Biology calculations in high school, biology calculations in high school

The aerobic respiration reaction formula is: C6H12O6 + 6H2O+6O2---6CO2 + 12H2O+ energy, so it inhales 6 oxygen and releases 6 carbon dioxide, and the anaerobic respiration reaction formula is: C6H12O6---2C2H5OH+2CO2+ energy, so it releases two carbon dioxide, and the last aerobic respiration releases six carbon dioxide, adding together is eight, 8:

This kind of problem generally involves 2 formulas: number of peptide bonds = number of dehydration = number of amino acids - number of peptide chains (+1) This +1 is only used when forming a looped chain.

Relative molecular weight of protein = number of amino acids * average relative molecular weight of amino acids - number of dehydration * 18

Then you can substitute these two announcements.

Number of peptide bonds = number of dehydration = 12-1 + 1 = 12 Molecular weight of aminomycin = 12 * 128-12 * 18 = 1320 So choose c

The formula for calculating cyclic polypeptides is: molecular weight = na-18n

Because all the amino and carboxyl groups of the cyclic polypeptide are linked.

He is a cyclic polypeptide, that is, the last one is also dehydrated and condensed with the first amino acid, so there is one more water removed. Therefore, 18 12 is used (do not subtract 1).

So it should be 12 128-18 12 = 1320

Let's start with a simple one, why do you use 18 to multiply? Answer: Because it is dehydrated, H2O, his molecular weight is 2+16=18

2.Why 1320? Answer:

Because if 12 amino acids form a chain polypeptide, 11 water molecules will be removed, but the topic is the formation of a cyclic polypeptide, which can be understood in this way, that is, the head and tail of the chain are connected and then a molecule of water is removed, so the water removed is 11+1. The calculation is 12*128-12*18=1320

Are you satisfied with this explanation, if you don't understand it, ask again!

Let a heterozygous wheat self-cross to obtain f1,f1, and aa:aa:aa=1:

The ratio of 2:1 is to eliminate the plants that are not resistant to rust, i.e., the individuals of AA. Therefore, only 1 3aa and 2 3aa are left, and then f2 is obtained by self-breeding, and only aa individuals will have non-rust resistant plants, accounting for 2 3 1 4 = 1 6.

Test point: The law of gene segregation.

Analysis] When answering such questions, it is easy to confuse the processing of gamete probability in self-breeding and free mating. In fact, in the question, the genotype of the heterozygous wheat is AA, and the offspring 1AA, 2AA, and 1AA are produced by inbreeding, and after the elimination of AA, AA accounts for 1 3 and AA accounts for 2 3, and they are inbred to obtain F2, which is not resistant to rust AA=2 3 1 4=1 6. The combined F2 rust-resistant plants were 1-1 6=5 6.

Method Summary] Free mating means that there is a mating opportunity between each body, that is, all genotypes can be mated, and all the results of their own free mating offspring should be counted together in the case of offspring (the probability of male and female parents is required.

Consider, the probabilities of both sides need to be multiplied). Inbreeding, on the other hand, refers to the combination of male and female gametes on the same body of hermaphroditic organisms, which is limited to the interbreeding of the same genotype, so the offspring only need to count the results of their respective inbreeding (i.e., consider one side.

rate). According to the stem information "heterozygous for rust resistance", it can be seen that the rust resistance of wheat is the dominant trait (denoted by a and a) relative to the non-rust resistance, then the genotype of the heterozygous wheat is aa and the heterozygous wheat (aa) is inbred to obtain F1, then the genotype and proportion of F1 are aa:aa:

aa=1：2：1．

This question examines the law of gene segregation and its application, firstly, it is inferred that rust resistance is a dominant trait from the stem information "heterozygous for rust resistance", and secondly, the key condition of "eliminating plants that are not resistant to rust" in the question is deducted, and then the law of gene segregation is used to answer the question, pay attention to accurate calculation, and avoid mistakes that should not be made

You've been wrong since F2, how did aa account for (2 3) 2 in F2?

Taking only 2 generations of self-inbred as an example, the first self-inbred and then eliminate AA1 3, AA2 3, and if the second self-inbred is not eliminated, AA1 3+2 3*1 4, AA2 3*1 2, AA2 3*1 4. Due to the existence of 1 4AA, the proportion of AA in the inbred offspring of the first generation of AA after the elimination of AA is not a simple 2 3*2 3, so the calculation method of AA ratio is wrong.

You have to be clear that the total amount of producers is constant!

