What are the feeding methods of the silkworm in biological experiments?
Normally, silkworms mainly fed on mulberry leaves. Under normal feeding conditions, wild silkworms were only willing to feed on mulberry leaves or artificial feed containing mulberry leaves. However, it has been found that through gene editing methods (such as using genetic modification and gene editing methods such as Crisper/Cas9 to obtain a pure mutant of the GR66 gene), the feeding habits of silkworm can be changed. Mutant larvae can no longer eat mulberry leaves, but can also eat apples, pears, corn, soybeans, peanuts and even bread and other foods that wild silkworm refuses to eat. Mutant fifth instar larvae are no longer picky, and can eat mulberry leaves and other foods indiscriminately. However, in conventional biological experiments, if the normal feeding habits of silkworms were studied, the method of providing mulberry leaves or artificial feed containing mulberry leaves was often used. Read more exciting novels for free
What are the methods of biological effect experiments related to space weather?
The biological effects related to space weather were tested as follows: 1. ** Establishing a simulation experiment platform and adopting a space-based technology platform **: Building a simulation experiment platform on the ground based on the physical characteristics of space weather factors, and using aircraft such as space stations, spaceships, recoverable satellites, biological rockets, and high-altitude balloons as space-based technology platforms to carry out experiments. 2. ** Choose a variety of research objects **: Mammal cells, model animals, plants, microorganisms, aquatic organisms, etc. are used as research objects to carry out experimental research on the sensitivity and adaptability of organisms at different research levels such as molecules, cells, tissues, individuals, populations, and ecological systems. 3. ** Using a variety of research methods **: Using a combination of experimental research and statistics to study the impact of space weather on the ground population, model animal modeling research at the cosmic ray observatory, and investigation and analysis of the solar activity cycle and the incidence of diseases related to the ground population. 4. ** Establishment of a specific biological experimental technology platform and analysis and testing methods **: Establishment of a ground-based simulation biological experimental technology platform and related analysis and testing methods for space weather factors in a weightless environment. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Biological experiments, observing biological cells
The following steps and precautions were needed to observe biological cells in biological experiments: ** I. Preparing Work ** 1. ** Prepare the specimen ** - For observing plant cells, he could prepare specimens such as the lower surface of broad bean leaves, plant root tips, onion skin, etc. For animal cells, he could prepare specimens such as frogs, mice, and human cells such as oral cells, red blood cells, nerve cells, bone cells, etc. 2. ** Instrument preparation ** - Light microscope (self-prepared) or hand-held microscope. If you want to use a light microscope, you need to place the microscope properly and light it. For some special observations, such as using the Echo Rebel upside-down microscope, there was no need to equip a computer. The iPad Pro was small and light enough to display the image. It could also be placed in the incubator for observation, and it was wireless connected to the iPad for easy operation. ** 2. Observation process ** 1. ** Plant Cell Observation ** - Taking the surface cells of broad bean leaves as an example, one could observe the crescent-shaped guard cells and irregular surface cells. In the middle of the guard cells were stomata, which were the channels through which gas passed when plants carried out photosynthesis and breathing. The root tip cells in the root tip of the plant were relatively regular, like small rectangular grids densely arranged. Plant cells had a cell wall on the outside, a cell membrane on the inside, and a variety of structures such as vesicles, plastids, and nuclei. 