Final Exam

addition rule - A rule of probability stating that the probability of any one of two or more mutually exclusive events can be determined by adding their individual probabilitiesalleles - Any of the alternative versions of a gene that may produce distinguishable phenotypic effects.alternation of generations - A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of some plants an algaeamniocentesis - A technique associated with prenatal diagnosis in which amniotic fluid is obtained by aspiration from a needle inserted into the uterus. Th fluid and fetal cells it contains are analyzed to detect certain genetic and congenital defects in the fetusanaphase - The fourth stage of mitosis, in which the chromatids of each chromosome have seperated and the daughter chromosomes are moving to the poles of the cell.anchorage dependence - The requirement that a cell must must be attached to a substratum in order to initiate cell divisionaneuploidy - A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in numberasexual reproduction - The generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, or division of the entire organism into two or more parts). In most cases the offspring are genetically identical to the parent.aster - A radial array of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoing mitosisautosomes - A chromosome that is not directly involved in determining sex; not a sex chromosomeBarr body - A dense object lying inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosomebenign tumor - A mass of abnormal cells with specific genetic and cellular changes such that the cells are not capable of surviving at a new site and generally remain at the site of the tumor's originbinary fission - A method of asexual reproduction by "division in half." In prokaryotes, binary fission does not involve mitosis , in single-celled eukaryotes that undergo binary fission, mitosis part of .the processcarriers - In genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder. The heterozygote is generally phenotypically normal for the disorder but can pass on the recessive allele to offspringcell cycle - An ordered sequence of events in the life cycle, from its origincell cycle control system - A cyclically operating set of molecules in the eukaryotic cell that both triggers and coordinates key events in the cell cyclecell division - The reproduction of cellscell plate - A membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside the new cell wall forms during cytokinesiscentromere - In a duplicated chromosome, the region on each sister chromatid where it is most closely attached to the other chromatin by proteins that bind to the centromeric DNA. Other proteins condense the chromatin in that region, so it appears as a narrow "waist" on the duplicated chromosome.(An unduplicated chromosome has a single centromere, identified by the proteins bound there).centrosome - A structure present in the cytoplasm of animal cells that functions as a a microtubule organizin center and is important during cell division. A centrosome has two centriolescharacter - An observable heritable feature that may vary among individuals.checkpoint - A control point in the cell cycle where stop and go-ahead signals can regulate the cyclechiasmata - The X-shaped microscopically visible region whee crossing over has occurred earlier in prophase I between homologous nonsister chromatids. Chiasmata become visible after synapsis ends, with the two homologs remaining associated due to sister chromatid cohesion.chorionic villus (CVS) - A technique associated with prenatal diagnosis i which a small sample of the fetal portion of the placenta is removed for analysis to detect certain genetic and congenital effects in the fetuschromatin - The complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, chromatin exists in its dispersed form, as a a mass of very long, thin fibers that are not visible with a light microscopechromosome theory of inheirtance - A basic principle in biology stating that genes are located at specific positions (loci) on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patternschromosomes - A cellular structure consisting of one DNA molecule and associated protein molecules. (in some contexts, such as genome sequencing, the term may refer to DNA alone.) A eukaryotic cell typically has multiple, linear chromosomes, which are located in the nucleus. A prokaryotic cell has often has a single, circular chromosome, which is found in the nucleoid, a region that is not enclosed by a membrane.cleavage - (1) The process of cytokinesis in animal cells , characterized by pinching of the plasma membrane. (2) The succesion of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cellscleavage furrow - The first sign of cleavage in an animal cell; a shallow groove around the cell in the cell surface near the old metaphase plateclone - (1) A lineage of genetically identical individuals or cells. (2) In popular usage, an individual that is genetically identical to another individual (3) As a verb, o make one or more genetic replicas of an individual or cell.codominance - The situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable wayscomplete dominanace - The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishablecrossing over - The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosiscrossing over - The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosiscyclin - A cellular protein that occurs in a cyclically fluctuating concentration and that plays an important role in regulating the cell cyclecyclin dependent kinases (Cdks) - A protein kinase that is active only when attached to a particular cyclincystic fibrosis - A human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by excessive secretion of mucus and consequent vulnerability to infection; fatal if untreatedcytokinesis - The division of the the cytoplasm to form two separate daughter cells, immediately after mitosis, meiosis I or meiosis II.deletion - (1) a deficiency in a chromosome resulting from the loss of a fragment through breakage (2) A mutational loss of one or more nucleotide pairs from a genedensity-dependent inhibition - The phenomenon observed in normal animal cells that causes them to stop dividing when they come in contact with one anotherdihybrid cross - A cros between two organisms that are each heterozygous for both of the characters being followed (or the self-pollination of a plant that is heterozygous for both characters).dihybrids - An organism that is heterozygous with respect to two genes of interest. All the offspring from a