Genetics as it applies to evolution, molecular biology, and medical aspects.
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Here is a question:
All hereditary characters in a cell are passed on from parent-cell to daughter-cell through the process of A. mitosis B. meiosis C. fertilization D. implantation E. gestation
The meiosis, implantation and gestation cannot describe the process. The answer lie between mitosis and fertilization.
Fertilization occurs internally when the sperms meet the ovum as it passes dowm the oviduct and they fuse together. The nucleus of the sperm and the egg must be fused before the genetic materials of the both parents can be effectively transfered to the developing zygote becuase is only the the nucleus that contains all the hereditary materials. With this in mind one could easily conclude that fertilization is the best answer to the question.
If we look at mitosis in the other hand, it is known and accepted widely that mitosis is a type of cell division that result to two daugther cells each the same as the parents nuclues. http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20laboratory/mitosis/mitosis.htm. That type of cell division can occure in the somatic cells unlike the meosis that occurs in the gonads.
The haploid number of chromosom in man is 23 and the diploid number is 46. Is when the 23 chromosom in the sperm joins with the 23 in the ovum that we can have the haploid 46 and that can only happen through fertilization.
But according to "Introduction to Biology WEST AFRICAN EDITION", a biology text book written by D G Mackean with topic on 'CHROMOSOMES AND HEREDITY', I quote from one of the pages:
The cytoplasm of the sperm fuses with of that of the ovum and the male nucleus passes into the ovum, coming to lie alongside the egg nucleus: the zygote is formed, but in many cases there is no fusion of nuclear material at this stage. Each nucleus simultaneously undergoes a mitosis with the axes of the spindle paralle to each other, but at the telophase stage the adjacent chromatides, originally from different parents become enclosed in the same nuclear membrane, thus restoring the diploid number of chromomes. With these texts, I suggest that mitosis describe the process much better than fertilization. Therefore the answer is A and not C as some may think.
To you viewing this thread, what is your own point of view concerning the question?
I would agree that the answer is A-Mitosis. Basically, mitosis is a process where the cell genetic content (2N or diploid) is duplicated. Watson and Crick described the process as semi-conservative. New copies of each chromosome actually contain one strand from the original cell and one new strand, its compliment. The cell now has a 4N number of chromosomes. One complete set of chromosomes separate where re-formation of the membrane separates the cell into two new daughter cells. Each daughter cell contains the same genetic content as the parent cell.
Fertilization is different. It is the process where meiosis has formed cells with half the number of chromosomes (1N or haploid). Sperm and Ova unite to form a cell re-establishing the diploid state. However, this cell is not identical to the parental cell. It is the hybrid of two parent cells, one paternal and one maternal.
That means that after fertilization have occured, the sperm and egg nucleus will not fuse together yet. At least they will have to undergo mitosis before the both nucleus can be fused, thereby passing all their genetic material to the daughter cell (zygote).
5 posts • Page 1 of 1
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