2. ** Animal Cell Observation ** - Frog cells had no cell walls, and they absorbed oxygen from the air through their skin cells while keeping their skin moist. The human oral cavity was composed of irregular flat and hexagonal cells. The nerve cells were divided into two parts, the cell body and the process. The cell body was a hexagonal bulge that was intertwined like a tree root. The human bone cells had many types, such as flat oval bone cells with many bulges, contracted bone cells, short cylindrical or cubic bone cells, multi-nuclear bone cells, and so on. ** 3. Cell State Judgment and Analysis ** 1. ** Medium related (for cell culture)** - Pay attention to the color of the culture medium. Most of the culture medium contains an acid and base indicator. If it is slightly acidic, it will appear yellow, and if it is slightly basic, it will appear purple. When the pH-value changes greatly, it is necessary to consider whether the culture medium is contaminated, the cells are growing too densely, the cells are dying too much, or the concentration of CO2 in the incubator is adjusted. If the culture medium becomes turbid, it may be contaminated or the cells are growing too densely. 2. ** Cell shape and growth state ** - The cells in suspension culture were in a clustered state, while the cells in attached culture were in a free state. Before operating the cells in the ultra-clean bench, if the cells were cultured in conical flasks or petri dishes, it was best to observe the cell growth under the 40x objective lens of the inverted microscope. By observing biological cells, one could understand the structure and function of cells, as well as the differences between different biological cells. These observations would help to understand the law of life activities of living things. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Kitten feeding methods and precautions
Kitten feeding methods and precautions are as follows: ** 1. In terms of feeding ** 1. **0 - 2 months of milk feeding ** - Milk powder selection: The priority is to choose the cat milk powder with guaranteed quality, followed by goat's milk. When limited by objective conditions, it can be replaced by low-glucose milk such as Shuhua milk, but not high-glucose milk such as cow's milk. - Feed tools and methods: It is best to use a special bottle for kittens to let the kittens suck their own milk. If not, they can also be fed with a syringe. When feeding, the concentration should be appropriate. Feed once every 2 - 3 hours, about 5 ml each time, and the temperature should be slightly hot on the back of the hand. Let the kitten lie down properly and feed it from the front at a slight angle (no more than 30 degrees). If the kittens are picky about the taste of milk, consider changing the milk. Don't force the kittens when they don't eat. 2. **1.5 - 3 months of food adaptation period ** - Food selection: At this stage, the digestive system of kittens is still weak. It is suitable to feed softened food. The kittens can be fed after being softened with low-sugar milk (to be soaked thoroughly). It is not recommended to feed the kittens with water. - Feed amount: The kittens can eat and drink until they are 80% full. Follow the principle of eating less and eating more. Feed them about six times a day. The amount of food can be flexibly adjusted according to the growth situation. 3. **3 - 6 months of normal eating period ** - Food choice: You can start to feed kittens directly or make cat food according to the recipe. However, due to the lack of development of the digestive system, you still have to pay attention to the amount and quality of food. ** 2. Excretion ** - For kittens who cannot take care of themselves, use a damp cotton swab or towel with suitable temperature every day to gently wipe the excretory system 3 - 4 times, 5 - 8 times each time to stimulate their defecation. The milk cat might not exhale immediately after every stimulation, but it had to continue every day. Milk cats had less feces. As long as they could keep urinating, their excretory system could theoretically be considered normal. ** 3. Sleep ** - Kittens were more likely to wake up at night than adult cats. After the kittens are 7 - 8 weeks old, they can increase their daytime activity by playing with them. A quiet and safe place for the kittens to rest. If dinner is provided more than a few hours before bed, the kitten may wake up hungry in the middle of the night. It is recommended to arrange the last feeding before the kitten goes to bed and leave a small amount of food. ** 4. Other precautions ** - During the process of feeding kittens, the kittens that had been soaked in milk should not be fed with cold leftovers. - Don't feed raw milk or goat's milk because it has a high level of glucose, which can easily cause diarrhea. - If the kittens need to keep warm, adjust the temperature according to their age (such as 29.0 - 32.0 ° C at 1 week old, 26 ° C at 2 weeks old, 24 ° C at 3 weeks old, 21 ° C at 4 weeks old). Use a towel to separate the hot water bag or electric blanket. Often help the cat turn over, and have a large space for them to keep warm so that they can leave the heat source when they feel hot.
