What would be the result of fertilization if egg and sperm were produced by mitosis rather than meiosis?
The answer is: b. The resulting offspring would have twice as much DNA as the parents. Mitosis results in new cells having the same number of chromosomes as that of the parents. So, if we assume that two cells produced by mitosis fertilizes, then they would have twice the amount of DNA as the parents. This is because both parents give two sets of DNA, so the offspring will have twice as much DNA as the parents. 2n + 2n = 4n. This is what happens if we assume that two such cells fertilized.
Meiosis and fertilization. biology Help ? (:?
Try the link below. It may help (go down to the section on fertilization to start with). Also see the second link--may be more helpful: Meiosis II is pretty much like mitosis, in that the sister chromatids are separated. This results in four daughter cells, each with an 1n chromosome number. In human females, meiosis II in the precursor egg cells never happens until/if a sperm first enters the egg to fertilize it. Fertilization triggers Meiosis II, and then the sperm nucleus unites with the resulting egg nucleus. Thus, the unfertilized “eggs” that a woman sheds each month are not true eggs. Also in human females, division of the cytoplasm is not even. This provides a way of keeping as much cytoplasm as possible with the future egg/zygote. Rather than equal-sized gametes, one big egg and three smaller polar bodies with minimal cytoplasm are formed.
What would happen if gametes were produced by mitosis rather than meiosis?
the sinmplest answer is if everyone did this every generation your chromosme numer would double since during the fertilzation process the chromosomes from teh motheer and dad join together. Look at it this way...at present you have 46 chromosomes. If meiosis did not occur your egg or sperm would have the ame numer. Hence when you reproduce, your children would have 92 chromosomes andthen your grandchildren 192 chromosomes. As you can see this would not be possible to maintain these vast numbers of chromosmes for very long...though some plants particular those tghat produce flowers for show (daylilies or example) or some fruits have been forced to become tetroid (have 4 chromosomes instaed of 2) in order to produce bigger fruits or flowers.
What would be the result of fertilization if egg and sperm were produced by mitosis rather than meiosis?
Since meiosis produces cells with only half as much chromosomes as the cells produced by mitosis, the zygote would have double of everything. So that would mean double the number of eyes, ears, arms, organs etc. because you're coding for double the number of chromosomes in a normal cell.
Why cant sex cells be produced by mitosis?
Consider the purposes of each type of division. In mitosis, due to the chromosomes aligning in single file, complimentary halves go to each new cell and the chromosome number remains the same. In addition, each new daughter cell is genetically identical to the parent cell. In Meiosis, the chromosomes first group in homologous pairs during Prophase I. Then, in Metaphase I, the homologous pairs align and one member of each pair is pulled to each side of the cell. This reduces the chromosome number to 50% of the original amount. Let's talk about humans and their 46 chromosomes. If each sperm and egg also had 46 chromosomes, when the sperm fertilized the egg, the chromosome number would double to 92 ... next generation to 184 and so forth. After only a couple of generations, I think we'd have a lot of very strange people walking around. So, in Meiosis, the 23 homologous pairs align and one member of each pair goes to each half of the cell. (for simplicity sake, I'm skipping the second stages of Meiosis). That cuts the chromosome number to 1/2, or 23 or 50% of the original number of chromosomes, in each new reproductive cell. THEN, when the sperm fertilizes the egg, it adds its 23 chromosomes to the egg's 23 and we are back at 46.
How can fertilization possibly work when the number of chromosomes in the egg is different than in the sperm?
