Modern Biology Final Study Guide – Flashcards

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Genetics
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the field of biology devoted to understanding how characteristics are transmitted from parents to offspring
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Heredity
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the transmission of characteristics from parents to offspring
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Trait
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a genetically determined variant of a characteristic
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Pollination
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a process that occurs when pollen grains produced in the male reproductive parts of a flower, called the anthers, are transferred to the female reproductive part of a flower, called the stigma
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Self-Pollination
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a process that occurs when pollen is transferred from the anthers of a flower to the stigma of either that flower or another flower on the same plant
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Cross-Pollination
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a process that occurs between flowers of two plants
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True-Breeding
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plants that are pure for a trait that always produce offspring with that trait when they self-pollinate
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P Generation
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the true-breeding parents
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F1 Generation
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the first filial generation; offspring of the P generation
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F2 Generation
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the second filial genration
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Dominant
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a factor that masked, or dominated, the factor for the other trait in the pair
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Recessive
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the factor that controlled the trait that did not apear in the F1 generation but reappeared in the F2 generation
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Law of Segregation
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states that a pair of factors is segregated, or separated, during the formation of gametes
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Law of Independent Assortment
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states that factors separated independently of one another during the formation of gametes
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Molecular Genetics
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the study of the structure and function of chromosomes and genes
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Allele
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Each of two or more alternative forms of a gene
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Genotype
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an organism's genetic makeup
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Phenotype
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an organism's appearance
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Homozygous
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the organism is said to be this when both alleles of a pair are alike
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Heterozygous
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the organism is said to be this when both alleles of a pair are different
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Probability
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the likelihood that a specific event will occur
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Monohybrid Cross
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a cross in which only one characteristic is tracked
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Punnett Square
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a diagram scientists use to aid them in predicting the probable distribution of inherited traits in the offspring
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Genotypic Ratio
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the ratio of the genotypes that appear in offspring
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Phenotypic Ratio
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the ratio of the offspring's phenotypes
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Testcross
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a cross in which an individual of unknown genotype is crossed with a homozygous recessive individual
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Complete Dominance
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a relationship in which one allele is completely dominant over another
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Incomplete Dominance
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a relationship in which the F1 offspring will have a phenotype in between that of the parents
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Codominance
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a relationship that occurs when both alleles for a gene are expressed in a heterozygous offspring
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Dihybrid Cross
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a cross in which two characteristics are tracked
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Chromosomes
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Rod-shaped structures made of DNA and proteins.
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Histones
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Maintain the shape of chromosomes and aid in the tight packing of DNA.
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chromatid
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Each half of the chromosomes.
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Centromere
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The point where two Chromatids are attached.
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Chromatin
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Less tightly coiled DNA-protein complex.
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Sex Chromosomes
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Determine the sex of the organism.
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Autosomes
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All the other chromosomes in the organism.
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Homologous Chromosomes
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Two copies of each Autosomes.
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Karyotype
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A photomicrograph of the chromosomes in a normal dividing cell found in a human.
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Diploid
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Two sets of chromosomes. Body Cells.
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Haploid
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Sperm Cells and Egg Cells.
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Binary Fission
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The division of a prokaryotic cell into two offspring cells.
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Mitosis
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Cell division that results in new cells.
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Asexual Reproduction
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Is the production of offspring from one parent.
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Meiosis
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Reduces the chromosome count by half in new cells.
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Gametes
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Haploid reproiductive cells.
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Interphase
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The time between cell division. (The Phase)
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Cytokinesis
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The division of the cells cytoplasm.
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Prophase
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The first phase of Mitosis.
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Spindle Fiber
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Radiate from the newly seperated centromeres to prepare for Metaphase.
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Metaphase
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The second phase of Mitosis, chromosomes are larger in this phase.
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Anaphase
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The third phase, chromatids of each chromosome seperate at the centromere and slowly move away from eachother.
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Telophase
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After the chromosome seperates, the cell seals off, Final Phase of Mitosis.
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Cell Plate
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In a plant cell, midline of dividing cells. Becomes the cell wall eventually.
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Synapsis
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The pairing of Homologous Chromosomes.
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Tetrad
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Each pair of Homologous Chromosomes.
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Crossing-over
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Chromotids may break off and connect to adjacent Homologous Chromosomes.
