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
How is 'oogenesis' markedly different from 'spermatogenesis' with respect to the growth till puberty in the humans?
Male and female gametes are ______.
Ovulation is induced by a hormone called ______.
In angiosperms, the pollen germinates to produce a pollen tube that carries two gametes. What is the purpose of carrying two gametes when a single gamete can fertilize the egg?
The following is the illustration of the sequence of ovarian events (a-i) in a human female.
Identify the figure that illustrates ovulation and mention the stage of oogenesis it represents.
500 spermatozoa are formed from ____________ secondary spermatocytes.
______ undergoes 2nd meiotic division during spermatogenesis.
The human male gamete is usually about ______ in length.
After ovulation, Graafian follicle regresses into ______.
Which of the following contains a fluid filled cavity called antrum?
There is no cell division involved in ______.
During embryonic development, the establishment of polarity along anterior/posterior, dorsal/ventral or medial/lateral axis is called ______.
A reaction of granules content which harden the zona pellucida and ensures sure block to polyspermy is ______.
Which of the following groups of cells in the male gonad, represent haploid cells?
After the release of the secondary oocyte, the Graafian follicle develops into ______.
If for a species 2n = 16, then during Ist prophase and IInd prophase of the meiotic division of a cell, how many tetrads and diads will be formed:
Human milk differs from cow's milk because human milk contains:
Capacitation refers to changes in the ______.
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?
In our society the women are often blamed for giving birth to daughters. Can you explain why this is not correct?
