Term
| Cell division and cell cyclep |
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Definition
| the continuity of life depends on the reproduction of cells. via cell division. the cell division occurs as part of the cell cycle in which a parent cell divides into 2. |
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Definition
| a cell's genetic information. in prokaryotes the genome is often a single DNA molecule. in eukaroyotes the genome consist of several DNA molecules |
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Definition
| DNA molecules are packed into. |
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Definition
| humans have 23 chromosomes, half the number in a somatic cell |
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Definition
| all body cells, except the reproductive cells. humans have 46 chromosomes made up of two sets of 23. |
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| The DNA protein complex organized into a long thin fiber in chromosomes. after the DNA duplicates chromotin condeses coiling and folding to make a smaller package. |
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Definition
| each duplicated chromosomes consist of 2 sister chromatids which contain identical copies of the chromosomes DNA. |
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Definition
| where the sister chromatids meet. in the middle is the centromere. |
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Definition
| the process of the formation of the two daughter nuclei |
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Definition
| mitosis is usually followed by division of the cytoplasm known as cytonkinesis. these processes take one cell and produce two cells that are the genetic equivalent of the parent |
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Definition
| yields 4 daughter cells each with half the chromosomes of the parent, reduces 46 chromosomes to 23 in humans. |
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Definition
| 90% of cell cycle. 3 phases- 1. g1 phase "first gap" which is centered on growth 2. the s phase "synthesis" when DNA synthesis takes place and the chromosomes are duplicated. 3. the g2 phase "second gap" where the cell completes preparations for cell division. all 3 subphases contain nuclear envelope |
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Term
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Definition
| prophase, prometaphase, metaphase, anaphase, telophase |
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Definition
| chromosomes have been duplicated but are loosely packed. the centrosomes have been duplicated and begin to organize. microtubules into astar "star". |
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Definition
| the chromosomes are tightly coiled with sister chromatids joined together. the nucleoli disappear. the mitotic spindle begins to form and appears to push the centrosomes away from each other towards opposite ends of the cell. |
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Term
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Definition
| the nuclear envelopes fragments and microtubules from the spindle interact with chromosomes. microtubules from one pole attach to one of two kinetochores special regions of the centromere where microtubules from the other pole attach to the other kinetochorie. |
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Definition
| the spindle fibers push the sister chromatids until they are all arranged at the metaphase plate- an imaginary plate equidistant between the poles. |
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Definition
| the centomeres divide separating the sister chromatids. each is now pulled to the pole to which it is attached by the spindle fibers. by the end the two poles have equivalent collections of centrosomes. |
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Definition
| the cell continues to elongate as free spindle fibers from each centrosome push off each other. 2 nuclei begin to form surrounded by the fragments of the parents nuclear envelope. chromatin becomes less tightly coiled. cytokinesis division of the cytoplasm begins. |
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Definition
| fibers composed of microtubules and associated proteins is a major driving force in mitosis. |
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Definition
| the kinetochores of the joined sister chromatids face in opposite directions during prometaphase some spindle microtubules attach to the kinetochores |
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Definition
| microtubules are responsible for lengthening the cell along the axis defined by the poles. |
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Definition
| the appearance of the cleavage furrow in the cell surface near the old metophase plate on the cytoplasmic side of the cleavage furrow a contractile ring of actin microfiliments and the motor protein myosin form. |
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Definition
| prokaryotes reproduce by binary fission not mitosis. most bacterial genes are located on a single bacterial chromosome which consists of a circular DNA molecule and associated proteins. |
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Definition
| the binary fission chromosome replication begins at one point in the circular chromosome. |
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Term
| two types of unicellular algae |
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Definition
| in dinoflagellates replicated chromosomes are attached to the nuclear envelope. in diatoms the spindle develops within the nucleus. |
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Term
| cell cycle control system |
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Definition
| the distinct events of the cell cycle are directed by distinct cell cycle control system. there are check points in the cell cycle that regulate giving stop and go signals. 3 major check points are g1, g2, and m phases. |
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Term
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Definition
| g1 check point is the restriction point in mammalian cells and is the most important. if the cells receive a go ahead signal it usually completes the cell cycle and divides. if it does not receive a go ahead signal the cell exits the cycle and switches between non-dividing state "the g 0 phase". liver cells can be called back to the cell cycle by external cues but highly specialized nerve and muscle cells never divide. |
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Term
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Definition