Cat feeding methods and precautions
The feeding methods and precautions for cats at different stages were different: ** 1. Kitten feeding ** 1. **0 - 2 months old ** - If you are breast-feeding, you need to observe if there are kittens that can't get milk. If you can't get milk, you can supplement goat milk powder. - At this stage, the kittens 'stomachs were fragile, and the temperature of the milk was strictly required. The suitable temperature was about 38.6°C (the same as the female cat's body temperature). If it was too cold, it would stimulate the kittens to vomit, cause low body temperature, slow down the intestinal movement, and restrain the absorption. If it was too hot, it would burn the oral cavity, esophagus, and gastric mucus. Before feeding, it can be dripped on the back of the hand to confirm the temperature. When heating, it can be heated over water and stirred constantly. If you want to brew milk powder, you can first brew a day's worth of cold storage, and then take out an appropriate amount to heat up when feeding. 2. **2 - 5 months old ** - You can use dry food to moisten the food, such as choosing small cat food suitable for kittens. - They should be fed 4 - 5 times a day and pay attention to nutritional balance. Kittens have a high demand for protein, vitamins, fat and other nutrients. - It could be supplemented with canned food. - The food provided could help them smoothly transition from drinking milk to eating food, preventing vomiting and diarrhea due to stomach discomfort. 3. **4 - 8 weeks (weaning transition period, if available)** - The main food was the soft cat milk cake + pet goat milk powder. - Can supplement pet probiotic bacteria to help digestion and absorption, cream/nutrition cream to enhance immunity. - Pay attention to keeping warm, eat less and eat more, and replenish water in time. 4. **8 - 12 weeks ** - At the age of 8 weeks, they have the desire to eat hard cat food on their own and can be weaned. ** 2. Cats 6 - 7 months old ** - He fed her three times a day. ** Cats over 3 - 7 months old ** - He fed them about twice a day. ** 4. Pregnant or lactational female cats ** - Feed 3 - 4 times a day, pay attention to the reasonable nutritional content. ** 5. General considerations ** 1. ** In terms of diet ** - Milk was not recommended because most kittens were lactose-intolerant and prone to diarrhea. - It is forbidden to feed cats with human food. The nutritional composition and proportion of human food are not suitable for cats, and some of the ingredients contained in human food are not beneficial to the health of cats. - Due to the special physiological structure of cats, they do not sweat and their kidneys are fragile. They cannot be fed with food containing salt, otherwise, hair loss and even illness may occur. - It is recommended to drink cold boiled water and change the fresh water regularly every day to prevent the growth of bacteria. 2. ** In terms of environment and health ** - Choose a suitable cat, understand the characteristics of the breed, choose a cat that matches your personality and needs, and obtain a cat from a reputable pet shop or adoption center. - Make sure your home is safe. Close your windows and balcony, and clean up potentially dangerous items such as small objects, ropes, and poisonous plants. - Prepare daily necessities such as cat litter boxes, cat food (choose high-quality cat food with high protein), water bowls, cat nests, toys, etc. - Clean the litter box every day, comb the cat's fur, clean its ears, and trim its nails regularly. - Take the cat to the veterinarian regularly for health checks and inoculations. It is recommended to complete the necessary inoculations before 16 weeks and consider sterilization. - He had to know the nearest vet clinic and emergency contact information to deal with emergencies. - To build a relationship with a cat, one must be patient and loving. Respect the cat's personality and spend time with the cat every day to play and interact.
