Biology master about zygotes .

1.Self-crossing (crossing with an individual of the same genotype) is heterozygous if there is trait separation, otherwise it is homozygous.

2.Hybridization (hybridization with recessive homozygotes) is homozygous if the offspring are all dominant, and heterozygous if the ratio of the offspring is 1:1.

1.Inbred – if the offspring has recessive traits, it is heterozygous. Otherwise homozygous.

2.If the ratio of progeny trait segregation is 1:1, it is heterozygous, and if there is no trait segregation, it is homozygous.

Self-breeding, if there is trait separation, it is heterozygous.

Measurement or self-crossing (plants).

In addition to the above, for specific plants, it can also be determined by the method of flower grain dyeing, but it is more troublesome. Or take its pollen, carry out anther in vitro culture, observe the traits of offspring, and if there is no trait separation, it is homozygous.

1. Mu has learned...

2. T is the phagocytic cell that transmits B seems to be able to recognize a part of it and then differentiate.

3. Except for plasma cells, everything else is fine. It relies on the epitope on the surface of the antigen, which is a protein.

4. Within the target cell.

5. Macrophages recognize antigens and pass signals to T, which differentiates and destroys target cells. Macrophages. I think it depends on whether the antigen is released into the internal environment or whether it secretes harmful substances, and if so, T and B and other immune cells are involved.

This question is in the book.

21. Establish a plane Cartesian coordinate system, the horizontal axis can be time, the vertical axis can be the concentration of CO2 and the like, and then control the variables other than temperature, so that it is the influence of temperature, if you do not control the light, constant temperature, it is light, and so on.

2. Think about what will be directly affected if the environment changes, and then what will be affected next.

3. This has to be seen first to see whether it is net photosynthesis or total photosynthesis, net photosynthetic rate = real photosynthetic rate - respiration rate.

4. This... I vaguely remember that the teacher seemed to be talking about moving the coordinate axis... I don't remember...

5. Are you talking about the biological chain or the ecosystem? Let's talk about this private message.

6. If there is data, the safest way is to draw a table and trace the point, of course, I generally write the S type directly when I do the question, because if it is analyzed, it is not an ideal situation. . . Of course, not counting the type of biological invasion, what Australian rabbits.

Uh,That,Maybe some of it is wrong or I don't understand what you mean.,I think it's rare for some to ask.。。。

Organisms can be divided into single-celled organisms and multicellular organisms according to the number of cells they are composed ofSingle-celled organisms are composed of only a single cell, the individual is tiny, and it is difficult to see with the naked eye, most single-celled organisms live in a water environment, and some parasitize us.

Give me some points.

Single-celled plants: including single-celled algae (such as diatoms, Chlamydomonas) and other single-celled animals: paramecium, malaria parasites, etc.

Single-celled fungi: yeasts, etc.

Prokaryotes: including cyanobacteria and bacteria (e.g., Escherichia coli, staphylococcus) Seedless single-celled organisms: various viruses (SARS virus, HTV virus) Single-celled organisms are organisms composed of only a single cell, and often aggregate into cell colonies.

Although single-celled organisms are composed of only one cell, they can also complete life activities such as nutrition, respiration, excretion, movement, reproduction, and regulation. is the simplest form of life. There are mainly nucleated and non-nucleated single-celled organisms.

The common characteristics of unicellular organisms are:

1.Unicellular animals and plants are the lowest.

2.The structure is the simplest.

3.The individual is tiny, and all life activities are completed in a single cell.

4.Generally lives in water.

Single-celled organisms appeared 3.5 billion years ago.

Each monomer is composed of only one cell and has the functions of completing metabolism and genetics.

As a living organism, a single-celled organism is the simplest, but as a cell, a single-celled organism is the most complex.

Closed-flower pollination is equivalent to isolating from external interference, which you already know. If the plant is homozygous for AA, then it will only get the A gene from closed pollination, which will not be disturbed by pollen from the outside world (assuming the wind blows from the adjacent plant). The resulting plant must be genotype AA

In layman's terms, if you imagine a cluster of flowers, and the AA plants that you are interested in, there must be AA and other other genotypes around you, and their pollen is scattered in the air by the wind, and if the AA plant is not pollinated with closed flowers, how can you ensure that the pollen with the A gene does not interfere with its pollination process?

I don't know what high school biology looks like, but the objective fact is this: DNA transcription is a very complex process, and until now all the functions of each subunit of RNA polymerase holoenzyme have not been fully understood, and there are countless types of transcriptase in various organisms alone. But transcription definitely requires unwinding, and it is done by a subunit of the holoenzyme, such as the E. coli RNA polymerase factor, which is responsible for unwinding and re-double-stranding.

Our teacher said that this does not need to be mastered.

In fact, what you have to ask is how to break the hydrogen bonds of DNA transcription?

After the RNA polymerase binds to the promoter, it breaks the hydrogen bond between the two strands of the DNA double helix in a specific region, allowing the DNA to unwind, forming a single-stranded region

Of course, there's DNA polymerase.

The double-strands are unwound by DNA helicase and then base paired by RNA polymerase, etc.

Of course, in the end, the double strands are reduced by an enzyme, and I don't know what this is.

Helicase is required because the hydrogen bond is to be opened.

The high school problem should be the default ideal conditions, and the real situation should be that with the increase of the number of self-confessors, the proportion of homozygotes in the offspring is increasing, and the proportion of heterozygotes is already very small.

If the original organism is heterozygous, then with each closed pollination, the plant will always have trait separation after self-breeding, and with the increase of self-metasody, even if it is originally a heterozygous, it will eventually become homozygous as the self-breeding progresses.

Infertility means that it is impossible to produce the next generation through sexual reproduction, and of course it is not heritable. Because heredity occurs during reproduction.

Mules are sterile, do you say their traits are heritable?

The seeds in seedless watermelons are the seeds of triploid watermelons formed by hybridizing natural diploid watermelons with tetraploids that have undergone mutagenesis. Because it is triploid and has to be treated with colchicine, it has no reproductive ability and no seeds. Common watermelon is a diploid plant, that is, there are 2 sets of chromosomes (2n 22) in the body, and its seedlings are treated with colchicine, so that the chromosomes of the diploid watermelon plant cells become tetraploid (4n 44), this tetraploid watermelon can flower and bear fruit normally, and the seeds can germinate and grow normally.

The cultivation of seedless watermelon is to breed triploid plants, so that they will be disordered, so that watermelon seeds cannot be produced. The method is to treat diploid seedlings with colchicum to produce quadruploid plants, which are chromosomal changes, and then use diploid and tetraploid hybridization to produce triploid watermelon seeds. Because the seeds are triploid, many fruits are produced by artificial pollination as seedless watermelons.

So the cultivation principle of seedless watermelon is chromosomal aberration.

Ultimately, the conclusion is that this trait is not heritable and triploidy is not heritable, just like mules.

Seedless watermelons are generally triploid and cannot form gametes normally, so they cannot produce offspring. The parents of all seedless watermelons are fertile, such as triploid watermelons are crossed from diploid and tetraploid watermelons. Therefore, there is no question ......of inheritance or non-inheritance of childless traits, and there is no way to produce gametes at allare all extinct ......

- -Unless you use tissue culture, how do you let other 3n gametes be distributed, and you decide to fight wow!

Non-heritable, seedless watermelons are newly cultivated every year.