A reward of 50 points will be awarded for the explanation of the phenomenon of the junior high schoo

Now I have 5 substances.

1.Liquid bread. (The ingredients are starch, protein (less), fat, no reducing sugar) iodine wine is blue, dropping diurea light purple, Sudan three orange, this drop reagent has no obvious phenomenon.

2.Fruit juice (..)(The composition is starch-free, there is a small amount of protein, and the main reducing sugar) iodine wine has no obvious phenomenon, there is no obvious phenomenon in dropping diurea, Sudan three has no obvious phenomenon, and Benedict reagent water bath heats brick red precipitate. ）

3.Egg whites and milk contain protein, and the biuret reagent appears purple phenomenon.

4.Edible oil contains fat, which is dyed orange by Sudan.

The above you gave is a mixture, the composition is not clear, it is best to try it.

The bread definitely contains starch, and iodine will turn blue.

Fruit juice contains reducing sugars, so Benedict reagent (Benedict) should refer to Filin reagent, right? There will be brick-red precipitates when heated.

Sudan three is to test edible oil, plus Sudan three will have orange-red reflection, remember it must be this orange red, write wrong no points, by the way, plus Sudan four orange.

Milk egg whites, protein, plus biuret reagent is purple reflected.

I hit it by hand, and I came from junior high school as a biology adult, I hope it, thank you

Junior high school biology is this.,Speechless.。。。

Liquid bread can be detected with iodine, and it is beer. Because most countries or regions have added auxiliary raw materials such as corn, rice, sucrose, wheat, starch, fruit, honey and other ingredients to beer. Starch and elemental iodine turn blue, so beer can be detected with iodine.

Fruit juices are tested with Benedict reagent because Benedict reagent detects reducing sugars, which are found in fruit juices. Benandi reagent (Benedict) is produced by brick-red precipitate when it encounters reducing sugars. Milk and egg whites are, of course, tested with biuret.

Biuret turns purple when the protein is met (can be heated in a water bath). As for distinguishing between egg whites and milk, you definitely will!! The final cooking oil was tested with Sudan III.

1) Clear water. Animal cells are observed to have normal saline.

2) To be dissected.

3) Tear the epidermis with tweezers using the method of tearing the piece.

4) The loading should be removed from the microscope, the microscope should be put back in the box, and the experimental equipment should be "back and forth from where".

5) When taking oral epithelial cells, you can use a toothpick to gently scrape a few times on the oral cavity, and the residue on the toothpick is the oral epithelial cell, and then the residue on the toothpick is coated on the glass slide, and then the remaining preparation operation is completed.

6) The microscope should be lowered to a minimum with a coarse collimation spiral.

7) It's better to prepare in advance, just foolproof!

8) Concentrate on the experiment, and the teacher will not embarrass you. Most of the students should have high grades.

Don't be stressed, it's easy. That's how it all came by. It won't be strict.

How many things, and no score!!

It's too wide, so you can buy this exercise and do it yourself.

Seven on 1Pasteur experiment (are microorganisms produced by the broth itself or entered by air) 2Microscope 3

Observe the structure of the leaf 4Observe the structure of animal and plant cells5**Paramecium stress 6

Verify that green leaves make starch under light as a raw material for photosynthesis8Respiration of seeds 9Prost.

The difficulty of the experimental operation process of the junior high school biology examination is very low.

It's super easy, I took the test at the beginning.

1: Use a microscope, adjust the light distance, and see the words inside (you will be given a small piece of paper) 2: Cut corn, drip iodine, change color, and point out the structure There are two more I don't remember, but it's also very simple.

There are also experiments that are divided into steps, which is actually very simple.

There are also teachers who will send you an outline in advance to teach you how to do it.

1.Ask the question: Is betel nut harmful to the human body?

2.Make an assumption: betel nut is harmful to the human body.

3.Develop and implement a ** program: 10 monkeys were divided into two groups, group A was fed 3 betel nuts per day, group B did not do any treatment, and other conditions remained the same. After 3 months, the monkey was given a physical examination.

4.Expected results: Group B was healthier than Group A.

5.Cause analysis: It usually occurs slowly after chewing betel nut for a long time, or smoking paper cigarettes and smoking buckets.

Oral leukoplakia is a precancerous change.

In fact, from the biopsy, some leukoplakia cells are mature and neatly arranged, which is benign.

However, in some cases, the degree of malignancy is not much different from that of carcinoma in situ.

Outwardly, oral leukoplakia is not easy to distinguish between benign and malignant, so it should be biopsied and, if necessary, preventively excised.

The damage to mice can also be tested, if you want to say what harm is there to the human body, it is impossible to use people as experimental materials, right?