Cat feeding methods and precautions
The following are the cat feeding methods and precautions: * * 1. Method of feeding ** 1. * * Feed frequency ** - Kittens: Feed them 3 - 4 times a day. - Adult cats: Feed them twice a day. It is best to feed the cat within 7 - 8 minutes. 2. * * Food Selection ** - * * Cat Food **: - Choose the right cat food according to the age of the cat, because different growth stages have different nutritional requirements. - Choose safe cat food and avoid toxic cat food. Pay attention to the color of cat food (cat food with sufficient nutrition is usually brown or dark brown) and avoid eating cat food that contains excessive amounts of chemicals. - You can choose a cat food that contains a patent probiotic (such as BC30 probiotic), high quality animal protein (such as 83% high quality animal protein), crude protein greater than 40%, and no grain starch (low carbon water, low gi). - * * Water **: - Clean water was provided, just enough. Don't give the cat tap water. Fresh cold water is better and should be changed frequently. In winter, when cats don't like to drink water, they can choose to use a constant temperature water dispenser or a yogurt machine with a constant temperature function to provide water. - * * Milk products **: - Cats can't completely digest the sugar content in milk, so don't give cats a lot of milk. You can choose pet milk powder or an appropriate amount of Shuhua milk. - Fruits and Vegetables: - Although the fiber in fruits and vegetables helped with the digestive system, cats should not be given too much, nor should they use fruits and vegetables as their main source of food for a long time. You can also use a vitamitamin tablet for pets instead of eating fruits and vegetables to supplement vitamins. - * * Other Food **: - The cat can be fed with goat milk powder (according to the ratio of 1:6 warm water, the feeding amount can be doubled according to the pet's weight, during pregnancy and breast-feeding), freeze-dried chicken (ready-to-eat, can be mixed with staple food, as a snack reward feeding, can also be soaked in water to feed) and other supplementary nutrients. 3. * * Special feeding ** - If the cat's stomach is sensitive and there is a disorder of the intestinal flora, you can choose a probiotic cat food to help regulate the stomach. - When changing food, you should follow the 7-day food exchange method. At the same time, you should eat it together with pet probiotic to avoid the cat's stomach discomfort. * * 2. Points to note ** 1. * * Avoiding harmful food and items ** - Don't feed cats with too much starch or cat food with high starch content because cats lack starch in their bodies. Digesting a large amount of starchy food will increase the burden on the liver. - Chocolate, coffee, various medicines, cleaners, pesticide/mothballs and other items at home should be stored well to prevent cats from eating them by mistake. Plants that are harmful to cats, such as lilies, should also be kept away from cats. 2. * * Keep food fresh and utensils clean ** - Leftover food would rot and breed bacteria after being placed, so fresh food should be replaced in time, and tableware should be cleaned and disinfected. It was recommended to choose ceramic or glass bowls for cats. They should not be too deep so that they would not have black chins. 3. * * Other aspects ** - When you bring a new cat home, you must create a safe environment for the cat. Don't be in a hurry to play with it. Let the kitten familiarize itself with the environment first and take the kitten to the feeding basin and the litter box. - The cat litter should be evenly spread in the litter box with a thickness of about 3 - 5cm. After defecation, shovel out the agglomerated part and replenish it. It is recommended to change the cat litter every two weeks. - To bathe a cat, use a pet shower gel. Follow the correct method of use to avoid cat skin problems. - If there were other kittens in the house, the newborn kittens would be isolated for at least three days. Pay attention to the temperature and humidity of the cat's living environment. Try to let the cat bask in the sun for 1 - 2 hours every day. Don't take the cat out for the first week. Don't let the cat sleep on the floor to prevent catching a cold.
300 words reflection summary of biological experiments
Biological experiments were an important means to explore the mysteries of life. Through experiments, one could deepen their understanding of biological knowledge. During the experiment, there were many points worth reflecting on. In terms of operating skills, he was not familiar with the use of some experimental instruments. For example, the operation of the microscope, the steps such as focusing and focusing were prone to mistakes, affecting the efficiency and effect of observation. In the use of reagents, sometimes the dosage and order of addition were not well grasped, which reflected the lack of understanding of the experimental principle. There were also problems with the experimental design. Some experiments lacked rigorous control settings, resulting in the results being unconvincing. Moreover, when designing the experimental steps, sometimes the control of variables was not fully considered, causing the results to be affected by interference factors. In terms of experimental attitude, there were situations where he was not careful and patient enough. For example, in the cell observation experiment, some details of the cells were neglected because of the eagerness. In the future, more attention should be paid to operational specifications, in-depth understanding of principles, careful design of experiments, and correct attitude in order to improve the quality and effect of biological experiments. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What are the precautions for doing biological experiments?
