High school biology constitutes amino acid peptide bond problem

The amino acids that can form the peptide chain must be amino acids, so it is necessary to see if there are amino acids and how many of the 5 compounds given first.

Obviously, only three are amino acids. 2 is 2 ethanolamine and 4 is diaminopropionic acid, neither of which is an amino acid. A molecule of tripeptides can be formed.

The condition is that each amino acid must be used and that each amino acid should be used only once. This condition must be met, otherwise it will be impossible to judge.

Let's look at the amino and carboxyl groups of the three amino acids. 1 has 1 amino group and 1 carboxyl group, both of which can be used to form peptide bonds; 3 has 1 amino group and 2 carboxyl groups, and no matter how they are arranged (no matter where they are located in the tripeptide), there will be at least 1 free carboxyl group; 5 has 2 amino groups and 1 carboxyl group, and no matter how they are arranged, there will be at least 1 free amino group.

When the amino acids in the tripeptide are arranged according to 1 3 5, the carboxyl group of 1, the amino group and carboxyl group of 3, and the amino group of 5 are used to form peptide bonds, and the number of peptide bonds is amino group, carboxyl group of 3 and carboxyl group of 5, and the distal amino group is free. There are 2 free amino groups and 2 free carboxyl groups. i.e. select c,2,2,2.

When the amino acids in the tripeptide are arranged according to 5 3 1, the amino group of 1, the amino group and carboxyl group of 3, and the carboxyl group of 5 are used to form peptide bonds, and the number of peptide bonds is carboxyl group, 3 carboxyl group and 5 amino group, and the distal amino group is free. There are 2 free amino groups and 2 free carboxyl groups. It is also the choice of c,2,2,2.

When the amino acids in the tripeptide are arranged according to 5 1 3, the amino and carboxyl groups of 1, the amino group of 3, and the carboxyl group of 5 are used to form peptide bonds, and the number of peptide bonds is 2 carboxyl groups and 5 of 2 amino groups are free. There are 2 free amino groups and 2 free carboxyl groups. It is also the choice of c,2,2,2.

There are 3 other permutations, which are 5 1...

No matter how they are arranged, the peptide bonds are always 2 and there are always 2 amino and 2 carboxyl groups free, so always toSelect C,2,2,2

All are amino acids because they all conform to the general formula of amino acids. Because the protein has a peptide chain, there is 1 amino group and 1 carboxyl group, and then look at whether there is an amino group and a carboxyl group on the R group, there is 1 carboxyl group on 3 and 1 amino group on 5 in the figure, so the amino group of the protein composed of amino acids is 2 and the carboxyl group is 2. Since there are 3 amino acids that make up a protein, the number of peptide bonds is 3-1=2.

So the answer is c.

The answer is cFirst, the amino acids that make up proteins refer to the amino acids with amino and carboxyl groups attached to the same carbon atom, i.e., 1, 3, 5 in the figure

Then, the calculation of amino and carboxyl groups in the peptide chain is 1 free amino group (or carboxyl group) at one end of the peptide chain, plus the number of amino groups (or carboxyl groups) in the R group, therefore, the ammonia number of the peptide chain in this question is 1+1 (the amino group of R group in 5) = 2, the carboxyl number is 1+1 (the carboxyl group of R group in 3) = 2, and the number of peptide bonds is 2

The dehydration and condensation of amino acids in the cell is the process of forming peptide chains and then further forming proteins, while ribosomes are the only place where proteins are synthesized, so the dehydration and condensation of amino acids in cells is only carried out on ribosomes. Whereas, peptide bonds are formed during the dehydration and condensation of peptide chains.

Many biochemical reactions to form biological macromolecules are formed by the formation of water condensation, taking the formation of the most common protein as an example: the carboxyl group (-COOH) of one amino acid molecule is linked to the amino group (-NH2) of another amino acid molecule, and at the same time loses one molecule of water, this combination is called dehydration condensation. 2 amino acid molecules form a peptide bond by dehydration condensation, 3 amino acid molecules form two peptide bonds by dehydration condensation, and so on, 10 amino acids will form 9 peptide bonds;

So imagine that if 10 amino acids form two peptide chains, how many peptide bonds will be formed? Just like there are 10 students lined up, if you line up in a line, there will be 9 intervals in the middle, if 10 people are divided into two teams, every 5 people in a team, there will be a few intervals, obviously there are 8, in the same way, if 10 amino acids form two peptide chains, 8 peptide bonds will be formed, and so on, you will summarize the formula of "the number of peptide bonds formed (the number of water molecules removed) = the number of amino acid molecules - the number of peptide chains".

(1) The chemical name of the substance can be called tripeptide, containing 2 peptide bonds, its basic unit is amino acid, and the basic unit structure is H2N-CHR-Cooh, which is combined with each other in the way of dehydration and condensation, and is connected by peptide bond chemical bond, and the structural formula is -NH-CO-.

To do this kind of polypeptide problem, first find the peptide bond, that is, -nh-co-, count how many peptide bonds, this question has 2 peptide bonds, then this polypeptide is formed by the dehydration and condensation of 3 amino acids, the name is tripeptide).

2) When the substance compound is formed, 2 water molecules are generated, and there are 2 kinds of hydrolyzed products, and the hydrolyzed products are called amino acids.

Because every water molecule between amino acids is removed, a peptide bond is formed, and there are 2 peptide bonds in this question, so 2 water molecules are generated, and the hydrolysate is broken from the middle of the peptide bond-nh-co- to form an amino acid, and there are 3 amino acids in this question, but it can be seen that the first amino acid is the same as the third amino acid, so there are 2 kinds of hydrolysate).

