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
The fusion of the male and the female gametes is called ______.
Draw a labelled diagram of sperm.
The glandular accessory organ which produces the largest proportion of semen is ____________.
Give a schematic representation of spermatogenesis and oogenesis in humans.
During spermatogenesis, spermatogonium grows in size to become ______.
Which of the following correctly describes the secondary oocyte?
Calculate the number of sperms and ova produced from 40 primary spermatocytes and 40 primary oocytes.
Identify the longest period of menstrual cycle.
How many autosomes does a human primary spermatocyte have?
The principal tail piece of human sperm shows the microtubular arrangement of ______.
Layers of an ovum from outside to inside is ______.
Head of epididymis is called as ______.
Aquatic animals in which fertilisation occurs in water are said to be
Observe the given figure and answer the questions that follow.
- Label A and B.
- Identify the process.
- What happens during this process and what is formed?
In the process of fertilization, this is true:
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:
In human females, meiosis II is not completed until:
Given below are two statements.
- Statement I: The spermatids are non-motile and non-functional which get transformed into functional spermatozoa by the process of spermiogenesis.
- Statement II: During the process of this change, the spermatids remain held to each other and to Leydig's cells by cytoplasmic bridges.
In light of the above statements, select the correct answer from the option given below.
At the onset of puberty, gonadotropin releasing hormone is secreted by ______.
