Advertisements
Advertisements
प्रश्न
Give scientific reason.
Older women are more likely to give birth to children with some abnormalities.
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
Draw a diagram of the microscopic structure of human sperm. Label the following parts in it and write their functions:
- Acrosome
- Nucleus
- Middle piece
Ovulation is induced by a hormone called ______.
Define spermiation.
Describe the process of budding in hydra.
What is gamete formation?
Mammalian egg is ____________.
Mention the differences between spermiogenesis and spermatogenesis.
At what stage of development are the gametes formed in newborn male and female?
Select the correct sequence of oogenesis.
Which of the following is diploid?
Draw a labelled diagram of a Graafian Follicle.
How many sperms are formed from a secondary spermatocyte?
Sertoli cells are found in ______.
Which of the following stage of oogenesis forms a membrane called zona pellucida surrounding it?
Which of the following contains a fluid filled cavity called antrum?
Cells of corona radiata remain grouped together by ______.
Gray crescent is the area ______.
During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring. What are the processes through which these events take place?
How many spermatozoa are formed from one secondary spermatocyte?
In spermatogenesis, at the end of the first meiotic division ______ are formed.