The following are some things to note in biological experiments: - ** Selection of materials ** - In the experiment to observe the distribution of DNA and R A in cells, the materials used were the oral cavity cells or the onion inner skin cells (colorless). Purple onion skin cells or mesophysical cells could not be used to prevent color interference. - In the experiment of detecting reducing sugar in biological tissues, the experimental materials were required to be white or light-colored, and the content of reducing sugar was high. Green leaves, watermelons, blood, and other materials could not be used to prevent color interference, nor could potatoes (containing starch), sugar cane, or sugar beets (containing sugar cane) be used. - ** Experiment Operation ** - In the experiment of observing the distribution of DNA and DNA in cells, a slow flow of water was used to prevent the cells on the slide from being washed away. - In the experiment of detecting reducing sugar in biological tissues, the identification of reducing sugar was the only thing that needed to be heated, and it must be heated in A water bath. It could not be heated directly with an alcohol lamp. If it was not heated, there would be no brick red deposit. Non-reducing sugar (such as cane sugar)+ Fehling reagent (heated in a water bath), the phenomenon was light blue (the color of copper dioxide). Fehling reagent needed to be mixed and used immediately. Biuret reagent needed to be added separately (add solution A first, then add solution B). - In microscopic observation experiments, one had to follow the principle of first using a low power scope before using a high power scope. The magnifying power referred to the magnifying power of the length. The shorter the eyepieces, the longer the objective lens. The closer the objective lens was to the slide, the greater the magnifying power. - In the fat identification experiment (the only experiment that required a microscope to detect reducing sugar, fat, and protein in biological tissues), the effect of 50% alcohol was to wash away the floating color. - ** Reagents ** - In the experiment to observe the distribution of DNA and R A in cells, 0.9% NaCl-solution (normal salt solution) was used to maintain the normal shape of oral cells;8% sulfuric acid was used to change the cell membrane penetration, accelerate the dye to enter the cells, and separate the DNA and protein in the embryos, which was conducive to dyeing; and the methyla-green pyronine dye solution was mixed and used immediately. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Pet cat breeds and feeding methods
Common pet cat breeds included American Shorthair, British Shorthair, Orange Cat, Cow Cat, Siamese Cat, Dragon Li, Scottish Fold, Persian Cat, Ragdoll Cat, Russian Blue Cat, Norway Forest Cat, British Hairless Cat, Sphinx Cat, Maine Coon, etc. The feeding method was as follows: 1. ** Feed frequency **: Young cats usually need to be fed at least four times a day; adult cats only need to be fed once a day. 2. ** Feed amount **: The amount of food should be determined according to the pet's age, size, activity, and temperament. You can refer to the instructions on the food packaging or consult a veterinarian. In order to increase the variety of food and protect the health of the pet's teeth, canned food and dry feed can be combined or fed in turn. Probiotic bacteria can also be used to prevent indigestion. 3. ** Dietary control **: The average cat will consume the amount it needs, but it is still necessary to pay attention to not indulge the cat to eat. Obese cats are prone to health problems. In addition to controlling the amount of food, it was also necessary to prepare toys for the cat to play and exercise. 4. ** Type of food **: Although cats are more selective about food, cats should be allowed to eat cat food that is suitable for them. Many cat foods on the market now can provide balanced nutrition and satisfy their delicious needs. To avoid letting cats develop a partial eclipse habit, they should not only feed the cat's favorite food. Delicious food on the table could easily make the cat no longer like balanced cat food and may eat too much. 5. ** Drinking water **: Water is very important to cats. Clean drinking water should be prepared in the cat's water bowl at all times, especially in hot weather. This can prevent cats from drinking water from the toilet bowl or looking for water everywhere. 6. ** Special treatment (for special breeds)** - ** Long-haired cats (such as Persian cats, Norway Forest cats, etc.)**: Thick and long hair, needs to be combed daily and trimmed regularly. - ** Hairless cats (such as Canada hairless cats, Sphinx cats, etc.)**: No fur protection, special needs for temperature and skin care, provide a suitable warm environment, and clean the skin regularly. - ** Double-furred cats (such as Maine Coons, Scottish Folds, etc.)**: Thick fur, requires more frequent combing and care. In addition, it was necessary to provide a suitable space and activity environment for the cat to stretch and move. It was necessary to take the cat to the veterinarian regularly for physical examination and prevention. It was also necessary to spend time interacting with the cat every day to give love and care.
