The normal number of chromosomes in the progeny is maintained when the...
The number of chromosomes in each generation are maintained due to meiosis. The meiosis is a kind of reductive division. When gametes are formed by meiosis, the number of chromosomes are halved. Hence each gamete will have only one pair of chromosome.
Later the haploid gamete will fuse with the complementary haploid gamete and form Diploid Zygote(2n). Hence the number of chromosomes are maintained.
For more details you can view my old answers regarding S-phase, certain stages of meiosis etc. If still you have doubts, you can ask anytime or you can refer Molecular cell biology by Bruce Alberts.
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The normal number of chromosomes in the progeny is maintained when the...
Explanation:
The normal number of chromosomes in the progeny is maintained when the germ cells take one chromosome from each pair.
Chromosomes and Germ Cells:
- Chromosomes are thread-like structures located inside the nucleus of a cell. They carry genetic information in the form of genes.
- Germ cells are specialized cells that give rise to gametes (sperm and eggs) through a process called gametogenesis.
Chromosome Number in Progeny:
- The chromosome number in an organism is referred to as its ploidy level. In humans, the normal ploidy level is diploid, which means having two sets of chromosomes.
- During sexual reproduction, two gametes (one from each parent) combine to form a zygote. The zygote then undergoes cell division to develop into an organism.
- To maintain the normal chromosome number in the progeny, the germ cells must contribute only one chromosome from each pair.
Process of Meiosis:
- Germ cells undergo a specialized form of cell division called meiosis to produce gametes.
- Meiosis consists of two rounds of division (meiosis I and meiosis II) and results in the formation of four haploid cells (gametes) from a diploid cell.
- During meiosis I, homologous chromosomes pair up and exchange genetic material through a process called recombination or crossing over.
- In meiosis II, sister chromatids of each chromosome separate, resulting in the formation of four genetically distinct haploid cells.
Chromosome Segregation in Meiosis:
- During meiosis I, when homologous chromosomes pair up, they align at the center of the cell in a process called metaphase I.
- The homologous chromosomes then separate, with one chromosome from each pair moving to opposite poles of the cell during anaphase I.
- This random separation of homologous chromosomes ensures that each resulting gamete receives one chromosome from each pair, contributing to the maintenance of the normal chromosome number in the progeny.
Conclusion:
The correct answer is option 'D' - When germ cells take one chromosome from each pair. This process occurs during meiosis, where homologous chromosomes separate, resulting in haploid gametes with the normal number of chromosomes.
The normal number of chromosomes in the progeny is maintained when the...
No correct answer is b
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