In the first few minutes of self-study, almost all the books downstairs were picked up.

At this time, Niu Zihao and Li Min were sitting next to each other. He learned from the cloaked man that Li Min was one of the members of the Star of Xueba.

If that's the case, it's all your own.

The star of the top student is related to physics, that is, every discipline should have its own corresponding star of the top student. No one knows this yet, but Li Min is the first star of the top student, which has long been an indisputable fact.

As for the light bulb pattern on his chest, Niu Zihao didn't think it was very strange. In physics, it's not surprising that there's a light bulb as a sign.

Like Edison's attempt to study tungsten filaments in light bulbs, he failed many times. From this story, we can learn from his perseverance. In fact, failure is not terrible, what is terrible is that you don't have the courage to face failure.

Failure is a successful mother, isn't this phrase very commonly used?

Although school was only ten minutes early, those who studied seriously continued to read the book for ten minutes, and then packed their schoolbags and went home.

In the classroom, there are only two people left, Li Min and Niu Zihao.

"Let's go, go back to the dormitory and get some sleep." Niu Zihao looked at Li Min, who was still racking his brains to solve the problem, and said by the way.

"It's okay, it's still early for me to go to bed, do you want to continue studying" Li Min only cares about reading, which is quite admirable, if he can't figure out a question, he feels very uncomfortable. It wasn't until the solution was successfully solved that the joyful excitement arose.

"If you want to study on your own, then I'll leave first, if you go a little later, the landlord will probably lock the door, and then I will be alone, and I can only sleep on the streets."

"So that's the case, then don't go tonight, come to my dormitory, there is 24-hour free Wi-Fi, it's really good." As he spoke, Li Min took out a key from his trouser pocket, "Look, this is on the door of my dormitory." ”

When he saw the key, Niu Zihao was relieved. Then is this a matter of not returning home at night, probably not? The first time you hear this word, you will be associated with bad people. But his night tonight is related to studying.

"Niu Zihao, let's take a look at this biology question together, and go back to the dormitory when we're done." It seems that Li Min is experiencing some difficulties, and Niu Zihao must help him.

Niu Zihao took the mock test paper, only to see that it was written: In May 1982, the Shanghai Institute of Biochemistry of the Chinese Academy of Sciences synthesized a drug with analgesic effect and not addictive to patients like morphine - enkephalin.

Because it's really complicated, it can't be drawn, but it doesn't affect the fluency of the solution.

The picture is finished, and I answer accordingly:

(1) What is the chemical nature of enkephalin? What are the structural characteristics of its basic constituent units?

(2) If the length of the enkephalin peptide chain remains unchanged, the type and number of amino acids that compose it remain unchanged. can change its properties.

(3) Enkephalin is only effective when injected subcutaneously, but cannot be taken orally, what is the main reason?

(4) If enkephalins are completely hydrolyzed, do they need water molecules? What are the hydrolyzed products? Seed.

(5) Enkephalin available? Reagent identification, presentation? color, the reason for which is contained in the compound? A color reaction occurred with this reagent.

Niu Zihao glanced at it, and then began to analyze the answer directly.

(1) From the analysis of the figure, enkephalin is composed of five amino acids, so its chemical nature is pentapeptide. The basic units that make up polypeptides are amino acids.

(2) The structure of polypeptides is related to the types, numbers and order of amino acids that make up polypeptides.

(3) Peptidases in the digestive tract can break down polypeptides into amino acids.

(4) As can be seen from the figure, the molecular structure of enkephalin contains 4 peptide bonds (-CO-NH-), so 4 molecules of water are required for hydrolysis. Of the 5 amino acids obtained by hydrolysis, two of them are the same (H2N-CH2-COOH), so there are 4 kinds of hydrolyzed products.

(5) There are peptide bonds in the polypeptides, which react with the biuret reagent to produce a purple complex.

In less than five minutes or so, Niu Zihao quickly finished answering this question.

"Now you can go!"

"Uh-huh."

The two of them closed the doors and windows, and walked through the silence of the night. The shadow of the moon is shining, hanging above the dome like a bittersweet one, and the poignant colors are always shrouded in the top of the campus all year round, how beautiful it is.

After leaving the school gate, they began to live a free life. Keep continuing the stone road to the right, and walk towards the alleyway with the green garden community. With the help of dim street lamps, you can vaguely see the words engraved on the walls of the alley, and there are some recruitments and advertisements for buying real estate.

"Classmate, do you want to have a baked rice cake, one yuan and two." The uncle who was drinking at the mouth of the alley saw someone coming and hurriedly said.