cros between parents doubly homozygous for different alleles are dihybrids. For example AABB and aabb produce a dihybrid of genotype AaBb.diploid cell - A cell containing two sets of chromosomes (2n), one set inherited from each parent.dominant allele - An allele that is fully expressed in the phenotype of a heterozygoteDown syndrome - A human genetic disease usually caused by the presence of an extra chromosome 21; characterized by developmental delays and heart and other defects that are generally treatable or non-life thrateningduplication - An abberation in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicateddystrophy - A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and loss of muscle tissueepistasis - A type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited geneF1 Generation - The first filial hybrid (heterozygous) offspring arising from the parental (P Generation) crossF2 Generation - The offspring resulting from inbreeding (or self pollination) of the hybrid F1 Generationfertilization - (1) the union of haploid gametes to produce a diploid zygote. (2) The addition of mineral nutrients to the soilG0 (zero) phase - A non-dividing state occupied by cells that have left the cell cycle, sometimes reversiblyG1 Phase - The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis beginsG2 Phase - The second gap, or growth phase, of the cell cycle, consisting of interphase after DNA synthesis occursgametes - A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygotegametes - A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.genes - Discrete units of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses)genetic map - An ordered list of genetic loci (genes or other genetic markers) along a chromosomegenetic recombination - General term for the production of offspring with combinations of traits that differ from those found in either parentGenetics - The scientific study of heredity and hereditary variationgenome - The genetic material of an organism or virus; the complete complement of an organism's or virus's genes along with its noncoding nucleic acid sequencesgenomic imprinting - A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parentgenotype - The genetic makeup or set of alleles of an oganismgenotype - The genetic makeup or set of alleles of an organismgrowth factor - (1) A protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells. (2) A local regulator that acts on nearby cells to stimulate cell proliferation and differentiationhaploid cells - A cell containing only one set of chromosomesHemophilia - A human genetic disease caused by a sex-linked recessive allele resulting in the absence of one or more blood clotting proteins; characterized by excessive bleeding following injuryheredity - The transmission of traits from one generation to the nextheterozygous - Having two different alleles for a given genehomologous chromosomes (or homologs) - A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homolgous chromosome is inherited from the organism's father, the other from the mother. Also called a homologous pair.Homologous pairs at the metaphase plate - A pair of chromosomes of the same length , centromere position, and staining pattern that possess genes for the same characters at the corresponding loci. One homologous chromosome is inherited from the organism's father the other from the organisms father. Also called a homologous pair. An imaginary structure at a a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located.homozygous - Having two identical alleles for a given geneHuntington's Disease - A human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20 years after the onset of symptomshybridization - In genetics, the mating or crossing of two true-breeding varietiesincomplete dominance - The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either alleleinterphase - The period of the cell-cycle when the cell is not dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated , and cell size may increase. Interphase accounts for about 90% of the cell cycleinversion - An abberation in chromosome structure resulting from reattachment of a chromosome from which it originatedkaryotype - A display of the chromosomes pairs of a cell arranged by size and shapekinetochore - A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindlelaw of independent assortment - Mendel's second law , stating that each pair of alleles segregatesor assorts , independently of ech other pair during gamete formation ; applies when genes for two characters are located on different pairs of homologous chromosomes or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes.law of segregation - Mendel's first law stating that two alleles in a pair segregate (seperate from each other) into different gametes during gamete formationlife cycle - The generation-to-generation sequence of stages in the reproduction history of an organism.linkage map - A genetic map based o the frequencies of recombination between markers during crossing over of homologous chromosomeslinked genes - Genes located close enough together on a chromosome that they tend to be inherited togetherlocus - A specific place along the length of a chromosome where a given gene is locatedmalignant tumor - A cancerous tumor containing cells that have significant genetic and cellular changes and are capable of invading and surviving in new sites. Malignant tumors can impair the function of one or more organsmap units - A unit of measurement of the distance between genes. One map unit is equivalent to a 1% recombination frequencymeiosis - A modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cellMeiosis I - The first division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell.Meiosis II - The second division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosomes sets as the original cellmetaphase - The third stage of mitosis , in which the spindle is complete and the chromosomes attached to microtubules at their kinetechores, are all aligned at the metaphase platemetaphase plate - An imaginary structure located at a plane midway between two poles at a cell in metaphase on which the centromeres of all the duplicated chromosomes are locatedmetastasis - The spread of cancer cells to locations distant from their original siteMitosis - A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves replicated chromosome number by allocating replicated chromosomes equally to each of the daughter nucleiMitotic (M) phase - The phase of the cell cycle that includes mitosis and cytokinesismitotic spindle - An assemblage of microtubules