Questions about proteins biology masters .

You're talking about heavy metal:

Copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, molybdenum, gold, silver, etc.

Heavy metal ions are, of course, ions formed by the loss of electrons from heavy metals, such as:

Cr6+, U6+, Te3+, CO3+, SE6+, Pu3+, Hg2+, Mn4+, Cu2+, PB2+, etc.

The following paragraph is an excerpt from my chemistry elective book (typed it myself):

When the protein is heated to a certain temperature, it will irreversibly coagulate, and after coagulation, it cannot be dissolved in water, and this change is called denaturation. In addition to heating, proteins can be denatured under the action of ultraviolet rays, X-rays, strong acids, strong alkalis, salts of heavy metals such as lead, copper, mercury, and some organic compounds such as formaldehyde, alcohol, and benzoic acid. After the denaturation of the protein, it not only loses its original solubility, but also loses its physiological activity.

Heavy metals refer to metals with a specific gravity greater than 5, (generally referring to metals with a density greater than grams per cubic centimeter), there are about 45 kinds, such as copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, molybdenum, gold, silver, etc. Although heavy metals such as manganese, copper, and zinc are trace elements needed for life activities, most of the heavy metals such as mercury, lead, cadmium, etc., are not necessary for life activities, and all heavy metals are toxic to the human body if they exceed a certain concentration.

From the salting out principle: the solubility of a protein in an aqueous solution is determined by the degree to which the hydrophilic groups around the protein form a hydration film with water, as well as the case that the protein molecules are charged. When a neutral salt is added to the protein solution, the affinity of the neutral salt for water molecules is greater than that of the protein, so the hydration film around the protein molecules weakens or even disappears.

At the same time, after the neutral salt is added to the protein solution, due to the change of ionic strength, a large amount of protein surface charge is neutralized, which leads to the reduction of protein solubility and the aggregation and precipitation of protein molecules.

Salting out 1Salting out generally refers to the process of adding inorganic salts to the solution to precipitate dissolved substances. For example, the process of condensing proteins by enriching (NH4)2SO4.

2.After adding some inorganic salt solutions to some protein solutions, the proteins can be coagulated and precipitated from the solution, which is called salting-out.

3.Animal fat or vegetable oil and sodium hydroxide are stirred and heated in a saponification pot in a certain proportion, and the high-grade fatty acid sodium, glycerol and water formed after the reaction form a mixture. Add salt particles to the pot, stir and let stand to separate the sodium of advanced fatty acids from glycerin and water, and float on the liquid surface.

This reaction is used to make soap) from.

Aluminum ions, copper ions, mercury ions, lead ions, gold ions, silver ions. Affects the activity of heavy metals that cause protein denaturation.

CN ions.

In the case of the landlord, silver ions, gold ions, lead ions, mercury ions, copper ions, and iron ions will cause significant denaturation of proteins, while others are relatively insignificant. However, it should be noted that after the concentration in the protein salt solution reaches a certain level, the protein will be precipitated due to salting-out, but this is different from the principle of heavy metal precipitation protein. Heavy metals denature proteins by forming coordination bonds with proteins, while the former destroys proteohydration membranes.

Because the anion is negatively charged, it is the same as the charge carried by the protein, so it will not cause damage to the protein hydration membrane. It is mainly cations that act as precipitating proteins.

The activity of common proteins is susceptible to the influence of heavy metal ions, and according to this, it is easy to know that iron, copper, mercury, lead, gold, and silver ions should be selected.

If you don't count strong acids, strong alkalis and heavy metal ions, only urea, alcohol, acetone and other organic substances remain, and there are generally no anions that can change the activity of proteins.

In addition, salting-out does not alter all the properties of the native protein, including the original biological activity.

Copper ions, mercury ions, lead ions, gold ions, silver ions because these are heavy metals that denature proteins.

Ask your biology teacher.

Select all. Proteins are the structural and functional substances of living organisms.

a embodies the characteristics of a structural substance.

B protein is the basis of life, so B is right.

c. The role of hemoglobin.

The role of D enzymes.

The role of e antibodies.

Select all. AB is easy to be, C hemoglobin transports oxygen and carbon dioxide.

D enzymes and peptide hormones.

e antibodies.

The second question is A, after the mRNA enters the cytoplasm, it binds to the ribosome. tRNA carrying amino acids synthesizes peptide chains on ribosomes by complementary pairing with bases on mRNA. There are three anticodons on each tRNA and these three bases can be complementarially paired with the codons on the mRNA, which is synthesized in the nucleus with one strand of DNA as a template, so.

The base number of DNA: the base number of mRNA: the number of amino acids in the protein = 6:3:1 so 65*6=390, it should be noted that the number of bases on the mRNA calculated here does not include the stop codon.

The first question, choose D. Dipeptides are produced by the dehydration and condensation of two molecules of amino acids.

Therefore, the chemical formula of the molecules of the two amino acids produced is C8H16N2O6 minus C3H7NO2 of C3H7NO2 to obtain the molecular formula of another amino acid, C5H9NO4

Subtract the part except the R group, C2H2NO2

The chemical formula of the R-based group is C3H5O2. Pick D

In fact, there is a very simple way.

As follows: each amino acid will contain an amino group, so each amino acid has an N dipeptide and two N atoms, then, the R group of the amino acids that make up the dipeptide does not contain N excluding options A and B.

One product is alanine, which contains three C's according to the designation, and the general formula for another amino acid molecule containing five C's amino acids is R-C2H4NO2, according to the conservation of the elements in the chemical reaction

So there are three C's in the R group. So also pick the last one I hope it will help you

Question 1 d

Since it is a dipeptide, one H2O is added after hydrolysis

That is, the total chemical formula is C8H16N2O6

The general formula of amino acids is H2N-CH-Cooh R, and from the cyanamide (R-group is -CH3), we can know that C3H7NO2 and the chemical formula of C5H9NO4 of Cyanamide acid

Subtract the element that removes the R group on the general formula, leaving C3H5O2

Question 2: A 65 amino acids, there are 65 * 3 codons, and 195 codons correspond to 195 * 2 bases on the gene, which is 390

The first question is based on the title, after hydrolysis, it is equivalent to C8H14N2O5+H2O, that is, C8H16N2O6, the chemical formula of melamine is C3H7NO2, so the chemical formula of M is C5H9NO4, and its R group is C3H5NO2, so choose B

Question 2: Translating an amino acid gene requires three bases, and since the genes are paired, the base number should be 65 3 2 = 390

You lack conditions for this question, and you haven't given what the pH value of the solution is, so you can't do it.

Answer. m-n+z。

Process: A protein potato matrix molecule composed of m amino acids, containing n peptide chains, then the number of water molecules required for the complete hydrolysis of this protein molecule is m-n, and because there are z of which are cyclic polypeptides, z water molecules must be added, so the number of water molecules required for the complete hydrolysis of this protein molecule is m-n+z.