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| 4694969547 | chromosome | in prokaryotes, a DNA molecule containing the organism's genome; in eukaryotes, a DNA molecule complexed with RNA and proteins to form a threadlike structure containing genetic information arranged in a linear sequence; a structure that is visible during mitosis and meiosis | 0 | |
| 4694969548 | mitosis | a form of cell division producing two progeny cells identical genetically to the progenitor cell - that is, the production of two cells from one, each having the same chromosome complement as the parent cell | 1 | |
| 4694969549 | meiosis | the process of cell division in gemetogenesis or sporogenesis during which the diploid number of chromosomes is reduced to the haploid number | 2 | |
| 4694969550 | gamete/spore | a specialized reproductive cell with a haploid number of chromosomes | 3 | |
| 4694969551 | chromatin | the complex of DNA, RNA, histones and nonhistone proteins that make up uncoiled chromosomes, characteristic of eukaryotic interphase nucleus | 4 | |
| 4694969552 | eukaryotes | organisms having true nuclei and membraneous organelles and whose cells divide by mitosis and meiosis | 5 | |
| 4694969553 | nucleus | the membrane-bound cytoplasmic organelles of eukaryotic cells that contains the chromosomes and nucleolus | 6 | |
| 4694969554 | nucleolus | the nuclear site of ribosome biosynthesis and assembly; usually associated with or formed in association with the DNA compromising the nucleolar organizer region. | 7 | |
| 4694969555 | nucleolar organizer region (NOR) | a chromosomal region containing the genes for rRNA; most often found in physical association with the nucleolus | 8 | |
| 4694969556 | prokaryote | organisms lacking nuclear membranes and true chromosomes. Bacteria and blue-green algae are examples of these. | 9 | |
| 4694969557 | nucleoid | the DNA-containing region within the cytoplasm in prokaryotic cells | 10 | |
| 4694969558 | endoplasmic reticulum (ER) | a membranous organelle system in the cytoplasm of eukaryotic cells. In rough __, the outer surface of the membranes is ribosome-studded; in smooth __, it is not | 11 | |
| 4694969559 | ribosome | a ribonucleoprotein organelle consisting of two subunits, each containing RNA and protein molecules. They are the site of translation of mRNA codons into the amino acid sequence of a polypeptide chain | 12 | |
| 4694969560 | mitochondria | the so-called power house of the cell - a self-reproducing, DNA-containing, cytoplasmic organelle in eukaryotes involved in generating the high-energy compound ATP | 13 | |
| 4694969561 | chloroplast | a self-replicating cytoplasmic organelle containing chlorophyll and the site of photosynthesis | 14 | |
| 4694969562 | endosymbiont hypothesis | the proposal that self-replicating cellular organelles such as mitochondria and chloroplasts were originally free-living organisms that entered into a symbiotic relationship with nucleated cells | 15 | |
| 4694969563 | centriole | a cytoplasmic organelle composed of nine groups of microtubules, generally arranged in triplets. They function in the generation of cilia and flagella and serve as foci for the spindle in cell division | 16 | |
| 4694969564 | centrosome | region of the cytoplasm containing a pair of centrioles | 17 | |
| 4694969565 | spindle fibers | cytoplasmic fibrils formed during cell division that attach to and are involved with separation of chromatids at the anaphase stage of mitosis and meiosis as well as their movement toward opposite poles in the cell. | 18 | |
| 4694969566 | centromere | the specialized heterochromatic chromosomal region at which sister chromatids remain attached after replication and the site to which spindle fibers attach to the chromosome during cell division. Location of these during the anaphase portion of cell division. Also known as the primary constriction | 19 | |
| 4694969567 | diploid (2n) | a condition in which each chromosome exists in pairs; having two of each chromosome | 20 | |
| 4694969568 | homologous chromosomes | chromosomes that synapse or pair during meiosis and that are identical with respect to their general loci and centromere placement | 21 | |
| 4694969569 | karyotype | the chromosome complement of a cell or an individual. Often used to refer to the arrangement of metaphase chromosomes in a sequence according to length and centromere position | 22 | |
| 4694969570 | haploid (n) | a cell or an organism having one member of each pair of homologous chromosomes. Also referred to as the gametic chromosome number | 23 | |
| 4694969571 | genome | the set of hereditary information encoded in the DNA of an organism, including both the protein-coding and non-protein-coding sequences | 24 | |
| 4694969572 | locus | the site or place on a chromosome where a particular gene is located | 25 | |
| 4694969573 | allele | one of the possible alternative forms of a gene, often distinguished from other alleles by phenotypic effects | 26 | |
| 4694969574 | zygote | the diploid cell produced by the fusion of haploid gemetic nuclei | 27 | |