and associated proteins that is involved in the movement of chromosomes during mitosismonohybrid cross - A cross between two organisms that are heterozygous for the character being followed (or the self pollination of a heterozygous plant)monohybrids - An organism that is heterozygous with respect to a single gene of interest . All the offspring from a cross between prents homozygous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a monohybrid of genotype Aamonosomic - Referring to the diploid cell that has only one copy of a particular chromosome instead of the normal twompf - Maturation promoting factor (or M-phase promoting factor); a protein complex required for a cell to progress from late interphase to mitosis. The active form consists of cyclin and a protein kinase.multifactorial - Referring to a phenotypical that is influenced by multiple genes and environmental factorsmultiplication rule - A rule of probability stating that the probability of two or more independent events occurring together can be determined by multiplying their individual probabilitiesnondisjunction - An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each otherorigin of replication - Site where the replication of a DNA molecule begins, consisting of a specific of nucleotidesP generation - The true-breeding (homozygous) parent individuals from which F1 hybrid offspring are derived in studies of inheritance P stands for parentalparental types - An offspring that matches one of the true-breeding parental (P Generation) phenotypes; also refers to the phenotype itselfpedigree - A diagram of a family tree with conventional symbols , showing the occurrence of inheritable characters in parents and offspring over multiple generationsphenotype - The observable physical and physiological traits of an organism, which are determined by its genetic makeupphenotype - The observable physical traits and physiological traits of an organism , which are determined by its genetic makeuppleiotropy - The ability of a single gene to have multiple effectspolygenic inheritance - An additive effect of two or more genes on a single phenotypic characterpolyploidy - A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accidental cell divisionprometaphase - The second stage of mitosis, in which the nuclear envelope fragments and spindle microtubules attach to the kinetochores of the chromosomesprophase - The first stage of mitosis, in which the chromatin condenses into discrete chromosomes visible with a light microscope, the mitotic spindle begins to form, and the nucleolous dissapears but the nucleus remains intactPunnet square - A diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotypequantitative characters - A heritable feature that varies continuously over a range rather than either or fashionrecessive allele - An allele whose phenotypic effect is not observed in a heterozygoterecombinant chromosomes - A chromosome created when crossing over combines DNA from two parents into a single chromosome.recombinant types or recombinants - An offspring whose phenotype differs from that of the true-breeding P generation parents; also refers to the phenotype itselfS Phase - The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicatedSeparation of homologs - sex chromosomes - A chromosome responsible for determining the sex of an individual.sex-linked gene - A gene located on either sex chromosome. Most sex-linked genes are on the X- chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosomesexual reproduction - A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from both parents via the gametessickle cell disease - A recessively inherited human blood disorder in which a single nucleotide change in the beta-globin gene causes hemoglobin to aggregate, changing red blood cell shape and causing multiple symptoms in afflicted individualssister chromatids - Two copies of a duplicated chromosome attached to each other by proteins at the centromere and sometimes, along the arms. While joined, two sister chromatids make up one chromosome. Chromatids are eventually seperated in Meiosis II.somatic cells - Any cell in a multicellular organism except a sperm or egg or their precursorssomatic cells - Any cell in a multicellular organism except a sperm or egg or their precursorssynapsis - The pairing and physical connection of duplicated homologous chromosomes during prophase I of meiosisSynapsis and crossing over - The pairing and physical connection of duplicated homologous chromosomes during prophase i of meiosis. The reciprocal exchange of genetic exchange of genetic material between nonsister chromatids during prophase of meiosissynaptonemal complex - A zipper-like structure composed of proteins, which connects two homologous chromosomes tightly along their lengthsTay-Sachs disease - A human genetic disease caused by a recessive allele for a dysfunctional enzyme leading to the accumulation of certain lipids in the brain. Seizures, blindness, and the degeneration of motor and mental performance usually become manifest a few months after birth, followed by death within a few yearstelophase - The fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun.transformation - (1) The conversion of conversion of a normal cell into a cell that is able to divide indefinitely in culture, thus behaving like cancer cell. (Malignant transformation may also describe the series of change in a normal cell in an organism that can change it to a malignant (cancerous cell) cell.) (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. When the external DNA is from a member of a different species, transformation results in horizontal gene transfer.translocation - (1) An aberration in chromosome structure resulting from the attachment of a chromosome fragment to a nonhomologous chromosome (2) During protein synthesis, the third stage in the elongation cycle, when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients to the phloem of vascular plantstrisomic - Referring to a diploid cell that has three copies of a particular chromosome instead of the normal twotrue-breeding - Referring to organisms that produce offspring of the same variety over many generations of self pollinationvariation - Differences between members of the same specieswild type - The phenotype most commonly observed in natural populations; also refers to the individual with that phenotypeX-linked gene - A gene located on the X chromosome ; such genes show a distinctive pattern of inheritancezygote - The diploid cell produced by the union of the haploid gametes during fertilization; a fertilized egg