3) In this compound, there is 1 amino group, and its expression -NH2 is written, and 2 carboxyl groups are written, and its expression -COOH is written.

Amino-NH2, carboxy-COOH, look for it in the figure, just count how many)

(1) Tripeptide Two peptide bonds Amino acids r Dehydration condensation peptide bonds -Co—NH-

h2n－c－c00h

h(2) two two amino acids.

3) 1 x NH2 and 2 -cooh

peptides; two peptide bonds; -conh-;This basic unit is combined with each other in a dehydrated condensation manner, and the heart peptide bond chemical bond necklace.

3；Amino acid;

3: 2 pcs. 1 pc.

There was a mistake upstairs.

1. Tripeptide, 2, amino acids, CH3-CH2(-R)-COOH, dehydration condensation, peptide bonds, -Co-NH-, 2 [note the types with duplicates], amino acids, -NH2, 2, -COOH

The first is the general formula of the structure of amino acids: H

nh2─ccooh│r

This is the same as organic chemistry

COOH: carboxyl group.

NH2: amino group.

R: side group, in different amino acids, "r" is also different, in other words, "r" determines the type of amino acid.

The "base" here refers to the functional group.

Whereas, a peptide bond is an HH between two amino acids

nh2─ccooh──

nh2─ccooh││

rr─cooh

In combination with NH2, I remove a part of H2O and become.

CO NH, that's the peptide bond.

A peptide chain is a long chain formed by the dehydration and condensation of x amino acids like above, and when one or several peptide chains are folded (like a wire is folded into a ball), it becomes a protein.

Spatial structure is the folding and combination of one or several peptide chains that make up a protein.

Pure hand-played,The copied wood has a small jj,LZ can ask again if you don't understand anything.。

1. When amino acids are dehydrated and condensed into peptide chains, it is assumed that five amino acids are dehydrated and condensed into a peptide chain, 4 water molecules are removed, plus 1 peptide chain number, which is five, that is, the number of amino acids. If there are two such peptide chains, 8 water molecules are removed, and the number of two peptide chains is 10, that is, the number of amino acids.

2. Every time a water molecule is removed, a peptide is formed, so the number of peptide bonds = the number of water molecules removed.

3. When every two amino acids are dehydrated and condensed, one NH2 and one COOH will be lost, so there is at least one NH2 and one COOH in a peptide chain (at least because there may also be in the side chain group R).

4. From 1, the number of amino acids = the number of peptide bonds + the number of peptide chains.

5. The total molecular weight of the protein is the total mass of the amino acids that make up it, but because of the dehydration and condensation, the mass of the removed water should be subtracted

Another: The questioner's formula is wrong, the average molecular weight of amino acids is calculated by an-18 (n-m).

It's very simple, several amino acid molecules are condensed to form n-1 molecule water and a peptide chain, this peptide chain contains a molecule-NH2 and a component-cooh, for example, there are 10 amino acid molecules to form 3 peptide chains, then the number of water generated is 10-3=7.

To put it simply, the number of amino acids - the number of peptide chains = the number of peptide bonds = the number of dehydrated molecules, and the number of free amino or carboxyl groups contained at least = the number of peptide chains.

Protein molecular weight = number of amino acids * average molecular weight of amino acids - number of dehydrated molecules * 18. You're talking about the formula in letters. I just know how to memorize these formulas, I used to learn this and found it difficult to learn, but then it was better.

There are also exams, which are generally the first one.

A peptide bond is a chemical bond formed by dehydration and condensation between the amino group of an amino acid molecule and the carboxyl group of another amino acid molecule. Because the condensation product is called a peptide, it is called a peptide bond.

Note that this amino group must be an amino group on top of the amino acid. Amino groups on other parts (R-groups) are not counted.

Peptide bond composition.

I learned it in the compulsory stage of chemical bonds. If it is a textbook before the revision, it belongs to the compulsory two chemical bond topics.

In high school chemistry, when learning about organic matter, there are proteins, starches, fats, chemical properties and molecular formulas. A peptide bond is the process by which multiple amino acids are dehydrated to form a peptide chain up to a protein.

Compounds formed by amino acids linked by peptide bonds are called peptides.

1. Amino acids are a class of organic compounds containing amino and carboxyl groups. Amino acids are one of the many bioactive macromolecules that build biological organisms, and are the basic materials for building cells and repairing tissues. The cavity is absolutely lost.

2. It is used by the human body to make antibody proteins, hemoglobin, enzymes and hormones to maintain and regulate metabolism, and is the source of all life.

3. Amino acids, peptides and proteins are the basic components of organic life tissues and cells, and play a pivotal role in life activities.

4. In addition to forming proteins, some amino acids also participate in some special metabolic reactions and show certain important characteristics. Peptide is an organic compound formed by dehydration of amino acids, containing carboxyl and amino groups, is an amphoteric compound, and is a bioactive substance involved in a variety of cellular functions in living organisms.

Classification and application of peptides:

1. It is mainly divided into medical peptide drugs, peptide antibiotics, vaccines, agricultural antimicrobial peptides, feed peptides, cosmetics for daily chemicals, soybean peptides for food, corn peptides, yeast peptides, and sea cucumber peptides.

2. From a functional point of view, it can be divided into: antihypertensive peptides, antioxidant peptides, cholesterol-lowering peptides, opioid active peptides, high F-value oligopeptides, food strong taste peptides and so on.

3. Active peptides are closely related to nutrition, hormones, enzyme inhibition, immune regulation, antibacterial, antiviral, and antioxidant. Peptides are roughly divided into: peptide drugs and peptide health products.

4. Traditional peptide drugs are mainly peptide hormones, and the development of peptide drugs in 2011 has been greatly developed to various fields of disease prevention and control, especially in the following fields.