| 4694969575 | karyokinesis | the process of nuclear division | 28 | |
| 4694969576 | cytokinesis | the division or separation of the cytoplasm during mitosis or meiosis | 29 | |
| 4694969577 | cell cycle | the sequence of groth phases of an individual cell; divided into G1, S, G2 and M. A cell may temporarily or permanently be withdrawn from it, in which case it is said to enter the G0 stage | 30 | |
| 4694969578 | interphase | in the cell cycle, the interval between divisions | 31 | |
| 4694969579 | G0 phase | a nondividing but metabolically active state that cells may enter from the G1 phase of the cell cycle | 32 | |
| 4694969580 | cohesin | a protein complex that holds sister chromatids together during mitosis and meiosis and facilitates attachments of spindle fibers to kinetochores | 33 | |
| 4694969581 | metaphase | the stage of cell division in which condensed chromosomes lie in a cnetral plane between the two poles of the cell and during which the chromosomes become attached to the spindle fibers | 34 | |
| 4694969582 | kinetochore | a fibrous structure with a size of about 400 nm, located within the centromere. It is the site of microtubule attachment during cell division | 35 | |
| 4694969583 | shugoshins | a class of proteins involved in maintaining cohesion of the centromeres of sister chromatids during mitosis and meiosis. | 36 | |
| 4694969584 | anaphase | stage of mitosis or meiosis in which chromosomes begin moving to opposite poles of the cell | 37 | |
| 4694969585 | disjunction | the separation of chromosomes during the anaphase stage of cell division | 38 | |
| 4694969586 | telophase | the stage of cell division in which the daughter chromosomes have reached the opposite poles of the cell and reverse the stages characteristic of prophase, re-forming the nuclear envelopes and uncoiling the chromosomes. Ends with cytokinesis, which divides the cytoplasm and splits the cell in two. | 39 | |
| 4694969587 | cyclin | in eukaryotic cells, a class of proteins that are synthesized and degraded in synchrony with the cell cycle and regulate passage through stages of the cycle | 40 | |
| 4694969588 | G1/S checkpoint | a point in the G1 phase of the cell cycle when a cell becomes committed to initiating DNA synthesis and continuing the cycle or withdraws into the G0 resting stage. | 41 | |
| 4694969589 | crossing over | the exchange of chromosomal material (parts of chromosomal arms between homologous chromosomes by breakage and reunion. The exchange of material between nonsister chromatids during meiosis is the basis of genetic recmobination | 42 | |
| 4694969590 | synapsis | the pairing of homologous chromosomes at meiosis | 43 | |
| 4694969591 | bivalents | synapsed homologous chromosomes in the first phase of meiosis | 44 | |
| 4694969592 | tetrad | the four chromatids that make up paired homologs in the prophase of the first meiotic division. In eukaryotes, with a predominant haploid stage (some algae and fungi), a tetrad denotes the four haploid cells produced by a single meiotic division | 45 | |
| 4694969593 | reductional division | the chromosome division that halves the number of centromeres and thus reduces the chromosome number by half. The first division of meiosis is an example. | 46 | |
| 4694969594 | dyad | the products of tetrad separation or disjunction at meiotic prophase I. Each one consists of two sister chromatids joined at the centromere | 47 | |
| 4694969595 | equational division | a division stage where the number of centromeres is not reduced by half but where each chromosome is split into longitudinal halves that are distributed into two daughter cells. Chromosome division in mitosis and the second meiotic division are examples. | 48 | |
| 4694969596 | chaisma | the crossed strands of nonsister chromatids seen in diplotene of the first meiotic division. Regarded as the cytological evidence for exchange of chromosomal material, or crossing over | 49 | |
| 4694969597 | nondisjunction | a cell division error in which homologous chromosomes (in meiosis) or the sister chromatids (in mitosis) fail to separate and migrate to opposite poles; responsible for defects such as monosomy and trisomy | 50 | |
| 4694969598 | telophase I | the stage in the first meiotic division when duplicated chromosomes reach the poles of the dividing cell |  | 51 |
| 4694970395 | plasma membrane | an outer covering that defines the cell boundary and delimits the cell from its immediate external environment | 52 | |
| 4694970396 | cell wall | what plants have in addition to the plasma membrane that is an outer covering | 53 | |
| 4694971459 | cell coat (glycocalyx) | the outer covering that most animal cells have over the plasma membrane | 54 | |
| 4694972917 | receptor molecules | act as recognition sites that transfer specific chemical signals across the cell membrane into the cell | 55 | |
| 4694972918 | cytoplasm | the remainder of the eukaryotic cell within the plasma membrane, excluding the nucleus, that contians a variety of extranuclear cellular organelles | 56 | |
| 4694972919 | cytosol | a nonparticulate, colloidal material that surrounds and encompasses the cellular organelles | 57 | |
