Question

1. Is the genetic information in the two sister chromatids of the duplicated chromosome genetically identical or different?

2. Are the two cells at the end of mitosis diploid or haploid?

3. Are the four cells at the end of meiosis diploid or haploid?

4. Are daughter cells are genetically identical to each other?

5. Are daughter cells are genetically identical the original parental cell?

Answer 1

Answer 1: Yes, the genetic information in the two sister chromatids of the duplicated chromosome is genetically identical. A sister chromatid is defined as the identical copies, i.e., chromatids formed as a result of DNA replication of a chromosme. These two chromatids join together at centromere to form a homologous chromosome. A chromatid can also be called as 'one-half' of a chromosome and when two such identical chromatids join to each other, are called sister chromatids. However, if non identical chromatids join together to form a chromosome they are non sister chromatids.

Answer 2: Two cells at the end of mitosis can be diploid or haploid depending upon the parent cell. Mitosis can be defined as an equational division which results in formation of two identical daughter cells with respect to each other as well as to the parent cell having same set of chromosomes as present in the parent cell. Purpose of the mitosis is asexual reproduction, cell regeneration and cell growth. So, if the parent cell undergoing mitosis is diploid, it will result in formation of two diploid cells at the end of the division while if the parent cell is haploid, it will result in formation of two haploid cells at the end of the division. In most of the plants and all the animal species, usually diploid cells undergo mitosis to form new diploid cells.

Answer 3: Two cells at the end of meiosis will always be haploid. Meiosis is a two step divisional process with meiosis-I and meiosis-II by which one parent cell is divided into four daughter cells each containing half the number of chromosomes with respect to their parent cell. Meiosis can occur only in diploid cells and results in formation of haploid daughter cells. Meiosis-I is called as reductional division giving rise to two daughter cells having half the number of chromosomes of parent chromosome number. Meiosis-II is said to be an equational division mitosis which results in formation of four daughter cells two from each produced in meiosis-I. Purpose of the meiosis is formation of gametes for sexual reproduction. The daughter cells resulting from meiosis are not genetically identical because they contain half chromosome number.

Answer 4: Mitosis will result in two identical daughter cells because the number of chromosomes in parent cell will be equal to the number of chromosomes in both daughter cells. However, in meiosis one parental cell carries two separate division steps and results in formation of four daughter cells. Meiosis have two parts, Meiosis-I (reductional division) and meiosis-II ( equational division). After Meiosis-I number of chromosomes reduces to half to that of parent cell and after equational division all four cells will have same number of chromosomes to each other but half of parental number of chromosomes. So, meiosis results in identical daughter cells with respect to each other. But they are not identical to parents since they have half number of chromosomes.

Answer 5: Daughter cells are not always genetically identical to the the original parental cell. They are identical in case of mitosis because mitosis results in formation of two daughter cells which are exact copies of parent cell containing same set of chromosomes and hence identical but in meiosis, daughter cells are not identical to their parent cells as meiosis results in formation of four daughter cells each containing half the number of original cell chromosomes.