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प्रश्न
Give scientific reason.
Older women are more likely to give birth to children with some abnormalities.
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उत्तर
- A female has millions of oocytes at the time of birth and new ova are not formed thereafter.
- Menopause occurs at approximately 40-50 years of age and hence fewer numbers of eggs are present with reduced fertility since the oocytes have aged.
- Their ability to divide diminishes and they may not be able to complete meiotic division properly.
- Fertilization of such oocytes may result in the production of genetic abnormalities (like Down syndrome) in offspring.
Hence, older women are more likely to give birth to children with some abnormalities.
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संबंधित प्रश्न
Draw a sectional view of human ovary and label the different follicular stages, ovum and Corpus luteum.
Draw a diagram of the microscopic structure of human sperm. Label the following parts in it and write their functions:
- Acrosome
- Nucleus
- Middle piece
In meiosis, the number of chromosomes becomes ___________.
What is gamete formation?
Mention the differences between spermiogenesis and spermatogenesis.
Give a schematic representation of spermatogenesis and oogenesis in humans.
Identify the given image and label its parts marked as a, b, c and d
Identify the labels (i-iv) in the given diagram of the ovum.
Select the correct sequence of oogenesis.
Identify the CORRECT sequence of events.
Which of the following events take place during spermatogenesis?
Extrusion of second polar body from egg nucleus occurs ______.
Which of the following stage of oogenesis forms a membrane called zona pellucida surrounding it?
The nutritive cells found in seminiferous tubules are ______.
The process of release of spermatozoa from Sertoli cells into cavity of the seminiferous tubules is called ______.
Mark the odd one.
Follicular atresia is:
Human milk differs from cow's milk because human milk contains:
Draw a labelled diagram of a section through the ovary.
The process of gametogenesis is initiated by ______ and ______ hormones respectively.
