Hello fellow veterans, I believe many people do not know much about homologous chromosomes. Therefore, today I will share with you about homologous chromosomes and homologous chromosomes. What kind of knowledge does it refer to? I hope it can help everyone and solve some of your confusions. Let’s take a look together!
Contents of this article
- Proposal of the definition of homologous chromosomes
- The concept of homologous chromosomes
- The difference between synapsis and homologous chromosomes >
- What are homologous chromosomes?
- What are the compulsory courses for high school biology students 2? Are homologous chromosomes
- Homologous chromosomes and gene encyclopedia
1. Proposal of the definition of homologous chromosomes
Homologous chromosomes have the shape and structure in diploid biological cells Basically the same chromosomes, and synapse with each other during the tetrad stage of the first division of meiosis (refer to meiosis) (if it is a triploid and other odd-ploid biological cells, disorder will occur during synapsis), and finally A pair of chromosomes that are separated into different reproductive cells (i.e. sperm, egg cells). One of the chromosomes in this pair comes from the mother and the other comes from the father.
2. The concept of homologous chromosomes
1. Homology Chromosomes (homologouschromosomes): Two chromosomes with the same length and centromere position seen during mitosis, or paired chromosomes seen during meiosis.
2. One homologous chromosome comes from the father and the other comes from the mother; their shape, size and structure are generally the same. Since the number of chromosomes in each organism is certain, the number of pairs of homologous chromosomes is also certain. For example, peas have 14 chromosomes and 7 pairs of homologous chromosomes.
3. Homologous chromosomes often contain different alleles, which are exchanged during meiosis and randomly assigned to different sex cells. , which is of great significance for genetic recombination.
4. In normal cells, if a pair of homologous chromosomes is expressed as consisting of two chromosomes A and B, it becomes the \”AA`\” group and the \”BB`\” group during meiosis. The two groups synapse to form a tetrad.
5. During mitosis, they become the \”AA`\” group and the \”BB`\” group, but the two groups do not synapse. , in the metaphase of mitosis, the centromeres of the chromosomes are neatly arranged on the equatorial plate. After the centromeres separate, the chromosomes are evenly distributed to the two daughter cells.
6. In the large cell. Most often, homologous pairing occurs in germ cells, but it also occurs in somatic cells. For example, human somatic cells have very tightly regulated homologous pairing (segregated into chromosomal territories that pair at specific genetic loci under the control of developmental signals). ). Homologous pairing is more frequent in other species (especially Drosophila)
7. High-throughput screens in the early 21st century elucidated homologous pairing in somatic cells. Various functions of source pairing
3. The difference between synapsis and homologous chromosomes
The difference between the two lies in the behavior of chromosomes. Homologous chromosomes refer to one pair from the mother and one from the father. A pair of chromosomes with the same shape and size. Synapsis is the phenomenon of pairing of homologous chromosomes. A phenomenon unique to meiosis
4. What does homologous chromosomes mean?
1. 1. Homologous chromosomes refer to a pair of chromosomes with the same shape, size and function.
2. On homologous chromosomes Genes at the same position that control the same traits are called alleles. One homologous chromosome comes from the father and one comes from the mother. During meiosis, the homologous chromosomes replicate to form four sister chromatids, also known as alleles. Tetrad. The act of homologous chromosomes coming together during meiosis is called synapsis. During synapsis, crossover between non-sister chromatids of homologous chromosomes can occur during cell division. In one meiosis, homologous chromosomes are divided into two daughter cells. In the second meiosis, the two sister chromatids separate to form four daughter cells. Each daughter cell is also a germ cell and contains the number of chromosomes. Reduced by half
5. Compulsory Course 2 for High School Biology What are Homologous Chromosomes
The two paired chromosomes on page 18 of the book are generally the same shape and size. One comes from the father and the other comes from the mother. They are called homologous chromosomes.
6. Homologous chromosomes and gene encyclopedia
Homologous chromosomes mainly refers to the appearance of two identical chromosomes in the middle phase of mitosis , one chromosome comes from the father and one chromosome comes from the mother. The shape, size and structure of the chromosomes are exactly the same. They associate with each other during the tetrad stage of the first division of meiosis and then separate into different germ cells.
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