Biological Experimental Design, Urgent !! 15

Experiment Title: Observe the structure of seeds.

Objective: To understand the structure of seeds.

Experimental instruments and equipment: blades, magnifying glasses, droppers.

Subjects and Materials: Macerated bean seeds, macerated corn seeds.

Experimental Methods and Procedures (1).

Observe the structure of Phaseolus vulgaris seeds.

1. Take a grain of macerated soybeans and observe its shape.

2. Peel off the outermost layer of thin skin of the seed - seed coat, divide.

Open and close the two ** leaves.

3. Identify cotyledons, radicles, germs and embryos against textbooks.

shaft, and look closely with a magnifying glass to see what features each of them has.

Experimental method step (2).

Observe the structure of corn seeds.

1. Take a piece of macerated corn seed and observe its appearance.

2. According to the position of the dotted line in the illustration of the textbook, use a blade to cut the corn seed longitudinally from **.

3. Drop a drop of diluted iodine wine on the profile, and then use a magnifying glass to carefully observe the endosperm dyed blue by iodine wine and the peel and seeds, radicles, hypocotyls, and cotyledons dyed blue to see what characteristics they have.

4. Pick up the corn cotyledons with a needle. On closer inspection, it was found that the corn seed had only one ** leaf.

Conclusions of the experiment. The germ of the seed can develop into a plant body in the future.

The main component of endosperm is starch.

Phaseolus vulgaris seeds have two ** leaves.

Corn seeds have only one leaf.

Let's just bacteria.

Equipment: test tubes, droppers, incubators, petri dishes, strains, inoculation rings, microscopes, sterilizers, etc.

Reagents: several strain solutions, acidic buffers, alkaline buffers.

Steps: 1. Sterilization.

2. Inoculation and grouping.

3. Control external variables (temperature, pH).

4. Cultivate for the same long time.

5. Observations.

6. Draw conclusions.

Effect... If the range is too large, you should consider narrowing down the scope of the influence, such as the mouthfeel, the consistency of the yogurt, etc.

Otherwise, what kind of measurement?

Biologically, the fat is tested with Sudan or Sudan dye, which will have different colors for milk with different fat content (of course, the color can only be observed in the microscope), the darker the color, the higher the fat content.

Specific steps: mark three glass slides, add the same amount of milk with different fat content dropwise, cover the coverslip, stain with Sudan dye (temporary loading should be done, specific), microscopic observation, color can be.

1.Raw egg whites are made into egg drop liquid.

2.Water hydrochloric acid.

3.The fact that the substances in test tube A do not change, and the substances in test tube B change (disappear), indicating that gastric juice has a chemical digestion effect on protein under suitable external conditions.

Answer: 1. Material treatment: weigh 50g of radish and cut it into pieces, add 30ml of water, crush it with a crusher, and filter the homogenate through gauze.

2. Extraction: 1. Add 10% NaCl to the filtrate obtained by gauze filtration until the precipitation is precipitated. Filter through the filter paper, put the precipitate on the filter paper into the test tube, add 1 ml of distilled water, shake, and use for protein identification.

2. In the filtrate to remove the protein, add 95% alcohol, stir gently with a glass rod, see that there is a white flocculent precipitate, filter through the filter paper, and place the flocculent precipitate on the filter paper on the glass slide with tweezers for DNA identification.

3. Identification and results:

1 In the test tube used for protein identification, add biuret reagent to produce a color reaction, and at the same time, put the protein standard sample and 1ml of distilled water into another test tube, and add biuret reagent to produce a color reaction. It was observed that the color in the two test tubes was basically the same, indicating the presence of protein in the test tube.

2 On the glass slide used for DNA identification, add methyl green stain dropwise, and the DNA appears blue-green, indicating that the white flocculent precipitate is DNA.

3 Through the detection of the homogenate of white radish storage roots, it was indicated that there were proteins and DNA.

4. Discussion: 1 It is a structural component of biological membranes such as cell membranes, components of functional proteins such as enzymes, and components of stored proteins such as aleurone grains.

2 Nucleus.

I don't know how this answer is, but if you think it's okay, please set it to the best.

1. Material treatment: The white radish is crushed with a crusher, and the radish juice in the crusher is filtered to obtain the clarified radish juice, which is prepared into a 10% NaCl solution with distilled water and NaCl, and the protein standard sample is dissolved to obtain the solution.

2. Extraction: (1) Take an appropriate amount of radish juice in a test tube, add an appropriate amount of 10% NaCl solution, shake evenly, and let it stand for a period of time to dissolve the precipitate. (2) Take the same amount of dissolved solution and protein standard sample dissolved solution into test tubes A and B respectively, and remove an appropriate amount of (1) medium clarification solution in test tube C.

3. Identification and results: (1) Add the same amount of biuret reagent dropwise to test tubes A and B, and compare the colors of the two; Add dropwise 95% alcohol to tube C. (2) If the color of test tube A and B are the same (or not much different), then there is protein in the tissue cells of the radish storage root; If the color is different (or very different), there is no protein in the tissue cells (3) There is no flocculent precipitation after adding 95% alcohol dropwise to test tube C, then there is no DNA in the tissue cells; If there is a precipitate, the precipitate is made into a tablet, and the methyl green staining solution is added dropwise, if it is blue-green, there is DNA in its tissue cells, and if it is not blue-green, there is no DNA in its tissue cells.

4. Discussion: (1) Protein plays a role in the tissue cells of radish storage roots, which stores the amino acids required for the growth of radish roots, and is a component of the cell membrane (2) Nucleus.

1. Place the roller at the highest point on the right first.

In the process, you will find that the speed of the rolling pendulum is getting bigger and bigger, and the position of the rolling pendulum is getting lower and lower until the lowest point, indicating that the gravitational potential energy can be converted into kinetic energy, and then after the lowest point, you will find that the speed of the rolling pendulum is getting smaller and smaller, and the position is getting higher and higher, indicating that the kinetic energy can be converted into gravitational potential energy.

2. First find a plane (desktop) to fix and compress the spring to a certain degree x1, put the small wooden block on one end of the spring (not fixed) and then release the spring, observe and record the distance of the small wooden block bounce off, and then the same, recompress the spring x2 (x2>x1), observe and record the distance of the small wooden block bouncing open twice, and prove that the greater the elastic deformation degree, the greater the elastic potential energy according to the energy conversion energy.

3. Place the tuning fork in the water first, and then tap the tuning fork after the level is still, and observe the fluctuation of the water while hearing the sound, indicating that the sounding body is vibrating.

4. Connect the circuit first, place the small magnetic needle around the energized solenoid, turn on the power supply, and observe that the pointing of the small magnetic needle is arranged according to a certain law, and the arrangement of the small magnetic needle around our bar magnet is the same, so it can be explained.

5', take a certain amount of water in the test tube heated to boiling after the water vapor produced through a beaker of water, and wait for all the water in the test tube to become water vapor in the beaker after measuring the temperature of the water in the beaker; Another spoon that takes an equal amount of boiling water and pours another person with boiled water and then stirs to measure the temperature of the water, and it can be concluded by comparing tltz.