BIOL 150: Exam 3
68 Cards in this Set
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Genome
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The complete complement of an organism’s genes; an organism’s genetic material.
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Binary fission
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The type of cell division by which prokaryotes reproduce; each dividing daughter cell receives a copy of the single parental chromosome.
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Haploid
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A cell containing only one set of chromosomes (n).
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Diploid
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A cell containing two sets of chromosomes (2n), one set inherited from each parent.
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Chromatids
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Duplication of chromosomes leads to replicated structures called chromatids, sister chromatids are joined at the center by centromeres
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Centromere
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The centralized region joining two sister chromatids.
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Chromosome
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A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins
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Mitosis
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A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei
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Cytokinesis
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The division of the cytoplasm to form two separate daughter cells immediately after mitosis
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Cell cycle
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An ordered sequence of events in the life of a dividing eukaryotic cell; composed of the M, G1, S, and G2 phases
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Interphase
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The period in 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 90% of the time of each cell cycle.
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Metaphase
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The stage of mitosis or meiosis in which the chromosomes become aligned on the equatorial plate of the cell
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G1 phase
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The first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.
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G2 phase
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The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs
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S phase
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The synthesis phase of the cell cycle, constituting the portion of interphase during which DNA is replicated
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Spindle
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An assemblage of microtubules that orchestrates chromosome movement during eukaryotic cell division
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Meiosis
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a two-stage type of cell division in sexually reproducing organisms that results in gametes with half the chromosome number of the original cell.
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Gene
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A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).
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Somatic cells
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Any cell in a multi-cellular organism except a sperm or egg cell.
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Gametes
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A haploid egg or sperm cell; gametes unite during sexual reproduction to produce a diploid zygote
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Synapsis
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The pairing and physical connection of duplicated homologous chromosomes during prophase I of meiosis
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Tetrad
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In heredity, a bivalent chromosome that divides into four during meiosis
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Homologous chromosomes
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Chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism’s father, the other from the mother
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Maternal chromosome
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Homologous chromosomes consist of two paired chromosomes; the chromosome that originates from the mother is called the maternal chromosome
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Paternal chromosome
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Homologous chromosomes consist of two paired chromosomes; the chromosome that originates from the father is called the paternal chromosome
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Sister chromatids
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Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II
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Chiasma
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The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis
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Crossing over
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The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis I.
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Photosynthesis
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The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes
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Autotrophs
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An organism that obtains organic food molecules without eating other organisms. Autotrophs use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones
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Heterotrophs
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An organism that obtains organic food molecules by eating other organisms or their by-products.
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Stomata
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A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant
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Mesophyll
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Leaf cells specialized for photosynthesis; located between the upper and lower epidermis in C3 and CAM plants; located between the bundle-sheath cells and epidermis in C4 plants
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Chlorophyll
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A green pigment located within the chloroplasts of plants; chlorophyll a can participate directly in the light reactions, which convert solar energy to chemical energy
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Light dependent reactions
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Those chemical reactions within photosynthesis that require sunlight; light dependent reactions convert solar energy to chemical energy
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Light independent reactions
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Chemical reactions within photosynthesis that do not require sunlight, these reactions generate sugars from the ATP and NADPH that are generated during the light dependent reactions of photosynthesis
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Photophosphorylation
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The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis
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Calvin cycle
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The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate
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Photon
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A quantum, or discrete amount, of light energy
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Rubisco
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Ribulose bisphosphate carboxylase, the enzyme that catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP, or ribulose bisphosphate)
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C3 plants
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A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate
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C4 plants
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A plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compounds, the end-product of which supplies CO2 for the Calvin cycle
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CAM plants
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A plant that uses crassulacean acid metabolism, an
adaptation for photosynthesis in arid conditions.
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Signal transduction
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Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor.
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G protein
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A GTP-binding protein that relays signals from a plasma-membrane signal receptor, known as a G-protein-coupled receptor, to other signal-transduction proteins inside the cell. When such a receptor is activated, it in turn activates the G protein, causing it to bind a molecule of GTP in pl…
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Cyclic AMP
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cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that a common intracellular signaling molecule (second messenger) in eukaryotic cells, for example, in vertebrate endocrine cells
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adenylyl cyclase
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An enzyme that converts ATP to cyclic AMP in response to an extracellular signal
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IP3 (inositol triphosphate)
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The second messenger, which functions as an intermediate between certain nonsteroid hormones and the third messenger, a rise in cytoplasmic Ca++ concentration
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DAG (diacyl glycerol)
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Serves as a second messenger in stimulating the activity of protein kinase C
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Phosphodiesterase
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An enzyme that deactivates cyclic AMP
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Character (Mendelian)
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An inherited feature under the control of a single locus (although perhaps modified by genes at other loci); e.g. hair color
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Trait
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Variation within a characteristic, how the genetic character is displayed in an individual
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Locus
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A particular place along the length of a certain chromosome where a given gene is located
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Alleles
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One of several alternate forms of a particular gene, usually giving rise to a characteristic form of phenotype (e.g., purple or white flower color)
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Homozygous
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Having two identical alleles for a given genetic character
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Heterozygous
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Having two different alleles for a given genetic character
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Phenotype
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The appearance of the character within an organism
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Genotype
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The genetic makeup of an organism
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Monohybrid cross
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A breeding experiment that uses parental varieties differing in a single character
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Dihybrid cross
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A breeding experiment in which parental varieties differing in two traits are mated
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Dominant
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In genetics, denoting an allele possessed by one of the parents of a hybrid which is expressed in the latter to the exclusion of a contrasting allele (the recessive) from the other parent. An allele that can determine the phenotype of heterozygotes completely, so that they are indistingui…
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Recessive
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An allele expressed only in homozygotes and completely masked in heterozygotes
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F1 generation
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The first filial or hybrid offspring in a genetic cross-fertilization
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F2 generation
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Offspring resulting from interbreeding of the hybrid F1 generation
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Test cross
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Breeding of an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring determines the unknown genotype
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Autosomes
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A chromosome that is not directly involved in determining sex, as opposed to the sex chromosomes
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Sex chromosomes
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The pair of chromosomes responsible for determining the sex of an individual
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Linked genes
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Genes that are located on the same chromosome and tend to be inherited together in genetic crosses
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