What is the difference between a chromatid and a chromosome?
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a chromatid forms one part of a chromosome after it has coalesced for the process of mitosis or meiosis. during either process, the word "chromosome" indicates a pair of two exactly identical or "sister" chromatids joined at the central point of each chromatid, called the centromere.\n\na chromosome, by definition, has exactly one centromere. thus when sister chromatids are pulled apart by the mitotic spindle during anaphase - that is, when the centromere joining two sister chromatids splits into two centromeres - then each sister chromatid becomes an independent chromosome.\n\nin non-gametic, non-dividing human cells, there are 23 pairs of chromosomes and thus 46 chromatids.
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Well from Prophase to Telophase the chromosomes are intact, so for most of the M-Phase the chromsomes are visible (except for cytokinesis). Other than the M-Phase the DNA is in chromatin form which is localized in the nucleus making it impossible to visualize the DNA on such items as a karyotype.
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Chromatin is the unbound DNA inside the nucleus.  So its pretty much what form the DNA is in at any time thats not cell division.
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B\n\n\nDuring interphase, the chromosomes are found arranged in the nucleus and appear as a network of long, thin threads, called the chromatin
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two copies of chromosomes ion the same cell
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In prophase 1 the DNA condensates, attaches to the nuclear envelope and crossing over occurs (not necessarily).  Then the chromosomes migrate into metaphase positioning.\n\nIn metaphase 1 the DNA tetrads align and get ready to segregate.\n\nThat's the big difference.\n\nCheers.
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Mitosis is the reproduction of somatic (body) cells, while meiosis is the production of gametes (sex cells).\n\nThe normal cell has a chromosome number of "2n".  For example, a fruit fly has a chromose count of 8, so 8=2n.\n\nFollowing so far? Good.\n\nMitosis:\nMitotic division begins with a cell in Interphase, with a chromosome count of 2n.\nThe chromosomes are not visible right now under the microscope, they just look like a mass of tangled string called chromatin.\n\nIn Prophase, the chromosomes replicate, but remain attatched to their partner by a centromere (kinda look like an x).  Spindle fibres form and the centrioles migrate to the ends of the cell, opposite each other.  Nuclear membrane disappears.\n\nIn Metaphase, the chromosomes line up on the equatorial line (a bunch of x in a row along the middle of the cell), and spindle fibres attatch to each chromatid in the pair (right now, the two parts to the x are individually chromatids, but are together a chromosome).\n\nDuring Anaphase, the spindle fibres pull each daughter chromosome so that the pair of chromatids splits apart and half of them go to one end of the cell, and half to the other.\n\nDuring Telophase, the nucleolus forms and the nuclear membrane forms around the two sets of chromosomes.  A clevage furrow separates the cell into two daughter cells, each having a 2n number of chromosomes.\n\nPhew.  Still following?  Good- that was just Mitosis!\n\nNow for the fun one.  Meiosis.\nMeiosis takes the 2n cell and turns it into FOUR  (4) gametes.\nIn your body, each individual chromosome is part of a homologous pair.  That is, each has a match.  This is why we represent the chromosome number as 2n- There are two sets of n chromosomes.  In our fruit fly, the 2n number is 8, so there are 4 sets of homologous pairs.  Following? Good.\n\nMeiosis in the fruit fly begins with a single cell with 8 chromosomes, and ends with 4 cells with 4 chromosomes each.\n\nWhy does it end with "n" instead of "2n"?  Each gamete provides half the genetic information needed to create the new organism.  You get half your genes from your mother and half from your father.\n\nAnyway, meiosis takes place in two stages: aptly called meiosis 1 and meiosis 2.\n\nMeiosis 1:\nIn Interphase, the cell has roughly the same appearance as it did in Interphase of Mitosis.\n\nIn Prophase 1: The chromosomes duplicate and find their homologous pairs.  Now, the little groups istead of looking like an x, look like an x with four little lines joining, because there are 4 chromatids attached together, called a tetrad.  Understand?  I hope so!\nAt this point, the two chromatids nearest together in the tetrad may "cross over".  In other words, they swap genetic information.  Homologous pairs carry similar, but not identical coding (remember one was from your father, one from your mother).  In this way, you now have 4 chromatids that are each unique in their coding, which allows for genetic variation!  \nCentromers go to opposite ends, and spindle fibres begin to form.  Nuclear membrane disappears\n\nIn Metaphase 1: The tetrads line up on the equatorial line (remember this?)  The spindle fibres attatch to each side of the tetrad.\n\nIn Anaphase 1: The spindle fibres split the tetrads in half, so that 2 chromatids (1 chromosome now) go to one pole of the cell, and 2 chromatids (1 chromosome) go to the other.\n\nIn Telophase 1: The nuclear envelope/membrane reappears around each set of chromosomes, and a cleavage furrow splits the cell into two daughter cells.\n\nAt this point, we now have two daughter cells with "n" for the chromosome count, because there is half the amount of chromosomes we had when we started!\n\nOk, now each daughter cell undergoes meiosis 2, so that at the end we have 4 gametes.\n\nProphase 2:  Nuclear envelope dissappears.  Centroles migrate to the opposite sides of the cells, spindle fibres form.  Remember that the chromosomes are composed of
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In order for crossing over to occur, two different cells are needed, one maternal and one paternal. In mitosis a cell produces two identical daughter cells (no other chromatid to cross with). In meiosis, after DNA replication the two chromatids recombined or cross over.
