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प्रश्न
What would be the effect if meiosis did not occur in nature?
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उत्तर
- During meiosis, reduction division produces four haploid cells (gametes i.e. human sperm cell and egg cell) from a single diploid cell. Hence, if meiosis does not occur, it will result in a doubling of chromosomes in each successive generation, which will result in the formation of abnormalities.
- If meiosis does not occur, the chromosome number of parents and their offsprings will differ in every generation, hence no species will hold its characters.
- Also, there will be no crossing over of homologous chromosomes. Thus, there will be no variations with respect to the changing environment in progeny to maintain their existence, which may lead to the extinction of species.
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संबंधित प्रश्न
Name the following:
The part where the sperms are produced in the testes
Choose the odd one in each of the following:
Sperm; implantation; fertilization; ovum; afterbirth
Choose the correct answer:
Virgin birth is called ______________
The diagram given below is that of a developing human foetus in the womb. Study the same and answer the question that follow:
Mention two functions of the parts labelled '2' other than its endocrine functions.
Give Reasons
A large number of sperms are required for fertilizing one egg.
Differentiate
External fertilization and Internal fertilization.
Complete the following sentences with appropriate word:
One egg is normally released from the ovary in the human females after
__________
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Sperm is a single cell.
Answer the following question.
What is capacitation? Give its importance.
What is fertilization?
Fertilization of the ovum generally takes place in the ______.
In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is
The eggs of frogs do not have shells for protection, yet they are safe in water, how?
Match the pair:
| 'A' | 'B' | ||
| (1) | Male | (a) | 44 + XX |
| (b) | 44 + XY | ||
| (c) | 44 + YY |
Choose the odd one out from the group of terms given below and write the category for the remaining terms:
Which enzyme dissolves the hyaluronic acid between corona radiata cells and the zona pellucida?
Which enzyme digests a localized hole in the zona pellucida to allow sperm entry?
What are the two sequential blocks that prevent polyspermy?
Which structure sweeps the ovum into the fallopian tube after ovulation?
What structures surround the ovum and aid in its protection and fertilization?