The issue isn't the number of chromosomes itself, so much as pairing and proper segregation. The progeny of such crosses are often lethal, and when they're not, they're usually infertile. Still, sometimes they survive. Theoretically (emphasis on theoretically), this is one way how chromosome numbers can change. Theoretically, if they stabilize, are neutral or advantageous, and there are factors leading driving speciation (e.g. migration, geographic separation, divergent selection), you may end up with species with different chromosome numbers. Elements of this process can be demonstrated in a lab and I'm sure there are comparative genomics that have formulated a likely pathway through how these events occur.I've actually worked with such materials. Here's how we altered some chromosome numbers in soybean, from 40 to 42. This is artificial and would never happen in nature, but it's an experimental example of how you can cross two species with very different chromosome numbers, and end up with a product with a new chromosome count. This figure is out of my MS thesis.What happened with each stage of crossing back to soybean was chromosomes were lost. However, recombination occurs, and eventually the genome stabilized (well, mostly). Note that even the intermediate lines are cross-fertile, even if the progeny they produce aren't very vigorous.At the cytogenetic level, what's happening is a bunch of messed pairing during meiosis, followed by messed up segregation. In normal diploids, bivalents are a sign of proper fertilization, pairing, and segregation. However, as the figure shows, with additional chromosomes, you start to get univalents and quadrivalents (and in the cases where you have even more genomes, rare pentavalents and hexavalents and so on).DNA Damage
What is random fertilization, and how does it contribute to variation within species?
I know this question relates specifically to what goes on in the Womb but there is another angle to it.Evolution by selection, is a combination of randomness and lawfulness. There is first a “random” process—the occurrence of mutations that generate an array of genetic variants, both good and bad and then a “lawful” process—natural selection—that orders this variation, keeping the good and winnowing the bad.This brings up what is surely the most widespread misunderstanding about Darwinism: the idea that, in evolution, “everything happens by accident”. Quite the opposite. If suddenly evolution was forced to depend on random mutations alone, species would quickly degenerate and go extinct. Chance alone cannot explain the marvelous fit between individuals and their environment.The raw materials for evolution—the variations between individuals—are indeed produced by chance mutations or in this case random fertilisation since I am presuming that the gametes may have slight differences as does the egg.These mutations/random fertilisations occur willy-nilly, regardless of whether they are good or bad for the individual. It is the filtering of that variation by natural selection that produces adaptations, and natural selection is manifestly not random. It is the powerful molding force, accumulating genes that have a greater chance of being passed on than others, and in so doing making individuals ever better able to cope with their environmentI would be interested to hear how this works in the Womb - the variations are apparent. I have two daughters and they couldn't be more different.
What type of cells does mitosis produce?
Mitosis is also called as equational division because in this type of division, the no. Of chromosomes is same in the daughter cells, as it is in the mother cell.In somatic cells, that is, in all cells of the body except reproductive cells, mitosis takes place because the cell has to keep chromosome no. Constant. In this type of cell division, the daughter cells produced are exact copies of mother cells. Their DNA map is exactly same. Hence we can call them clones. It is observed in all somatic cells except nerve cells, which never divide to produce daughter cells.In reproductive cells like germinal epithilium of ovary or testis, meiosis takes place as here, mother cell produces daughter cells with half no. Of chromosomes present in the mother cell. Hence it is also called as reductional cell division.Hope this answer will prove helpful to you
WHY IS MITOSIS INADEQUATE IN PRODUCING SEX CELLS?
Mitosis is an asexual method of dividing the cell's DNA. The amount of genetic material remains the same. Sex cells have limited amounts of genetic material, so that when combined, will produce a cell with a full amount of DNA. The only way to produce a sex cell is through meiosis, which is considered a sexual method of dividing the cell's DNA. Meiosis divides the genetic material twice, while mitosis only divides the genetic material once. After the genetic material is divided, the DNA has the ability to copy itself. In the case of mitosis, it will copy the 1/2 that is remaining, thus producing a full amount of DNA. In the case of meiosis, it will copy the 1/4 that is remaining, only producing 1/2 of the total DNA. Thus, sex cells only contain 1/2 of the total DNA for any organism.
If reproductive cells were made by mitosis instead of meiosis, what would happen when a sperm cell and egg cell joined to make a new cell?
Mitosis results in the formation of diploid cells, i.e. (in humans) each daughter cell would have 23 pairs of homologous chromosomes, or 46 chromosomes total. Meiosis results in the formation of haploid cells, i.e. each daughter cell would have only 23 total chromosomes, none of which are in a homologous pair.If gametes (sperm and egg) were made by mitosis, then they would be diploid. If a diploid sperm fused with a diploid egg, then the resulting zygote would be tetraploid (46 pairs of chromosomes, or 92 chromosomes total). A tetraploid zygote is not viable and will most likely miscarriage.