| in the abundance and activity of control molecules pace the cell cycle. some of these molecules are protein kinases that activate or deactivate other proteins by phosephorylating. the levels of these kinases are present in constant amounts but these kinese require a second protein, a cyclin, to become activated. |
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Term
| cyclin dependent kinases (Cdks) |
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Definition
| the complex of kinases and cyclin forms this. |
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Term
| MPF (maturation or M phase promoting factor) |
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Definition
| peaks in the activity of one cyclin Cdk complex correspond to peaks in cyclin concentration. MPF triggers the cells passage past the g2 check point into the M phase. MPF promotes mitosis by phosphorylating a variety of other protein kinases. MPF stimulates fragmentations of the nuclear envelope, it also triggers the breakdown of cyclin dropping cyclin and MPF levels during mitosis and inactivating MPF. |
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Definition
| insures that all the chromosomes are properly attached to the spindle at the metaphase plate before anaphase. this insures that daughter cells do not end up with missing or extra chromosomes. a signal to delay anaphase originates at kinetochores that have not yet attached to spindle microtubules. when all kinetechores are attached the apc ativates triggering breakdown of cyclin and inactivation of proteins uniting sister chromatids together. while some signals originate from inside the cells others from outside. |
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Term
| extra chemical and physical factors and growth factors |
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Definition
| a variety of extra chemical and physical factors can influence cell division. particularly important for mammalin cells are growth factors, proteins released by one group of cells that stimulate other cells to divide. each cell type probably responds specifically to a certain growth factor or combination of factors. |
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Term
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Definition
| cultured cells normally divide until they form a single layer on the inner surface of the culture container. |
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Term
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Definition
| to divide cells must be at anchored to a substaratum typically the extra cellular matrix of a tissue. control appears to be mediated by connections between the extra cellular matrix and plasma membrane proteins and cytoskeleton elements. |
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Definition
| divide excessively and invade other tissues because they are free of the bodies control mechanisms. |
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Definition
| the abnormal behavior of cancer cells begins when a single cell in a tissue undergoes a transformation that converts it from a normal cell to a cancer cell. |
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Definition
| when the abnormal cells remain at the originating site. |
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Definition
| when the cells leave the original site to impair the functions of one of more organisms. in addition to chromosomal and metabolic abnormalities cancer cells often lose attachment to nearby cells are carried by the blood lymph system to other tissues and start more tumors in an event called matastasis. |
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Definition
offspring also differ somewhat from parents and siblings, demonstrating variation |
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Term
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Definition
| The transmission of traits from one generation to the next is called heredity or inheritance |
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Term
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Definition
Genes are specific segments of DNA in the genome Genetic information is transmitted as specific sequences of the 4 Deoxyribonucleotides (A,C,G&T) in DNA This is symbolic information of letters in which words and sentences are translated into menta ima Most genes program cells to synthesize specific enzymes and other proteins that produce an organism's inherited traits |
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Term
In plants and animals, genes are transmited how? |
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Definition
Sperm and ova (unfertilized eggs) transmit genes from each parent Afer fertilization (fusion) of a sperm cell with an ovum, genes from both parents are present in the nucleus of a fertilized egg |
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Term
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Definition
| each chromosome has hundreds or tousands of genes, each at a specific location, it's called locus |
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Term
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Definition
| a single individual passes along copies of all its genes to its offspring. Single-celled eukaryotes reproduce asecually by mitotic cell division to produce two identical daughter cells. Even some multicellular eukaryotes, like hydram can reproduce by budding cells produced by mitosis. Each cell is a clone |
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Definition
| compared to asexual reproduction resluts in greater variation among offspring. Two parents give rise to offspring that have unique combinations of genes inherited from the parents. Offsprign of secual reproduction vary genetically from their sibilings and from both parents |
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Term
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Definition
| in humans, each somatic cell (all cells other than sperm or ovum) has 46 chromosomes. Each fhromosome can be distinguised by its size, position of the centromere, and by pattern of staining with certain dyes |
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Term
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Definition
display of the 46 chromosomes shows 23 pairs of chromosomes, each pair with the same length, centromer position, and staining patter. |
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Term
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Definition
| Pairs carry genes that control the same inherited characters |
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Term
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Definition
| ordered displays of an individual's chromosomes, are often prepared with lymphocytes |
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Term
| the exception to the homologous chromosome |
