analysis of errors (if any)** 1. ** Source of error ** - Find out the factors that may cause the experimental results to be inconsistent with expectations, such as the accuracy of the experimental instrument, the individual differences in the experimental materials, and human errors in the operation process (such as errors in measuring reagents, etc.). 2. ** Modification measures ** - In view of the source of error, the improvement methods were proposed, such as improving the accuracy of the instrument, increasing the number of experimental samples to reduce the influence of individual differences, and regulating the operation process. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The Skills to Solve Junior Biology Experiment Questions
Junior high school biology experiment questions solving skills are as follows: 1. ** Carefully review the questions ** - Accurately excavate the known conditions and analyze their implications. Find the known information in the questions in an all-round way. When examining the questions, be stable, accurate, and slow. Fully excavate the useful information for solving the questions. Pay special attention to the key and restricted words to avoid the blindness of solving the questions. - For questions that required an "incorrect" or "wrong" choice, mark the negative statement to remind yourself when answering and checking. 2. ** Focus on the situation ** - When doing situation questions, the answers not only had to conform to biological principles, but also to the reality of life and production. 3. ** Organizing your answer ** - Only by clearly understanding the knowledge points could the answers be accurate. - He had to consider the problem from many angles to ensure that the answer was comprehensive. - The answer was concise, clear, logical, and rigorous. - Give priority to using the original sentence in the textbook to answer; when the textbook is not available, carefully organize the language, pay attention to the completeness of the words, avoid "not expressing the meaning" or "answering the question", and read it again after writing to ensure that it is scientific. 4. ** Search for teaching materials ** - According to the knowledge points of the questions, they searched for relevant content in the teaching materials. Although the background of many information questions was new, the knowledge points of the questions were based on the teaching materials. They had to use the keywords in the questions to transform into the knowledge of the teaching materials to solve the questions. 5. ** Experiment Design Questions ** - The soul of the experimental questions was the experimental principle. One had to deeply understand the experimental principle, accurately find the single variable of the experiment, and accurately design the experiment according to the single variable principle, the comparison principle, and the equivalent principle. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What is the meaning of in Situ Observation Experiment in Biology?
In the field of biology, in-place observation experiments referred to experiments that were carried out in the original and real environment of a living creature. For example, when observing the behavior of fish in place, it was to directly observe and record the behavior of fish in their natural habitat without interfering with their natural living conditions, so as to obtain the true behavior patterns of fish in their natural state. In the field of tumor research, the model organism's in Situ Experimental Platform was dedicated to reproducing the growth of tumors in their natural environment. The in Situ Experimental Model allowed tumors to grow in their organs of origin and interact with stroma cells and tissue-specific immune cells, making tumor growth similar to the development of the original tumor. This would help in the study of tumor growth and migration, drug screening and efficacy evaluation, cell therapy and immune therapy research. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Senior High School Biology Experiment on Photosynthesis and Breathing
The following are some of the experimental designs for photosynthesizing breathing in high school biology: ** 1. Using droplet movement to measure photosynthesis and respiratory rate ** 1. ** Device Setting ** - For the measurement of breathing rate: - Use a sealed container to place plant materials (such as leaves or germinated seeds). The container was filled with a solution that could absorb carbon dioxide (such as a solution of NaOx). - The container was connected to a graduated glass tube (such as a U-shaped tube) with a drop of colored liquid in it. - "Principle: Under dark conditions (ensure that only breathing is carried out), the plant absorbs oxygen and releases carbon dioxide. As carbon dioxide is absorbed by the solution, the gas pressure in the container will decrease, and the droplets will move towards the container. The distance (or volume) that the droplet moved in a unit of time could represent the breathing rate (commonly used