why is cell division so important (for science hw)?
551447
Cell division or Mitosis is how your body replaces worn out cells.  All cells degrade over time, and if your body could not replace them, then you wouldn't live very long.  Partial cell division, or Meiosis(sp) is necessary for reproduction
701725
In multicellular organisms, growth takes place by mitotic divisions that take place in 4 stages. They are: Prophase, Anaphase, Metaphse and Telophase. This is also observed in humans.\nIn multicellular organisms like yeast, multiple fission or budding takes place.
984504
Cytokinesis is the process whereby the cytoplasm of a single cell is divided to spawn two daughter cells. It usually initiates during the late stages of mitosis, splitting a binucleate cell in two to ensure that chromosome number is maintained from one generation to the next. One notable exception to the normal process of cytokinesis is oogenesis (the creation of an ovum in the ovarian follicle of the ovary), where the ovum takes almost all the cytoplasm and organelles, leaving very little for the resulting polar bodies, which then die. In plant cells, a dividing structure known as the cell plate forms across the centre of the cytoplasm and a new cell wall forms between the two daughter cells.\nThe big difference between animal and plant cell cytokinesis is that the animal cell develops a cleavage furrow that essentially pinches through the middle of the two new cells that will form two separate new cells.  In plant cells there is a new cell wall that begins to form between the two new forming cells called the cell plate.  This cell plate begins at the center of the two new cells and continues to grow outward towards the existing cell wall, finally dividing the one cell into two.
862246
look at your body. When you grow, cells divide and grow almost every second mitosis occurs in yuor own self. that is how you grow, repair yourself, and improve your general figure.
238950
When a cell divides you get a new cell. There are actually four main stages of cell division. They are:\nProphase\nMetaphase\nAnaphase\nTelophase.\n\nIf you want more information, I would suggest trying Wikipedia, or your local library.
795038
Because mitosis is the process where cells divide to perform such activities like cell replacement and repair. Their environment is fairly stable and not dangerous/harmful so they rarely divide. So the damaged cells can stay that way for life due to the slow/non-existent division of mitosis.
910568
During prophase. But it actually doesn't happen in all organisms. Yeast for example has a nuclear duplication and division without ever breaking down the nuclear membrane.
576421
Ermm, the fact that cells are the smallest building blocks of life is the reason that we see things as they are.\n\nThe basis is that all cells contain life and they make what is specified in their DNA/RNA. Heart cells make hearts, lung cells -> lungs, blood cells -> red or white, skin cells -> skin..you get the idea.\n\nI hope I have answered your question, or at least to a certain extent.
463857
well it depend on the species of animal or plant you're studying. in Mammalian cells, The protein mTOR is a serine/threonine kinase that regulates DNA translation and cell division. the availability of a food source for the cell influences mTOR so that when cells are not able to grow to normal size they will not go through cell division. This is just one of the proteins synthesized during different times of a cell cycle to prevent mitosis from occuring. some disrupt the formation of mitotic spindles, some prohibit the cell from going into prophase or metaphase...others work on chemical receptors and hormones released form the cell. google search it, and I hope this has helped :)
246253
The nucleus is the centre for cellular organisation. It contains, in eukaryotes, the genome of the organism; i.e. it is where DNA is found. It is the site of coordination of several molecular processes and as a result, any decisions (speaking in broad terms) would have to be made by it. For instance, if a plant cell is in a condition where there is a repellent chemical, receptors on the plasma membrane will signal this situation through cytoplasmic signalling pathways to the nucleus, where genes whose products regulate the the movement of the cell away from that chemical. Thereofre, everything a cell does is pretty much governed by the nucleus. Here I want you to note that it is not only in the nucles DNA is found; it is also in the chloroplasts and the mitochondria. However, the nuclear genome is the one that plays a much larger role in cell growth, development, survival and differentiation.
980704
You would find that many cells spend the majority of the cell cycle in G0/G1 phase as opposed to the actively dividing root tip sections you saw. \n\nPlease visit the link I have provided from the Univ. of Arizona- it describes the Onion Root Tip as well as each phase. This should reinforce some concepts as well.\n\nGood luck!
298657
Cancer is characterised by mutations in genes that lead to uncontrolled cell growth, dvision and differentiation. Mitosis plays a great role in cancer development in that the cancer cells divide by mitosis, where the the daughter cells are diploid. Meiosis is another kind of division carried out in gametes (sperm cells and egg cells) where a daughter cell is haploid. So, somatic or body cells where cancer is developing divide in an uncontrolled manner by mitosis.