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Definition
| the Sex Chromosomes, the X and the Y |
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Term
| Human Femal sex chromosomes versus Male |
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Definition
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Term
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Definition
| the other 22 chromosomes other than the sex chromosomes |
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Term
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Definition
| Sperm cells or ova which have only one set of chromosomes - 22 autosomes and an X or a Y |
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Term
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Definition
a cell with a single chromosome set. For example: by means of sexual intercourse, a haploid sperm reaches and fuses with a haploid ovum (for humans, the haploid number of chromosomes is 23) |
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Term
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Definition
| These cells fuse (syngamy) resulting in fertilization |
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Term
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Definition
| The fertilized egg (zzygote) now has two haploid sets of chromosomes bearing genes from the maternal and paternal family lines |
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Term
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Definition
the zygote and all cells with two sets of chromosomes are diploid cells For humans, the diploid number of chromosomes is 46 |
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Term
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Definition
As an organism develops from a zygote to a secually mature adult, the zygote's genes are passed on to all somatic cells by mitosis *Gametes, which develop in the gonads, are not produced by mitosis |
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Term
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Definition
gamestes undergo the process of meiosis in which the chromosome number is halved Human sperm or ova have ahaploid set of 23 different chromosomes, on eform each homologous pair |
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Term
| Alternation of Generation |
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Definition
Plants and some algae have athird type of life cycle, alternation of generation. This life cycle includes both haploid (gametophyte) and diploid (sporophyte) multicellular stages Meiosis by the sporophyte produces haploid spores that develop by mitosis into the gametophyte gametes produced via mitosis by the gametophyte fuse to formt he zygote which produces the sporophyte by mitosis |
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Term
Difference between Mitosis and Meiosis (basic) |
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Definition
Meiosis has Meiosis 1 and meiosis 2 |
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Term
| Division in meiosis I 4 pahses |
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Definition
Prophase, metaphase, anaphase, and telophase During the preceding interphase the chromosomes are replicated to form sister chromatids. These are genetically identical and joined at the centromere. Also, the single centrosome is replicated |
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Term
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Definition
| the chromosomes condense and homologous chromosomes pair up to form tetrads. In a process called synapsis, speical proteins attach homologous chromosomes gihgtly goether. At several sites teh chromatids of homologous chromosomes are crossed (chiasmata) and segments of the chromosomes are traded. A spindle forms from each centrosome and spindle fibers attache to kinetochores on the chromosomes begin to move the tetrads around. |
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Term
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Definition
| the tetrads are all arranged at the metaphase palte. Microtubules from one pole are attached to the kinetochore of one chromosome of each tetrad, while those from the other pole are attached to the other |
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Term
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Definition
| the homologous chromosomes separate adn are pulled twoard opposite poles |
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Term
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Definition
| movement of homologous chromosomes continues until there is a halpoid set at each pole. 8each chromosome consists of linked sister chromatids. Cytokinesis by the same mechanisms as mitosis usually occurs simultaneously. In some species, nuclei may reform, but there is no further replication of chromosomes. |
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Term
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Definition
| very similar to mitosis; during prophase II a spindle apparatus forms, attaches to kinetochores of each sister chromatids, and moves them around. Spindle fibers from one pole attach to the kinetochore of one sister chrmatid and those of the other pole to the other sister chromatid |
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Term
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Definition
| The sister chromatids are arranged at the metaphase plate. the kinetochores of sister chromatids face opposite poles. At anaphase II, the centomeres of sister chromatids separate and the now separate sisters travel toward opposite poles |
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Term
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Definition
| separated sister chromatids arrive at opposite poles. Nuclei form around the chromatids. Cytokinesis separates the cytoplasm. At the end of meiosis, there are four haploid daughter cells |
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Term
| 3 major differences between Mitosis and meiosis |
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Definition
1) the chromosome number is reduced by half in meiosis, but not in mitosis 2) Mitosis produces daughter cells that are genetically identical to the parent adn to each other 3) Meiosis produces cells that differ from the parent and each other |
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Term
| Three events, unique to meiosis, occur during the first division cycle |
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Definition