You can assume that the population in the first case is x, then from the title, x 2 is the energy provided by plants, and x 2 is the energy provided by herbivores, then the total number of producers = x 2 10% + x 2 (10%) squared.

In the second case, the number of people is y, and it can be seen that 4y 5 is the energy provided by plants, and y 5 is the energy provided by herbivores, then the total amount of producers = 4y 5 10% + y 5 (10%) squared.

Above: x2 10% + x2 (10%) squared = 4y 5 10% + y 5 (10%) squared.

Convert to x y=, a student just asked this question in the evening!

Select D, the protein contains n10 cavities, and each amino acid contains n after hydrolysis is 1, then it should be 10 peptides.

b. Each amino acid corresponds to not only one kind of transport RNA, and the same amino acid may have several codons, and there are also several kinds of transport RNA

c. The question should be wrong, the first ammonia base is not C2H5O4N but C2H5O2N. Glycine source burns C2H5NO2, alanine C3H7NO2, phenylalanine C9H11NO2, glutamic acid C5H9NO4. In this case, you first look at the polypeptide molecular formula There are 10 nitrogen, and each amino acid has only 1 nitrogen, which means that there are 10 amino acids that make up this peptide chain, so 9 water is removed when the peptide chain is formed, so the molecular formula can be written as C55 H88 O28 N1O before Wu Cracking, and then find the rule, glycine 2 oxygen, alanine 2 oxygen, phenylalanine 2 oxygen, and glutamic acid 4 oxygen

Let's assume that they all have 2 oxygen atoms and 10 amino acids, then there should be 20 oxygen atoms, and the real record has 28 oxygen atoms, which is 8 more, so those eight are glutamate because each glutamate has two more oxygen atoms than the others,。。 It is 4 glutamic acid and 8 more. --There are 4 participating peptides and glutamic acid molecules!!

d. If 9 water is removed, it will be reduced by 18*9=162

2.Then the tripeptide species they can form are a nine, and there are three of them, which is 27.

a b cabc abc abc

The three types of tripeptides containing three amino acids are up to six types: ABC, ACB, BAC, BCA, CAB, CBA.

1) The protein contains n10, and each amino acid contains n 1 after hydrolysis, so it should be 10 peptides.

Item B is not necessarily, each amino acid does not know a corresponding to a transport RNA, I don't know if you have learned this.

In item C, you first need to know which is glutamic acid C5H9O4N, and then set the number of various amino acids as A, B, C, D, and the carbon content is 2A+3B+5C+9D, and then list the other content of the formula A total of four can be listed, but pay attention to take off 9 molecules of water, and then calculate it should not be right, because I think the D term is right.

2) The words of tripeptide means that it can be repeated and merged, and it can also be used with grinding banquets Then there are three options for each of the three positions, so the type is 3*3*3=27Then the tripeptide containing three amino acids means that all three amino acids must be used, so the first one can have 3 kinds, the second position can only have two options, and the last one can only be the rest, the result is 3*2*1=6You'll learn this calculation in math, and now, you can write out the numbers, it's just troublesome.

Protein: 1. If the protein is a chain, there are: peptide bond number = amino acid number -1;

2. If the protein is composed of multiple chains, there are: number of peptide bonds = number of amino acids - number of peptide chains;

3. Number of peptide bonds = number of water molecules lost;

4. The relative molecular weight of the protein = the total mass of amino acids (the number of amino acids is flat.

Mean molecular weight) - water loss (water molecule number 18);

5. Ammonia number (carboxyl number) = number of peptide chains + R base number containing amino group (carboxyl group);

6. The number of bases of the gene: the number of messenger RNA bases: the number of amino acids = 6:3:1.

It's 1 6

Let's look at the man first: his mother has a single eyelid AA, whether the father is AA or AA, his genotype must be AA.

Woman: She has a younger brother who has AA parents, both of whom have double eyelids, so her parents are genotype AA. For women's double eyelids, genotype: 1 3AA or 2 3AA.

To give birth to a child with a single eyelid, aa aa, the probability of getting aa is 1 4. But the woman only has a chance of 2 3 being AA, so she has to multiply it by 2 3.

In this way, you should understand that assuming a=1, then B amino acids form a peptide chain and remove b-1 water, and a peptide chain removes b-a water, and the relative molecular mass of water required for hydrolysis is 18(b-a). The average relative molecular weight of amino acids is c, then the total molecular weight of all amino acids when they are not peptide chains is BC, then the water condensed when subtracting the peptide chains is the molecular weight of the protein = BC-18 (B-A) = BC-18B + 18A = B (C-18) + 18A