774770
Centrioles are found only in animal cells. Also, in plants, cell division mainly takes place in special regions called meristems. These rapidly dividing areas will either elongate the tips of the plants' stems and roots or expand their width. In animals, cells divide everywhere. Cytoplasmic division is also different in plant cells. Plants divide the two daughter cells by building new cell walls rather than by cleaving (pinching in two) as animal cells do.
196196
Well, as you may already know, the purpose of both mitosis and meiosis is to take one cell and make two cells. Before the cells do this though, they have to make sure that a few things are in order. Obviously, there has to be enough stuff for the 2 cells to each be able to live independently. so, there has to be duplication of a lot of stuff before the first cell (let's call it the parent) divides. One of these things is the genome. These are the chromosomes which are made up of DNA. Once the DNA replicates (makes 2 copies of everything from what the parent originally had), the cell can divide. There are now 4 chromosomes of each type, we started out with our usual 2 of each (most organisms have 2 of each chromosome and they differ slightly from each other-this becomes important for meiosis), then when everything duplicated, we got 4! \n\nIn MITOSIS, the 2 cells that come out of the division (lets call them the daughters), are EXACTLY the same in genetic makeup as the original mother cell. They have the very same DNA and therefore make the same proteins and therefore the cells behave the same. \n\n In MEIOSIS on the other hand, the cells are not the same at all. And in fact, this is the point of meiosis - to make new types of cells. You may know that eggs and sperm are products of meiosis, but you not only get a mixing of genes from your mother (from the egg) and father (from the sperm), but the genes inside the egg and sperm are pre-mixed because of meiosis. Thus, genetic diversity!, and an explanation for why you have traits given to you from your grandmother through your father, even though your father may not have that trait (he carries it in his genes for later mixing). This may be a complicated issue in itself but since we have 2 of every chromosome and therefore 2 of every gene (even before the DNA replication that preceeds mitosis), there's a chance that the 2 copies of the same gene are different, one of which shows up in your father and one which you have that you got from your grandmother throuh your father. The mixing, by the way comes about because after the DNA replicates in preparation for cell division. This is neat and involves chromosomes breaking apart and joining back together. Take a look at the animated movie of meiosis at http://www.biology.yale.edu/animatedMeiosis.nclk - make a point to notice the red and green chromosomes at the beginning and the mixed ones at the end.
907218
Meiosis reduces a cell from a diploid cell to a haploid cell. This is important because if it didn't reduce a diploid to a haploid cell, when fertilization would occur, chromosomes would double and that is bad. Chromosome number is species based.\n\nSexual reproduction requires meiosis.\n\nMeiosis in stages....\n\nMeiosis1\n\nInterphase-same as interphase usually is. \n\nMeiosis I\nProphase I-crossing over (homologous chromosomes switch nonsister chromatids). Also the mitotic spindle fibers start forming from the aster and the nuclear envelope disappears.\n\nMetaphase I-The chromosomes meet together at the metaphasic plate, longest phase outside of interphase.\n\nAnaphase I-the chromosomes stay together (aka no break at centromere) they just don't pair up anymore. The pairs split, one chromosome going one way, the other going the other way.\n\nTelophase I and Cytokinesis-Nuclear envelope may or may not reform once the cleavage furrow or cell plate occur. Understand cytoplasmic inheritance with this as well.\n\nMeiosis II\n\nProphase (No interphase) II-no duplicaiton of chromosomes. The mitotic spindles form again\n\nMetaphase II-Everything goes towards the mitotic plate\n\nAnaphase II-The kinetochore spindles, or mitotic spindles, attach to the kinetochores and separate the chromosomes, bringing one chromatid to one end of the cell, another to the other end of the cell.\n\nTelophase II and cytokinesis-four haploid daughter cells are created. Think about it, meiosis I produces two cells, second division creates 4 because each diploid cell produces two haploids.
80916
============================================================\nMitosis is a special kind of cell division used by eukaryote cells. You will probably find a series of diagrams in your biology text book to show the stages of mitosis; these are:\n\nprophase \nmetaphase \nanaphase \ntelophase \n============================================================\n============================================================\n2. cell division \n\neukaryotic cell \n\na. By mitosis (def).\nb. Sex cells in diploid (def) organisms are produced through meiosis (def). \n\nprokaryotic cell \n\na. Usually by binary fission (def). No mitosis.\nb. Organisms are haploid (def). No meiosis needed. \n============================================================\n\nMore at the links:
794268
To learn how to make media. To learn to culture and split cells. To know contamination when you see it. Microscopy. Cell counting; by Coulter and hemocytometer. And a whole lot more, but these will do for a start.