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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.
Name the following:
The part where the sperms are produced in the testes
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.
The middle piece of sperm provides:
Differentiate between:
Semen and sperm
Define the following:
Spermatogenesis
Name two essential structures which take part in fertilization.
Give Reasons
Millions of sperms are produced at ejaculation yet one sperm actually fertilizes the ovum. Explain.
Give Reasons
A large number of sperms are required for fertilizing one egg.
Study the diagram given below and then answer the questions that follow:
(i) Name the part labeled A. Name any two hormones produced by the part labeled A.
(ii) What happens to the part labeled B.
(1) if fertilization takes place?
(2) If fertilization does not take place?
(iii) Where does fertilization occur?
(iv) Draw a neat diagram of the human sperm as seen under high magnification and label the following parts.
(1) Acrosome
(2) Mitochondria
Explain the Term Vas deferens.
Give Technical Term:
How much semen is discharged per ejaculation in a man?
Give Technical Term:
The place where fertilization occurs in the female reproductive system.
Complete the following sentences with appropriate word:
The process of releasing an egg from the ovary is called _________.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Fertilization is the product of the egg nucleus and the sperm nucleus.
Write the functional activity of the following structure:
Prostate gland
Which parts are converted into Seed and fruit respectively after fertilization?
Identify the function of fertilization membrane.
In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is
State whether the following statement is True or False. If false, correct the statement:
External fertilisation can occur both in water and on land.
