Meiosis Question And Answers

Question 1. Meiosis
Answer:

• Meiosis is cell division which reduces the number of chromosomes to half.
• It occurs in all sexually reproducing single celled and multicellular eukaryotes.
• In meiosis, DNA replication is followed by two rounds of cell division to produce four potential daughter cells
• Before meiosis begins, during S phase of the cell cycle, DNA of each chromosome is replicated so that it consists of two identical sister chromatids

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Meiosis Phases:

• Meiosis is divided into meiosis I and meiosis II
  1. Meiosis I
     • Meiosis I seggregates homologous chromosomes which are joined by tetrads
     • It produces two haploid cells
       1. Prophase I
          • It is longest phase of meiosis
          • In it homologous chromosomes pair and exchange DNA called homologous recombination
          • It is divided into series of substages like
            • Leptotene
            • Zygotene
            • Pachytene
            • Diplotene
            • Diakinesis
  2. Metaphase I
     • In this stage, the paired homologous chromosomes align along the equatorial plane
  3. Anaphase I
     • Pulling of homologous chromosomes to opposite poles occurs
  4. Telophase I
     • It is last stage of meiosis I
     • It ends when the chromosomes arrive at the poles
     • Each daughter cell now has half the number of chromosomes and each chromosomes consists of a pair of chromatids
  5. Meiosis II
     • It involves separation of sister chromatids
     • It results in production of four haploid cells from two haploid cells.

Question 2. Gene.
Answer:

• It is a segment of DNA which contains the information (code) for the synthesis of one complete polypeptide chain (or an enzyme).
• It is a set of instructions for making proteins.
• Genes control the development of functioning of cells.
• They play an important role in the development of tissues and organ of an individual.