to measure the breathing rate by the amount of oxygen absorbed in a unit of time). - As for the measurement of the net photosynthesis rate: - A similar device, but the container is filled with a substance that can provide a stable concentration of carbon dioxide (such as a solution of NaHCO3, which can decompose to produce carbon dioxide). - When the device was placed under light, the plants would undergo photosynthesis and breathing. The oxygen produced by photosynthesis would increase the pressure in the container, and the droplets would move away from the container. The distance (or volume) that the droplets moved in a unit of time could represent the net photosynthesis rate (usually expressed as the amount of oxygen released or the amount of carbon dioxide absorbed). - The calculation of the true photosynthesis rate: true photosynthesis rate = net photosynthesis rate + respiratory rate. 2. ** Experiment Notes ** - Variant Control: - Light intensity: If you want to explore the effect of light intensity on the rate of photosynthesis, you can use different power bulbs or change the distance between the bulb and the plant to control the light intensity. - [Temperatures: Different thermostats can be used to control the experiment temperature.] - [Concentration of carbon dioxide: For example, carbon dioxide buffer solutions of different concentration can be used for adjustment.] - Principle of comparison: You can't experiment with just one set of equipment by gradually changing its conditions. Instead, you should use a series of equipment to compare with each other. ** 2. Black-and-white bottle method to measure the photosynthesis and respiratory rate ** 1. ** Operation method ** - Prepare several sets of black and white bottles. The black bottle was wrapped in a black material (so that it was in a dark environment), while the white bottle was normally transparent. - Put an equal amount of plants (aquatic plants such as algae are more convenient) and an equal amount of water in each bottle. 2. ** Principle ** - The plant in the black bottle only breathed, and the measured value was the intensity of the breathing (such as the reduction of oxygen or the increase of carbon dioxide). - The plants in the white bottle were photosynthesizing and breathing under light, and the measured value was the net photosynthesis intensity (such as the increase in oxygen or the decrease in carbon dioxide). - Combining the data of the black bottle and the white bottle, the true photosynthesis intensity value could be obtained (true photosynthesis rate = net photosynthesis rate + respiratory rate. The net photosynthesis rate here is the white bottle data, and the respiratory rate is the black bottle data). ** 3. Half-leaf method to measure the photosynthesis and respiratory rate (half-leaf weighing method)** 1. ** Operation process ** - Choose the leaves of the plant and cover half of them from the light (such as covering them with black paper), while the other half is under normal light. - After a period of time (usually a few hours to a day, depending on the plant species and experimental conditions), the leaves were taken down, and a hole cutter was used to punch out leaf discs of the same area on the light-blocking part and the non-light-blocking part of the leaves. - The leaf discs were dried to a constant weight and weighed. 2. ** Principle ** - The light-blocking part was only used for breathing, and the weight reduction was due to the consumption of organic matter by breathing. - The unshielded part underwent photosynthesis and respiration, and its weight change was the difference between the organic matter produced by photosynthesis and the organic matter consumed by respiration. By comparing the weight changes of the two parts of the leaf discs, the total amount of organic matter produced by photosynthesis could be calculated, and thus the photosynthesis rate (commonly used to measure the photosynthesis rate of field crops) could be obtained. ** IV. Studying the influencing factors of photosynthesis and respiratory rate with the gradient-based method ** 1. ** Device Setting ** - Prepare a series of devices with the same plants in each device. - Different conditions such as light intensity, temperature, or carbon dioxide concentration were set in different devices. 2. ** Purpose * - The effects of light intensity, temperature, or carbon dioxide concentration on the intensity of photosynthesis could be investigated. For example, by setting different light intensity (such as using different power bulbs or changing the distance between the bulb and the plant to set low, medium, and high light intensity), the plant's photosynthesis rate under each light intensity can be measured (the change in oxygen or carbon dioxide can be measured by the droplet movement method mentioned above or other methods), and the relationship curve between light intensity and photosynthesis rate can be obtained. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What are the ways to try and design a cell biology experiment?
