Spatial relationship of the chromosome group to the chromosome group

There is no boundary between the chromosome set inside the nucleus and another chromosome group, but it is artificially prescribed that those non-homologous chromosomes form a chromosome group, which carries the full set of genetic information of the organism, as long as it is composed of non-homologous chromosomes, and does not stipulate which of the homologous chromosomes belongs to which chromosome group. Their spatial location is not independent.

There are no boundaries. Groups are artificially divided.

The concept is that a group of non-homologous chromosomes in a cell, which are different in morphology and function, but carry all the information that controls the growth, development, heredity and variation of an organism, such a set of chromosomes is called a chromosome set.

There is no spatial boundary, it is just an academic classification, the function is the same, and the group that contains all the genetic information is called the chromosome, which is scattered in the nucleus

What is a chromosome group?

A group of non-homologous chromosomes in a cell, which are different in morphology and function, but carry all the information that controls the growth, development, heredity and variation of an organism, such a group of chromosomes is called a chromosome group.

For diploid organisms, the somatic cells of its haploid contain only one chromosome set, for example, corn is diploid, its somatic cells contain two chromosome sets and 20 chromosomes, and the somatic cells of its haploid plants contain 1 chromosome set and 10 chromosomes, but some haploid organisms contain more than one chromosome set in their somatic cells. For example, common wheat is hexaploid and has 6 chromosome sets and 42 chromosomes in its somatic cells, while its haploid plants have 3 chromosome sets and 21 chromosomes in their somatic cells.

What does the chromosome group mean.

Differing in size and morphology A set of chromosomes that contain all the genes of the organism.

What is a chromosome? What are alleles, non-alleles?

1.The chromosome group refers to the sum of chromosomes or genes contained in a gamete.

2.The somatic cells of most eukaryotes are diploid cells, and the chromosomes in the cells exist in pairs, and the two are homologous chromosomes to each other; There is only one chromosome of each type in a germ cell, so it is a haploid cell. Each gene in diploid cells is also found in pairs, and each pair of genes is located in the same position on the chromosome from both parents, and this location is called a locus.

A pair of genes on the same locus of a pair of homologous chromosomes is called a pair of alleles. For example, the tall stem gene of pea is an allele of the short stem gene of each other. A diploid organism is heterozygous for a pair of different alleles, and vice versa.

3.Non-allelic genes are genes located at different positions on homologous chromosomes or on non-homologous chromosomes, such as tall stem gene d and safflower gene c. This one is more complicated, see the encyclopedia, the link below.

The genome refers to a group of non-homologous chromosomes in a cell and is now widely used as a specialized term. Usually the number of chromosomes contained in various organisms is constant, such as rice has 24 chromosomes, while humans have 46 chromosomes, in the process of sexual reproduction, the number of chromosomes that normal gametes have is called the chromosome group, so that a set of chromosomes in rice and humans includes 12 pairs and 23 pairs respectively.

Number of chromosome groups judged by the group:

Judging several ploidies is actually judging the number of chromosomes in the somatic cells of a certain individual. Since there are no homologous chromosomes in a chromosome set, the number of homologous chromosomes becomes the main basis for judging the number of chromosomes, that is, judging how many ploids a certain body is. A and a, a and a are the same genes, listed on homologous chromosomes, and a and a, are alleles, also listed on homologous chromosomes.

There are several homologous chromosomes of the same letter (both upper and lowercase). Therefore, AA is a pair of homologous chromosomes with two sets of chromosomes, which is called diploid. AAAA is 4 homologous chromosomes with 4 chromosome sets, which is called tetraploidy.

AAABBBCCC is a group of 3 homologous chromosomes, containing 3 chromosome groups, called triploid.

AABBCCDD is a group of 2 chromosomes called diploidy. aaaabbbb contains 4 chromosome groups, and the fastest way to judge is to look at the number of homologous chromosomes (look at the bold letters).

If there are several chromosomes of the same morphology in a cell, there are several chromosome sets. There are several morphologies of chromosomes inside a cell, and there are several chromosomes within a chromosome set.

Chromosomes and chromosomes are different forms of the same substance at different times.

Chromosomes are the carriers of genes, and chromosomes include two parts: DNA and protein.

The proteins on the chromosomes of eukaryotic cells mainly include histones and non-histone proteins. Histones are a class of small, positively charged nuclear proteins that have a high affinity for DNA. Histones are the structural proteins of chromosomes that make up nucleosomes along with DNA.

Chromatin filaments made up of DNA and histones are rosary-like structures connected by many nucleosomes.

In terms of DNA, the most important feature of the eukaryotic cell genome is that it contains a large number of repeats, and the functional DNA sequences are mostly separated by non-functional DNA sequences that do not code for proteins.

At the end of the chromosome of eukaryotic cells there is a special structure called telomereTelomeres are a complex of DNA and proteins. The DNA sequence of telomeres is quite conserved, and its DNA is generally composed of multiple short oligonucleotide sequences linked together, each of which is 5 8 bp. in length

Telomeres can be expressed as follows:

5’-(txgy)n

3’-(axcy)n

Among them, x and y are the base numbers, which are generally 1 4The composition of base pairs varies from species to species, e.g. T2AG3 for humans and vertebrates, T4G4 for ciliated protozoa, T2G4 for Tetrahymena, and Yeast for short sequences, which can be in the thousands. The length of telomeres varies greatly in different organisms, with telomere DNA up to 150 kb (kilo base) in mice and about 5 15 kb in humans

The function of telomeres, like their sequences, is quite conserved. Telomeres have the following functions: (1) to ensure the complete desensitization and formation of linear DNA; (2) protect the ends of chromosomes; (3) Determine the lifespan of the cell.