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प्रश्न
Give a reason for the following:
Gametes must be produced by meiosis for sexual reproduction.
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उत्तर
Meiosis is a type of cell division that reduces the chromosome number by half, necessitating the production of gametes for sexual reproduction. Gametes are haploid cells, which means that they contain half the number of chromosomes present in diploid cells (such as somatic cells). During fertilisation, the resulting zygote has the full diploid chromosome number when two gametes (sperm and egg) with half the chromosome number each fuse. Variation in the population is a result of the genetic diversity that is necessary for progeny to inherit a distinctive combination of genetic material from both parents.
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संबंधित प्रश्न
Correct the following statement if there is any mistake:
If there are 46 chromosomes in a cell, there will be 23 chromatin fibres inside the nucleus during interphase.
Choose the correct answer:
Chromosomes number is halved in _____________
Choose the correct answer:
During mitosis which of the following disintegrate ___________
Mention the contribution of the scientist given below in the study of chromosome:
Strasburger
Choose the correct answer:
Telocentric chromosomes are _________________
What are chromosomes?
Enumerate the various changes that occur in the nucleus of the cell during prophase.
Enumerate the various changes that occur in the nucleus of the cell during anaphase of mitotic division.
State how does meiosis maintains chromosome number in a species.
What is the importance of meiosis?
(i) Draw a neat labeled diagram to show the metaphase stage of mitosis in an animal cell having ‘6’ chromosome.
(ii) How many daughter cells are formed at the end of mitosis and at the end of meiosis?
(iii) With reference to cell division explain the following terms:
(Chromatid, Centromere, Haploid).
(iv) Name the type of cell division that occurs during:
1. Growth of shoot 2. Formation of pollen grains.
3. Repair of worn out tissues.
Explain the Term Zygotene
Write the functional activity of the following structure:
Chromosome
Name the following:
Pairs of chromosomes, present in human egg cells.
Complete the following sentence with appropriate word:
The number of chromosomes in humans is ________.
What is allosome?
Define euploidy.
Give the example of X- monosomy you have studied.
Read the following statements and select the correct option.
Statement I: The densely packed transcriptionally active, light staining region of chromatin is known as 'Heterochromatin'.
Statement II: The loosely packed, dark staining transcriptionally inactive region of chromatin is known as 'Euchromatin'.
