At least one chromosome in a female cell comes from a grandmother Why is it wrong?!

Female X chromosome cells, one X from the father and one X from the mother, and the father's sex cells, X must be from the grandmother and Y must be from the grandfather, so I think "at least one chromosome in the female cell is from the grandmother", it should be right.

If it is said that "at least one chromosome in a woman's cell comes from her maternal grandmother", then this is not necessarily the case. Because the mother's X chromosome, one from the maternal grandfather and one from the maternal grandmother, the X chromosome passed on to the next generation may come from the maternal grandfather or maternal grandmother.

This sentence is true, the chromosomes of a woman are type XX, one from the father and one from the mother, and the one from the father must be provided by the grandmother, because the father is type XY, the Y chromosome can only be provided by the grandfather, and the X chromosome is provided by the grandmother, so under normal circumstances, the female must have a chromosome from the grandmother. There are also special cases, provided that the female has three sex chromosomes, and xxy also behaves as female, but dies shortly after birth. If that's a tricky question.

It may be that the chromosomes have changed during the crossover, so it is not necessarily.

The third floor confuses grandmother with maternal grandmother, grandmother is the father's mother, not the mother's mother.

Because. The sex chromosomes of females are xxOne of them is from the father and one is from the mother. And the mother's two xx are from the maternal grandmother or maternal grandfather. So one of them must be from my grandmother.

Not necessarily. If it is a sex chromosome: grandmother x1x1, grandfather x2y2, mother x1x2 - father x3y3, born daughter may be x1x3 or x2x3. So it is possible that the chromosomes of the female cells are not from the grandmother.

If it's autosome, it's possible.

Chromosomes exist in pairs in somatic cells; Different organisms have completely different morphologies and numbers of chromosomes;

In the same organism, the chromosomes maintain a certain morphology and number; For example, the somatic cells of normal people contain 23 pairs of chromosomes, and the chromosomes of rice are 12 pairs, so there are many somatic cells in multicellular organisms, and the number of chromosomes in somatic cells is the same, so this statement is correct

So the answer is:

Test Center: Human Sex Inheritance Special Topic: Analysis:

There are 23 pairs of chromosomes in both male and female somatic cells, and there are 22 pairs of chromosomes whose morphology, size and size are basically the same for men and women, which are called autosomes; There are obvious differences in the morphology and size of the 23rd pair of chromosomes, which are related to the sex determination of people, called sex chromosomes The sex chromosomes in female somatic cells are basically the same in size, called xx chromosomes, and among the sex chromosomes of male somatic cells, one of the larger trousers is named the X chromosome, and the smaller one is called the Y chromosome The process of human sex inheritance is shown in the figure: From the sex inheritance**, it can be seen that the composition of chromosomes in the somatic cells of the girl is 44+xx Therefore, it is selected :d Comments:

The key to answering such questions is to answer them with the help of sex genetic analysis

c, chromosomes are basically paired, one chromosome has only one of the paired genes, and the other is on the other.

Answer B The number of chromosomes in the primary oocyte is the same as that of the somatic cell, the DNA is twice that of the somatic cell, the egg cell is the germ cell, the number of chromosomes is half of the somatic cell, the number of chromosomes in the secondary spermatocyte is half of the somatic cell or the same as the somatic cell, the DNA is the same as the somatic cell, the number of chromosomes in the spermatocyte is half of the somatic cell macroprotour, and the DNA is half of the somatic cell. The chromosomes of the oocyte and the DNA are the same as the syncylocytes, and the number of chromosomes in the body is half that of somatic cells, so option B is correct.