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Chromosomal DNA is what determines who we are as individuals.  There are 23 pairs of choromosomes.  There are 22 pairs of autosomes which are alike in male and females and then thereis one pair of sex chromosomes.  XX is female.  XY is male.
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Absolutely nothing to do with chromosome count.\n\n>>>> How closely related are humans to apes and \n>>>> other animals?\n\nIt varies depending on the animal obviously. Around 95% relatedness to chimpanzees. Around 92% for gorillas, as little as 80% for orang-utans. It gets progressively less the  more distant the other species are in evolutionary terms.\n\n>>>>How do scientists measure that?\n\nThere are two basic ways. One is to measure the degree of similarity of the genes, that is the functional parts of the DNA. That generally produces figures quite a bit higher than the ones I gave above. The other is to sequence the entire genome, or large stretches of it and compare it that way. Because those long stretches contain non-coding material they are generally more dissimilar between species.\n\n>>>>Are humans related to plants at all?\n\n\nYep. All living things on this planet are related to some degree. IIRC humans share around 15% of their genes with bananas.
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Maybe you could try to be abit more specific, but genes are information MADE of DNA, so "where" is an odd question to ask... \nMaybe you are referring to the difference between euchromatin (hypomethylated and decondensed) and heterochromatin (highly methylated and condensed) ...? If that´s the case, genes are definitely in euchromatin. That´s why heterochromatin is called "silent" DNA.
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Yes, I remember hearing that when people first started looking at chromosomes under the microscopes, they just looked like colored bodies in the cell.  In other words, they stain.  So in that way, "chromo" makes sense.  In fact, I believe "some" means body, so a chromosome is a "colored body".
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The replication of chromosomes does not occur during mitosis. This replication occurs during the S phase of the interphase. Think of the word SYNTHESIS when you think of the S phase. The new strands of DNA in the chromosome are SYNTHESIZED in the S phase.
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Chromatin\nnoun\n\nsubstance forming chromosomes: the substance that forms chromosomes and contains DNA, RNA, and various proteins \n\nMicrosoft® Encarta® Reference Library 2004. © 1993-2003 Microsoft Corporation. All rights reserved.\n\nChromonema\n(plural Chromonemata)\nnoun\n\nchromatid core: the coiled central filament that forms the core of a chromosome strand (chromatid)\n\nMicrosoft® Encarta® Reference Library 2004. © 1993-2003 Microsoft Corporation. All rights reserved.
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Well haploid cells are cells that contain half the number of chromosomes present in the cell while diploid cells are cells that contain the full number of cromosomes present in that cell like in Humans there are 46chromosomes in one cell so since haploid means half the number thus it contains 23chromosomes and since diploid means full number of chromosomes then it means it contains 46chromosomes. Something to note is that haploid cells are usually reproductive cells and diploid cells are usually body cells.
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human cells contain 46 chromosomes\n\nthey go through a process of mitotic division that basically replicates each chromosome, the original and replicated chromosomes then migrate to opposite ends of the cells, and a cell membrane is formed, thus producing two progeny cells, division and the cycle of the cell is complete.\n\n\nmeotic division is a more complex process, but basically, the daughter cells contain 23 chromosomes, that is 1 of each pair of the 46 chromosomes is present in the daughter cell, where, whether it is a sperm or egg cell, when fused together, provide the fused cell with 46 chromosomes\n\n\n\n\nhope it helped you understand it a little better\n\nthere are however, different phases to the division process and if you like I can send you a link, depends on how much you want to know at present?
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dna and genetic coding of chromosomes.