Here are some cell biology experiments: * * 1. Cell culture-related experiments ** 1. * * Primary Cultivation Method ** - * * Tissue-block culture method **: Directly remove cells, tissues, or organs from the body and place the tissue block in a suitable culture environment. This method is relatively simple to operate, and the cells are easier to grow. For example, when cultivating cardiac muscle tissue, the beating of the tissue block can sometimes be observed. - * * Digestive culture method **: The tissue is broken down into individual cells by digestive zymes and then cultured. 2. * * Subculture **: When the cells grow to the confluence of a single layer in the primary culture, subculture is required due to space and nutrition constraints. The cells were separated from the original culture vessel and then seeded into a new culture vessel to continue the culture, so as to reproduce more cells and prevent the cells from deteriorating and dying. * * 2. Cell Function Testing Experiment ** 1. * * Cell Growth Detection ** - * * Cell Metabolic Activity Detection (Based on MTT-test, CCK-8, etc.)**: For example, the MTT-test (thiazole-blue) method can measure the activity of the mitochondria by adding a thiazolium-based salt to the cells, thereby reflecting the cell proliferations. 2. * * Cell cycle detection **: Use a specific staining method or technique to determine which stage of the cell cycle the cells are in (such as G1, S, G2, and M). For example, flow biochemistry can be used in combination with the corresponding cell cycle detection reagents to analyze the cell cycle distribution. 3. * * Cell death detection **: - * * morphological observation method **: Observing the changes in the shape of cells through an optical microscope or an electron microscope. Apoptotic cells will show features such as cell contraction, nuclear condensation, condensation of Chromatin, and the formation of an necrotic body. - * * Biochemical detection method **: For example, detecting the activity of Caspase in cells. Caspase is activated during the process of cell death, and its activity can be determined by using specific substances and detection reagents. It can also determine the cell death by detecting the extroversion of PhosphatidylSerine (PS) in the cell membrane. For example, Annexin V-FITL/Pi double staining method can be used. Annexin V can specifically bind to the extroversion of PS, and then combine with Propidium Iodide (Pi) to distinguish early and late cells in the process of cell death. 4. * * Cell invasion and migration experiment ** - * * Cell Scratch Experiment **: Create a "scratch" on a single layer of cultured cells, and then observe the ability of the cells to migrate to the scratch area to evaluate the migration characteristics of the cells. - * * Transwell experiment (cell invasion experiment)**: A special chamber (Transwell chamber) is used. There is a membrane in the middle of the chamber. The membrane can be coated with an extra-cellular matrix component (such as Matrigel) to simulate the extra-cellular matrix barrier in the body. The cells were seeded in the upper chamber, and a medium containing a Chemokine was added to the lower chamber to observe the ability of the cells to pass through the membrane. If the membrane was coated with an extra cellular matrix component, the invasive ability of the cells could be tested. If the membrane was not coated, the migration ability of the cells could be tested. * * 3. Cell structure research experiment ** 1. * * Genetic Analysis Technique **: - When the cell was in the middle of division, the highest degree of condensation of the nuclei was the best time to observe and analyze the shape of the nuclei. Through the analysis of the shape and number of microorganisms, it could be used for clinical diagnosis, research on the genetic basis of infertility and habitual abortion, prevention of the birth of children with abnormal microorganisms, and gene positioning. 2. * * electron microscope technology **: includes scanning electron microscope and transmission electron microscope. It can be used to observe the ultra-structure of cells, such as the shape of the cell surface and the structure of the organelle. * * 4. Special Cell Cultivation Experiment ** 1. * * organ culture **: Special devices are used to allow organs, organ primordium, or parts of them to survive outside the body and maintain their original structure and functions. For example, the organ culture method, the stainless steel metal grid method, the Wolff culture method, and the spread box culture method could be used to observe the interaction between tissues, the differentiation of tissues and cells, and the effects of external factors (including drugs) on tissues and cells. * * 5. Radiation-related experiments ** 1. Autoradiography: A method that uses the photosensitizing effect of the radioactive ionising radiation on the nuclear colloid to display the distribution, quantity, and location of the radiation in the specimen or sample. It could be combined with electron microscopes and biological molecules to study the distribution and metabolism of radioactive substances in tissues and cells. It could also reveal changes in the synthesis of nuclei and damage. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Sichuan Guang 'an High School Entrance Examination Biology Experiment