What are the methods of biochemical analysis technology experiments?
There were many methods for biochemical analysis experiments. The following were some common methods: 1. ** Separation Technique **: - ** Absorption column **: Separates different substances by using the difference in the absorption force of the sorbant. For example, when the mixture flows through the stationary phase composed of the sorbent with the mobile phase, different components will have different moving speeds due to different absorption and detachment conditions, and finally achieve the purpose of separation. Commonly used sorbants were silica gel (suitable for the separation of neutral and acidic substances, such as acids, sugar, fats, etc.), aluminum dioxide (suitable for the separation of neutral and basic substances, such as antibiotics, steroids, vitamins, and acids), and activated carbon (including powdered activated carbon, Granular activated carbon, and different types of polyamide-activated carbon). - ** Separation column **: Separates substances based on the different distribution coefficient of each component in the mixture in two incompatible liquids. The distribution coefficient is the ratio of the solute concentration in the two solutions when the concentration reaches equilibrium. Different substances have different distribution coefficient. At a certain temperature, it can be reflected by the distribution coefficient formula (Kd = C2/C1)(Kd is the distribution coefficient, C2 is the concentration of the substance in the stationary phase, and C1 is the concentration of the substance in the mobile phase). - ** Ion Exchange Separation **: Separation is achieved based on the difference in affinity of ion exchanging agents for different ions. - ** Gel-Based Separation **: Separation is carried out according to the molecular sieve effect of the gel. Small molecules can enter the interior of the gel, while large molecules are excluded, so that molecules of different sizes in the mixture can be separated. - ** Affinity Purification **: Separation using the specific affinity between biological molecules, such as the specific binding between an antigen-to-an antibody-and-a substrate-to-an ester-specific binding. 2. ** Spectral method **: This is a commonly used method in biochemistry experiments. It has the advantages of high sensitivity, simple operation, and speed. The principle was that the solution of many substances had a selective absorption of light. Different substances had different absorption abilities for different frequencies of light due to different molecular structures, forming a unique absorption spectrum. The absorption spectrum of a substance can be used to identify the substance, and its content can be determined according to the degree of absorption of a certain wave length of light. The Lambert-Beer law,[LCKT = -lgT]([T] is the degree of light transmission,[K] is the absorption coefficient,[C] is the concentration, and [L] is the thickness of the liquid layer) is the basic principle of this method. 3. **Western Blot **: It is a commonly used experimental method in molecular biology, biochemistry, and immune genetics. It can be used to detect the expression level of a specific protein in a sample. The basic principle was to color the cell or biological tissue samples processed by gel eletrophoresi with specific antibodes. By analyzing the position and depth of the staining, the information about the expression of specific protein in the cell or tissue was obtained. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The addition principle of the independent variable in biological experiments is
The addition principle was a principle to control the independent variables in a controlled experiment. Compared with the normal state, it artificially increased certain influencing factors. In other words, the purpose of the experiment was to find out what the result of a certain variable would be. At this time, the independent variable was known, but the dependent variable was not. When determining the control experiment using the addition principle, the group with independent variables was the experimental group, and the group without independent variables was the control group. For example, the experiment to verify that hydrogen Peroxide-based compounds could accelerate the decomposition of hydrogen Peroxide-based compounds used the " addition principle ". <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>