Li Min habitually waved his hand, fried things like barbecue, girls like to eat the most. For example, his tablemate Xie Monroe often eats this for breakfast.

Li Min also tried to persuade her a few times, girls, sometimes they are really stubborn. It's okay, just like it.

In front of a small buying department, the two of them stopped.

Li Min went into the store and bought a few bottles of drinks, a bag of melon seeds, and a few bags of snacks. "We'll all have to celebrate tonight, because you're the first bosom friend I've ever made."

"Friend, can we really do it, it's been a few weeks since school started, and you only know me, so don't you dislike my status as the last in the class?" After Niu Zihao listened to what he said, he also felt that Li Min was ranked 7th in this monthly exam, and his single subject score physics was among the best in the whole grade. To make friends with such people, to be honest, the pressure is really bigger than the mountains.

And Li Min sighed deeply, it is indeed not easy to make friends, and it is even more difficult to find a confidant. Like Cheng Biting Tie, he tricked himself into going to the toilet to find a book, then he was not worthy of being his friend at all, this kind of person would hide far away when he saw it in the future, and it would be dangerous to save people. For this reason, Li Min has always held a grudge.

"Of course, but are we friends for a year or three years?" Li Min opened the bag of melon seeds and grabbed a handful of them for Niu Zihao.

"Needless to say, I know that you are a science student, and I also study science, and this homeroom teacher is a geography and liberal arts, so we will leave in a year. In my opinion, only the first eight of the top ten classes are science classes, while the first and second classes are the most powerful classes. "Speaking of which, Niu Zihao actually secretly sweated for Li Min, he has to work harder if he wants to get into a powerful class." The first and second classes are all top 140 students in the high school entrance examination, so it is estimated that there are not many people who study liberal arts, so it is not easy to get in. ”

"It's okay, all we can do is work hard, and leave the rest to Providence."

While munching on melon seeds, the two were chatting. And just passing by, you can always hear a few dog barks behind you.

After a while, the two of them walked in from a place called Pioneer Alley and disappeared into the darkness of the night.

A relatively spacious landlord's house, a few bicycles parked in the courtyard, at first glance, are rented students. Li Min's room is in a corner on the third floor.

Stepping on the treads of the iron staircase, the sound of "boasting" should be so pleasant.

"It's coming!"

"Hmm."

Seeing that a girl was pouring water that had just washed her hair at this time, Li Min stepped forward to say hello. The girl was a student at the nearby No. 5 Middle School, and sometimes she would often ask Li Min a few questions, and over time, the two of them got to know each other.

When I opened the door, I was greeted by the smell of garbage. It smells like a few days ago.

"The room is so messy, you don't plan to clean it up." Niu Zihao's house is actually even more chaotic than this, but he is embarrassed to say it.

"It's messy, it's not messy, when I was in junior high school before, it was even more messy than this." Li Min smiled, "This is normal, aren't all boys like this?" ”

Niu Zihao glanced at the surrounding environment, his clothes were still soaked in the basin, and several pairs of socks were piled up next to the bed.

Overall, the most books in Li Min's room are still the most. It's no wonder that he studies so well and keeps books in his hand. Even the mobile phone he uses is the kind of vivo mobile phone that costs hundreds of dollars, and if you want to download a "Glory of Kings" to play, it is estimated that it will be stuck.

"What, you're eating instant noodles at home, too?" Seeing that there was half a box of spicy Master Kang's braised beef noodles under the bed, Niu Zihao asked curiously.

"Of course, this is for emergency use, in case one day the gas runs out, or you are too lazy to cook, then instant noodles will come in handy."

Thinking really thoughtfully, Niu Zihao just smiled and didn't speak.

"Don't say it, as soon as I mention instant noodles, I suddenly get hungry, it just so happens that I didn't eat tonight, and now it is estimated that the school cafeteria has already been off work, there should be no food. The restaurants outside are also closed, so let's use Meituan to take out orders on our mobile phones. ”

"Okay, I'll transfer the money to you when it's over."

"No need, they're all friends, I'll invite you this time, and you'll invite me again next time, so that the two of us will be even." Li Min said as he downloaded the Meituan takeaway app on his phone.

But Li Min's appearance of rubbing the net surprised Niu Zihao, who has been rubbing the net all year round, is this rubbing to a new height?

I saw Li Min immediately take off his shoes, stand on top of the bed, and hold his mobile phone high above his head. This situation is very similar to the Statue of Liberty in New York, USA, but people are holding torches, while Li Min is holding a mobile phone.