In the biological experiment of the 2024 Guang 'an High School Entrance Examination, the operation steps were as follows: First, count the experimental instruments, wipe the cover glass and the glass slide with clean gauze, and then put the cover glass on the glass slide for easy gripping; Then, drip clear water in the center of the glass slide, tear off the lower surface of the leaf, and use tweezers to pinch a small piece of leaf skin and flatten it in the clear water; Then, gently cover the cover glass with tweezers and ask the invigilator to check; Then, he took the lens and placed it slightly to the left of the experimental table. He adjusted the light of each structure from top to bottom until he could observe a bright field of vision. Then, he asked the invigilator to check. Then, he placed the prepared mounting slide on the stage, pressed it tightly with a pressing clamp, and turned the coarse focal screw to lower the tube until it was close to the mounting slide. Then, he slowly raised the tube until he found the cell. Then, he asked the invigilator to check. Finally, he removed the slide, restored the microscope (from top to bottom), put the microscope back in its original position, cleaned and wiped the slide and cover glass, and tidied up the laboratory table to end the exam. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What will be the punishment for failing a junior high school biology experiment?
In the Ningde City junior high school graduation biological experiment operation examination, the examination failed, no make-up examination. Moreover, the biology experiment was part of the physical, chemical, and biology test scores in the middle school entrance examination. Although it did not account for much of the score, when the competition was fierce, a small reduction in score would affect the ranking of the test results, which would affect the chances of choosing a school from junior high to senior high. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
High school biology experiment with high magnification lens to observe the plastids
1. ** Experiment Principle **: - The basis for identifying the plastids was that they were green, flat, oval or spherical, and their shape and distribution could be observed with a high-powered microscope. - The plastids in the cellular stroma were not static. They could move under different light conditions. This movement could change the direction of the oval body at any time. It could receive more light without being burned by strong light. Its shape and distribution were conducive to receiving light to complete photosynthesis. For example, the mesophysical cells on the top of a leaf have more plastids than those below, so they can receive more light. 2. ** Experiment Material **: - You can choose the leaves of mosses and black algae. Because these leaves were thin and small, and the plastids were clear, the entire small leaf could be taken to directly produce the film. - If he used spinach leaves as experimental materials, he would take the lower skin of the spinach leaves with a little bit of mesopathy, because the skin cells did not contain plastids. He could also choose vegetables, small vegetables, red amaranth, leeks, carrots, cucumber skins, and other plant materials. 3. ** Experimental Steps **: - Using the black algae as an example, he made a temporary slide of the black algae cells: Take a small leaf of the black algae with tweezers, put it into the water droplets of the clean glass slide, and cover it with a cover glass to avoid excessive bubbles. - Then, he first used a low power microscope to observe, and then switched to a high power microscope to observe the plastids. 4. ** Points to note in the experiment **: - During the experiment, the temporary mounting of the film must always be maintained in a state of water. - The treatment of the film mounting under different light sources: When the light source was strong (200W light bulb), the light bulb should not be too close to the film mounting (it should be greater than 20cm), otherwise the plastids themselves would disintegrate due to burns. Under strong light, the plastids faced the light source with the side of the oval body, while under weak light, the plastids faced the light source with the front of the oval body. The shape of the plastids observed under different light sources was not exactly the same. - What was observed under the microscope was the inverted image of the object. To make the object move up, it was necessary to move down and mount the slide. To make the object move to the left, it was necessary to move the slide to the right. - When observing, one had to find the best reference object (the plastids, which proved the flow of the plasma according to the movement of the plastids), the best position (near the leaf vein, where the cells had sufficient water, and it was easy to observe the flow of the plasma), and the best field of view (relatively dark, which was conducive to identifying the dynamic changes of the object). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Junior high school biology experiment examination operation video teaching
You can search for "High School Biology Experiment Operation Video Collection" in the search engine to obtain the teaching content of the junior high school biology experiment examination video. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>