1) during prophase 1 homologous chromosomes pair up in a process called synapsis. A protein zipper, the synaptonemal complex, holds homologous chromosomes together tightly. Later in prophase I, the joined homologous chromosomes are visible as a tetrad. At X-shaped regions called chiasmata, sections of nonsister chromatids are exhcnaged. Chiasmata is the physical manifestation of crossing over, a form of genetic rearrangement. 2) At metaphase I homologous pairs of chromosomes, not indiviual chromosomes are aligned along the metaphase plate (in humans, you would see 23 tetrads) 3) at anaphase 1, it is homologous chromosomes, not sister chromatids, that separate adn are carried to opposite poles of the cell. Sister chromatids remain attached at the centromere until anaphase II. The porcesses during the second meiotic division are virtually identical to those of mitosis |
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Term
| Modern Genetics began with... |
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Definition
| Gregor Mendel in an abbey garden in around 1857 |
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Term
| What did Mendel begin breeding at first to look at inheritance? |
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Definition
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Term
| Pea plants have several advantages for genetics... |
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Definition
Pea plants are available in many varieties with distinct heritable features (characters) with different variants (traits). Another advantage of peas is that mendel had strict control over which plants mated with which. Each pea plant has male (stamens) and femals (carpal) sexual organs. In nature, pea plants typicaly self-fertilize, fertilizing ova with their own sperm. However, Mendel could also move pollen from one plant to anther to cross-pollinate plants |
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Term
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Definition
| cross two contrasting, true breeding pea varieties |
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Term
| P Generation, F1 Generation, F2 generation (monohybrid) |
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Definition
P generation: the true-breeding parents F1 generation: the P generation hybrid offspring F2 Generation: F1 hybrids to self-pollinated to produce this the next generation |
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Definition
when a cross of purple colored flower plants with white colored flower plants was carried, the progeny in teh F1 hybrids all had purple flowers, just a purple as one of the purple-flowered parent. When Mendel allowed the F1 plants to self-fertilize, the F2 generation included both purple-flowered and white-flowered plants. The white trait, absent in the F1 , reappeared in the F2. Based on a large sample size, Menedel recorded 705 oyple, F2 plants and 224 white F2 plants from the original cross. Thus crosses produced a 3/1 ratio of traits in the F2 offspring. mendel reasoned that the heritable factor for white flowers was present in the F1 plants, but it did not affect flower color. Purple flower is a Dominant trait and white flower is a recessive trait. |
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Term
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Definition
Mendel developed a hypothesis to explain these results that consisted of 4 related ideas: 1) alternative version of allele (gene) account for variations in inherited characters. We know now that different alleles vary somewhat in the sequence of nucleotides at the specific locus of a gene. 2) for each character, an organism inherits 2 alleles, one from each parent. these homologous loci may be identical, as in the true-breeding plants of the P generatiion. 2) if the two alleles differ, then one, the dominant allele, is fully expressed in appearance. the other, the recessive allele, has no noticeable effect. 4) the two alleles for each caracter segregate during gamete production --> the separation of alleles into separate gametes is summarized as Mendel's low of segregation |
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Term
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Definition
| predicts the results of a genetic cross between individuals of known GENOTYPE |
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Term
Homozygous Versus Heterozygous Phenotype versus Genotype |
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Definition
Homozygous: an organism with two identical alleles for a character Heterozygous: organisms with two different alleles for a character Phenotype: a description of an organism's traits Genotype: a description of its genetic makeup Two organisms can have the same phenotype but have different genotypes if one is homozygous dominant adn the other is heterozygous |
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Term
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Definition
| breeding a homozygous recessive with dominant phenotype, but unkown geneotype, can determine the identity of the unknown allele. |
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Term
| Monohybrid versus dihybrid |
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Definition
Monohybrid: mendel's expheriments that followed the inheritance of flower color or other characters focused on only a single character Dihybrid:he conduced other experiments in which he followed the inheritance of two different characters |
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Term
| Law of Independent Assortment |
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Definition
The independent assortment of each pair of alleles during gamete formation. (each character appeared to be inherited independently with 9:3:3:1 ratio) |
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Term
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Definition
| where hterozygotes show a distinct intermediate phenotype, not seen in homozygotes. This is not blended in heritance because the traits are separable (particulate) as seen in ruther crosses. Offispring of a cross between heterozygous will show three phenotypes: both parentals adn the heterozygote. |
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Term
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Definition
| Complete and incomplete dominance are part of a spectrum of relationships among alleles. |
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Term
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Definition
| Two alleles affect the phenotype in separate, distinguishable ways. |
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Term
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Definition
| In which individuals are born with extra fingers or toes, is due to an allele dominant go the recessive allele for five digits per appendage. |
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Term
| Dominance/excessiveness relationship have 3 important points |
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Definition
