Question

explain sexual reproduction in human beings ( 60-80 words )

Answer 1

Answer:

Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete (such as a sperm or egg cell) with a single set of chromosomes (haploid) combines with another to produce a zygote that develops into an organism composed of cells with two sets of chromosomes (diploid).[1] Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction does not occur in prokaryotes (organisms without cell nuclei), but they have processes with similar effects such as bacterial conjugation, transformation and transduction, which may have been precursors to sexual reproduction in early eukaryotes.

In the first stage of sexual reproduction, "meiosis", the number of chromosomes is reduced from a diploid number (2n) to a haploid number (n). During "fertilisation", haploid gametes come together to form a diploid zygote, and the original number of chromosomes is restored.

In the production of sex cells in eukaryotes, diploid mother cells divide to produce haploid cells known as gametes in a process called meiosis that involves genetic recombination. The homologous chromosomes pair up so that their DNA sequences are aligned with each other, and this is followed by exchange of genetic information between them. Two rounds of cell division then produce four haploid gametes, each with half the number of chromosomes from each parent cell, but with the genetic information in the parental chromosomes recombined. Two haploid gametes combine into one diploid cell known as a zygote in a process called fertilisation. The zygote incorporates genetic material from both gametes. Multiple cell divisions, without change of the number of chromosomes, then form a multicellular diploid phase or generation.

In human reproduction, each cell contains 46 chromosomes in 23 pairs. Meiosis in the parents' gonads produces gametes that each contain only 23 chromosomes that are genetic recombinants of the DNA sequences contained in the parental chromosomes. When the nuclei of the gametes come together to form a fertilized egg or zygote, each cell of the resulting child will have 23 chromosomes from each parent, or 46 in total

Answer 2

Answer:

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Reproduction in human beings is by sexual reproduction where both the male and female gametes fertilize to give rise to an embryo. The fertilization of human embryo occurs inside the body of the female. Thus, it is called Internal Fertilization. Human Beings are viviparous organisms who give rise to Embryos directly instead of laying eggs. Let us understand a little more about the male and female reproductive organs and the process of fertilization in them.