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प्रश्न
Do all the gametes formed from a parent organism have the same genetic composition (identical DNA copies of the parental genome)? Analyse the situation with the background of gametogenesis and provide or give suitable explanation.
उत्तर
The gametes of a parent do not have the same genetic composition because they do not have identical copies of DNA. In the pachytene and diplotene stages of meiosis I, the phenomenon of crossing over and chiasma formation take place between homologous chromosomes. This shifts segments of DNA from one chromatid to another (homologous chromosomes) in a random manner resulting in several new combinations of DNA sequences. As a result, when meiotic division is completed, gametes possess DNA with varying degree of variations.
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संबंधित प्रश्न
Explain the significance of meiocytes in a diploid organism.
Differentiate between gametogenesis from embryogenesis.
Examine a few flowers of any cucurbit plant and try to identify the staminate and pistillate flowers. Do you know any other plant that bears unisexual flowers?
External fertilisation occurs in majority of ______.
Choose the statements that are true from the options below:
The statements given below describe certain features that are observed in the pistil of flowers.
- Pistil may have many carpels
- Each carpel may have more than one ovule
- Each carpel has only one ovule
- Pistil have only one carpel
In flowering plants both male and female gametes are non-motile. The method to bring them together for fertilization is ______.
Why is vivipary an undesirable character for annual crop plants?
In meiosis, division is ______.
Is the presence of large number of chromosomes in an organism a hindrance to sexual reproduction? Justify your answer by giving suitable reasons.
In haploid organisms that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs. Give reasons for your answer.