| 1) They range from complete dominance, though various degrees of incomplete dominance, to codominance2) They reflect the mechanisms by which specific alleles are expressed in the phenotype and do not involve the ability of one allele to subdue another at the level of DNA3) They do not determine or correlate with the relative abundance of alleles in a population |
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Term
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Definition
| Matching Blood: if the donor’s blood has an A or B oligosaccharide that is foreign to the recipient, antibodies in the recipient’s blood will bind to the goreign molecules, cause the donated blood cells to clump together, and can kill the recipient. Blood group AB type individuals are called “universal acceptors” and O type are called “universal donors” |
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Term
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Definition
| Affecting more than one phenotypic character. For example; the wide-ranging symptoms of sickle-cell disease are due to a single gene |
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Term
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Definition
| A gene at one locus alters the phenotypic expression of a gene at a second locus. For example; in mice and many other mammals, coat color depends on two genes. One, the epistatic gene, determines whether pigment will be deposited in hair or not. Presence (C) is dominant to absence (c) The second determines whether the pigment to be deposited in black or brown. B dominant to b. An individual that is cc has a white (albino) coat regardless of the genotype of the second gene |
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Definition
| Vary in a population along a continuum |
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Term
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Definition
| The additive effects of two or more genes on a single phenotypic character. For example: skin color in humans is controlled by at least three different genes. Imagine that each gene has two alleles, one light and one dark, that demonstrate incomplete dominace. AN AABBCC individual is dark and aabbcc is light |
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Term
| Phenotype depends on what? |
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Definition
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Term
| Multifactorial Characters |
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Definition
| Environment contributes to their quantitative nature |
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Term
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Definition
| Rather than manipulate mating patterns of people, geneticists analyze the results of mating by pedigree analysis. Which has information about the presence/absence of a particular phenotypic trait is collected from as many individuals in a family as possible and across generations. The distribution of these characters is then mapped on the family tree. Help to understand the past and predict the future. |
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Term
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Definition
| While heterozygotes may have no clear phenotypic effects, they are carriers who may transmit a recessive allele to their offspring. So they are not physically showing the gene but they have it. |
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Definition
| Which strikes one of every 2,500 whites of European descent. One in 25 whites is a carrier. The normal allele codes for a membrane protein that transports Cl- between cells and the environment. If these channels are defective or absent, there are abnormally high extracellular levels of a chloride that causes the mucus coats of certain cells to become thicker and stickier than normal. This mucus build-up in the pancreas, lungs, digestive track, and elsewhere favors bacterial infections. Without treatment, affected children die before five, but with treatment can live past their late 20s |
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Term
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Definition
| Disease is another lethal recessive disorder. It is caused by a dysfunctional enzyme that fails to break down specific brain lipids. The symptoms begin with seizures, blindness, and degeneration of motor and mental performance a few months after birth. Inevitably, the child dies after a few years. Among Ashkenazic Jews this disease occurs in one of 3,600 births, about 100 times greater than the incidence among non-Jews or Mediterranean Jews |
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Definition
| Most common inherited disease among blacks. It affects one of 400 African Americans. It is caused by the substitution of a single amino acid in hemoglobin. When oxygen levels in the blood of an affected individual are low, sickle-cell hemoglobin crystallizes into long rods. This deforms red blood cells into a sickle shape. This sickling creates a cascade of symptoms, demonstrating the pleitropic effects of this allele. Doctors can use regular blood transfusions to prevent brain damage and new drugs to prevent or treat other problems. |
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Term
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Definition
| Form of dwarfism, has an incidence of one case in 10,000 people. Heterozygous individuals have the dwarf phenotype. Those who are not achodroplastic dwarfs, 99.99% of the population are homozygous recessive for this trait. |
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Definition
| Are much less common than lethal recessives because if a lethal dominant kills an offspring before it can mature and reproduce, the allele will not be passed on to future generations |
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Term
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Definition
| Degenerative disease of the nervous system. Is dominant lethal allele has no obvious phenotypic effect until an individuals is about 35 to 45 years old. The deterioration of the nervous system is irreversible and inevitably fatal. Found on Chromosome 4. |
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Term
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Definition
| These have a genetic compent plus a significant environmental influence. Multifactorial disorders include heart disease, diabetes, cancer, alcoholism, and certain mental illnesses. The genetic component is typically polygenic. |
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Term
T.H. Morgan's groups shwed that bgenes are located on chromosomes and so what are the candidates fro the gentic material? |
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