3. Give reason :
(a) Gametes must be produced by meiosis for sexual
reproduction.
(b) Why is meiosis referred to as 'reductional division ?
(c) The children of the same parents, howsoeve
4. Distinguish between the following pairs :
(a) Cytokinesis and Karyokinesis
(b) DNA and RNA
(C) Nucleosome and Nucleotide
(d) Centrosome and Centromere
(e) Haploid and Diploid
Answers
Answer:
1) Gametes must be produced by meiosis for sexual reproduction because the numbers of chromosomes are reduced to half during meiosis and then the normal diploid numbers of chromosomes are regained during the process of fertilization.
Explanation:
2) The process of meiosis involves two divisions of the genetic material. The first division is called the reduction division – or meiosis I – because it reduces the number of chromosomes from 46 chromosomes or 2n to 23 chromosomes or n (n describes a single chromosome set).
3) Parents don't pass genes to their offspring, they pass chromosomes. Every cell in a father contains a set of genes that are exactly alike. The same thing is true with every mother. In fact, they got these genes from their own parents (through their chromosomes)
answer 4
1) Karyokinesis is the process of division of the nucleus of a cell during the phase of division (mitosis or meiosis). Cytokinesis is the process of division of cytoplasm of the cell. Cytokinesis divides cytoplasm and organelles including nuclei into its daughter cells.
2) DNA is a double-stranded molecule, while RNA is a single-stranded molecule. ... DNA and RNA base pairing is slightly different since DNA uses the bases adenine, thymine, cytosine, and guanine; RNA uses adenine, uracil, cytosine, and guanine.
3) The nucleosome it is the complex that it is made up of DNA wrapped around histonic proteins. In particular a nucleosome unit it is made of 147pb of DNA wrapped around an histonic core made of 8 histon proteins 8 (H2A. ... So, no, the nucleosome it is not a nucleotide, but it is made of nucleotides.
4) The main difference between centrosome and centromere is that a centrosome is a cylindrical structure which forms the spindle apparatus by controlling cell's microtubules where the centromere is a DNA region which holds the two sister chromatids together during the cell division.
5) The main difference between haploid cells and diploid cells is diploid cells have two complete sets of chromosomes, while haploid cells only have one complete set of chromosomes. ... A haploid number is the amount of chromosomes inside the nucleus of one chromosomal set.