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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
Define the Zygote.
When pregnancy does not occur, the life of corpus luteum is about ______.
Suppose a normal woman has never borne a child; How many mature eggs would she have produced in her lifetime? Your calculation should be based on two clues-
(a) Eggs are produced at the rate of 1 egg every 28 days (one menstrual cycle)
(b) A woman’s total reproductive period is 13 – 45 years.
Choose the odd one in each of the following:
Sperm; implantation; fertilization; ovum; afterbirth
What happens to uterus if fertilization takes place? And what happens to uterus if fertilization does not take place?
Give the functions of the following:
Fallopian tube
The diagram given below is that of a developing human foetus in the womb. Study the same and answer the question that follow:
How many days does the foetus take to be fully developed?
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.
What is fertilization? Name the site of fertilization in the human females.
How is the fetus protected?
Give Reasons
The oviduct funnel is lined with cilia.
Differentiate
Isogametes and Heterogametes.
Complete the following sentences with appropriate word:
Fertilization of the human egg by the sperm normally occurs in the_______
Multiple Choice Question:
Ovulation in mammals is a process in which
Write a short note on fallopian tube.
Give scientific reason.
The new individual produced by sexual reproduction always has the recombined genes of both the parents.
State whether True or False:
The chromosome number in germ cells producing the gametes are diploid.
Give any four significances of fertilization in humans.
Name the parts of fallopian tubes.
Match the pair:
| 'A' | 'B' | ||
| (1) | Male | (a) | 44 + XX |
| (b) | 44 + XY | ||
| (c) | 44 + YY |
