Meiosis-Number of chromosomes

  • Thread starter omni
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In summary, the conversation discusses the doubling of DNA molecules and mass after DNA multiplication in a fertilized cell, specifically in reference to S-phase replication before mitosis. The individual is questioning if their understanding is correct, and confirmation is given by another participant.
  • #1
omni
192
1
In the picture you can see 2 table.
Table-1 is the original table that I got on my question,and table-2 is my answer.
I would like to know if I correct.



Thanks.
 

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  • #2
After DNA multiplication in a fertilized cell, the DNA molecules and mass will double...so 2m and 92.

This is referring to S-phase replication, before mitosis.

There might be something tricky about the number of DNA molecules, but I think what I said is correct.
 
  • #3
yep i think you are correct.

thank you :)
 
  • #4
yes you are right, as already stated the DNA molecules will double as well as mass.
 
  • #5


Meiosis is a type of cell division that results in the production of gametes, or reproductive cells. During meiosis, the number of chromosomes in a cell is reduced by half, resulting in the formation of haploid cells. This process is essential for sexual reproduction and ensures genetic diversity in offspring.

Table-1 shows the number of chromosomes present in each stage of meiosis in a diploid cell, which contains two sets of chromosomes. In prophase I, homologous chromosomes pair up and exchange genetic material through crossing over. This results in the formation of four chromatids, as shown in Table-1.

In metaphase I, the homologous chromosomes line up at the equator of the cell, and in anaphase I, they separate and move to opposite poles. This results in the formation of two haploid cells, each containing one set of chromosomes. The same process occurs in prophase II, metaphase II, and anaphase II, resulting in the formation of four haploid cells.

Table-2 shows the correct number of chromosomes in each stage of meiosis. Each haploid cell contains half the number of chromosomes as the original diploid cell. Therefore, in humans, where the diploid number is 46, the haploid number would be 23.

In conclusion, your answer in Table-2 is correct, showing the correct number of chromosomes in each stage of meiosis. It is important to understand the process of meiosis and the reduction of chromosomes to ensure the proper formation of gametes and genetic diversity in offspring.
 

1. What is the purpose of meiosis?

The purpose of meiosis is to produce genetically diverse reproductive cells, or gametes, for sexual reproduction. This process involves the division of a diploid cell into four haploid cells, each with half the number of chromosomes as the original cell.

2. How many chromosomes are present in a human cell after meiosis?

After meiosis, there are 23 chromosomes present in a human cell. This is because meiosis produces four haploid cells, each containing 23 chromosomes, which combine during fertilization to form a diploid zygote with 46 chromosomes.

3. Can the number of chromosomes vary in different species during meiosis?

Yes, the number of chromosomes can vary in different species during meiosis. For example, humans have 23 pairs of chromosomes, while fruit flies have only 4 pairs. This variation in chromosome number is due to differences in the genetic makeup and evolutionary history of different species.

4. How does meiosis ensure genetic diversity?

Meiosis ensures genetic diversity through several mechanisms. First, during the first division of meiosis, homologous chromosomes exchange genetic material through a process called crossing over, creating new combinations of genes. Additionally, during the second division, the chromosomes randomly line up and separate, further increasing genetic variation in the resulting gametes.

5. Can errors occur during meiosis that affect the number of chromosomes?

Yes, errors can occur during meiosis that can affect the number of chromosomes. This can result in aneuploidy, where there is an abnormal number of chromosomes in the resulting gametes. This can lead to genetic disorders, such as Down syndrome, in which there is an extra copy of chromosome 21.

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