| 4694973115 | microtubules | help comprise the cytoskeleton and provides a lattice of support to the cell along side microfilaments | 58 | |
| 4694973116 | tubulin | a protein that makes up microtubules | 59 | |
| 4694973289 | microfilaments | help comprise the cytoskeleton and provides a lattice of support to the cell along side microtubules | 60 | |
| 4694973290 | actin | a protein that makes up microfilaments | 61 | |
| 4694974763 | metacentric |  | 62 | |
| 4694975275 | submetacentric |  | 63 | |
| 4694975754 | acrocentric |  | 64 | |
| 4694976122 | telocentric |  | 65 | |
| 4694976733 | p arm | the shorter arm on the centromere | 66 | |
| 4694977141 | q arm | the longer arm on the centromere | 67 | |
| 4694982163 | biparental inheritance | inheritance from two parents | 68 | |
| 4694982750 | sex-determining chromosomes | chromosomes that determine sex | 69 | |
| 4694984184 | S phase | the period during which the DNA is synthesized and this period occurs before the cell enters mitosis | 70 | |
| 4694984185 | G1 phase | 71 | ||
| 4694985076 | G2 phase | 72 | ||
| 4694985644 | sister chromatids | the two parts of each chromosome | 73 | |
| 4695009853 | prometaphase | refers to the period of chromosome movement | 74 | |
| 4695009866 | kinetochore microtubules | the microtubules that are most directly responsible for chromosome migration, and make contact with and adhere to kinetochores | 75 | |
| 4695010172 | daughter chromosome | during anaphase, the migrating chromatids are called _______________________ | 76 | |
| 4695010346 | molecular motors | 77 | ||
| 4695011564 | cell plate | 78 | ||
| 4695011565 | middle lamella | the cell plate laid down during telophase becomes a structure called the _________________________ | 79 | |
| 4695011566 | cell furrow | 80 | ||
| 4695012246 | cell division cycle (cdc) mutations | 81 | ||
| 4695012247 | kinases | the normal products of many of the mutated genes are enzymes called _________________ | 82 | |
| 4695012784 | G2/M checkpoint | the checkpoint where DNA is monitored prior to the start of mitosis | 83 | |
| 4695013787 | M checkpoint | the successful formation of the spindle fiber system and then attachment of spindle fibers to the kinetochores associated with the centromeres are monitored at this checkpoint | 84 | |
| 4695013911 | monads | 85 | ||
| 4695013912 | prophase I |  | 86 | |
| 4695014330 | leptotene stage | the interphase chromatin material begins to condense and the chromosomes become visable | 87 | |
| 4695014331 | chromomeres | localized condensations on a chromosome that resemble beads on a string | 88 | |
| 4695014451 | homology search | 89 | ||
| 4695014452 | zygotene stage | chromosomes continue to shorten and thicken during this stage | 90 | |
| 4695015507 | synaptonemal complex | a more extensive ultrastructurual component begins to form between the homologs | 91 | |
| 4695015508 | pachytene stage | the chromosomes continue to coil and shorten, and further developement of the synaptonemal complex occurs between the two members of each bivalent at this stage | 92 | |
| 4695015795 | diplotene stage | each tetrad consists of two pairs of sister chromatids at this stage | 93 | |
| 4695016188 | diakinesis | the final stage of prophase I where the chromosomes pull farther apart but nonsister chromatids remain loosly associated at the chiasmata | 94 | |
| 4695016189 | terminalization | as separation proceeds in diakinesis, the chiamata move toward the ends of the tetrad | 95 | |
| 4695016352 | metaphase I |  | 96 | |
| 4695016637 | anaphase I | the stage in the first meiotic division during which members of homologous pairs of chromosomes separate from one another. |  | 97 |
| 4695017914 | meiosis II |  | 98 | |
| 4695019455 | prophase II |  | 99 | |
| 4695019608 | metaphase II |  | 100 | |
| 4695020074 | anaphase II |  | 101 | |
| 4695020375 | telophase II |  | 102 | |
| 4695020761 | spermatogenesis | 103 | ||
| 4695020762 | spermatogonium | undifferentiated diploid germ cell | 104 | |
| 4695021079 | primary spermatocyte | the germ cell that undergoes the first meiotic division | 105 | |
| 4695021080 | secondary spermatocytes | the product of the first meiotic division | 106 | |
| 4695021229 | spermatids | the two haploid cells that are produced from meiosis II | 107 | |
| 4695021402 | spermiogenesis | the series of developmental changes that the spermatids go through in order to become highly specialized | 108 | |
| 4695022444 | spermatozoa (sperm) | highly specialized cells | 109 | |
| 4695022445 | oogenesis | 110 | ||
| 4695022446 | ova | eggs | 111 | |
| 4695022774 | primary oocyte | 112 | ||
| 4695022775 | oogonium | 113 | ||
| 4695022891 | first polar body | the dyads at one pole are pinched off with very little surrounding cytoplasm to form the ______________________ | 114 | |
| 4695022892 | secondary oocyte | 115 | ||
| 4695022893 | ootid | 116 | ||
| 4695023028 | secondary polar body | 117 | ||
| 4695023176 | sporophyte stage | 118 | ||
| 4695023177 | gametophyte stage | 119 | ||
| 4695026131 | folded-fiber model | 120 |