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Genetic Recombination
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A new mixture of genetic material is created.
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Independant Assortment
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The random seperation of the Homologous Chromosomes.
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Spermatogensis
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The production of sperm cells.
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Oogenesis
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The production of mature egg cells.
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Polar Body
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The other three products of meiosis that eventually degenerate.
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Sexual Reproduction
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The production of offspring through meiosis and the union of a sperm and an egg cell.
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sex chromosome
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one of the pair of chromosomes that determine the sex of an individual
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autosome
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any chromosome that is not a sex chromosome
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sex-linked trait
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a trait that is determined by a gene found on one of the sex chromosomes, such as the X chromosome or the Y chromosome in humans
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linked gene
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one of a pair of genes that tend to be inherited together
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chromosome map
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a diagram of gene positions on a chromosome
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map unit
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in chromosome mapping, an increment of 1 percent in the frequency of crossing-over
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germ-cell mutation
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mutation that occurs in an organism's gametes
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somatic-cell mutation
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a mutation that occurs in a body cell
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lethal mutation
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a gene or chromosomal mutation that influences the development of an organism in such a way that the organism cannot survive
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deletion
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the loss of a part of DNA from a chromosome
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inversion
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a reversal in the order of the genes, or of a chromosome segment, within a chromosome
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translocation
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the movement of a segment of DNA from one chromosome to another, which results in a change in the position of the segment; also the movement of soluble nutrients from one part of a plant to another
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nondisjunction
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the failure of homologous chromosomes to separate during meiosis I or the failure of sister chromatids to separate during mitosis or meiosis II
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point mutation
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a mutation in which only one nucleotide or nitrogenous base in a gene is changed
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substitution
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a mutation in which one nucleotide is replaced by another nucleotide
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frameshift mutation
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a mutation, such as the insertion or deletion of a nucleotide in a coding sequence, that results in the misreading of the code during translation because of a change in the reading frame
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insertion mutation
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a mutation in which one or more nucleotides are added to a gene
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pedigree
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a diagram that shows the occurrence of a genetic trait in several generations of a family
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carrier
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in biology, an individual who has one copy of a recessive autosomal allele that causes disease in the homozygous condition
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genetic disorder
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an inherited disease or disorder that is caused by a mutation in a gene or by a chromosomal defect
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polygenic
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describes a characteristic that is influenced by many genes
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complex character
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a character such as skin color that is influenced strongly by both genes and the environment
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multiple alleles
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more than two alleles (versions of the gene) for a genetic trait
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codominance
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a condition in which both alleles for a gene are fully expressed
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incomplete dominance
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a condition in which a trait in an individual is intermediate between the phenotype of the individual's two parents because the dominant allele is unable to express itself fully
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sex-influenced genes
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an autosomal trait that is influenced by the presence of male or female sex hormones
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Huntington's disease
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an autosomal dominant condition characterized by forgetfulness and irritability
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amniocentesis
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a procedure used in fetal diagnosis in which amniotic fluid is removed from the uterus of the pregnant woman
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chorionic villi sampling
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a procedure in which the chorionic villi to are analyzed to diagnose fetal genotypes
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genetic counseling
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the process of testing and informing potential parents about their genetic makeup and the likelihood that they will have offspring with genetic defects or hereditary diseases
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gene therapy
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a technique that places a gene into a cell to correct a hereditary disease or to improve the genome
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virulent
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describes a microorganism that causes disease and that is highly infectious; strictly, refers only to viruses that reproduce from the lytic cycle
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transformation
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the transfer of genetic material in the form of DNA fragments from one cell to another or from one organism to another
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bacteriophage
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a virus that infects bacteria
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nucleotide
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in a nucleic-acid chain, a subunit that consists of a sugar, a phosphate, and a nitrogenous base
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deoxyribose
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a five-carbon sugar that is a component of DNA molecules
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nitrogenous base
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an organic base that contains nitrogen, such as a purine or pyrimidline; a subunit of a nucleotide in DNA and RNA
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purine
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a nitrogenous base that has a double-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; either adenine or guanine
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pyrimidine
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a nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; thymine, cytosine, or uracil
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base pairing rules
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the rules stating that cytosine pairs with guanine and adenine pairs with thymine in DNA, and adenine pairs with uracil in RNA
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complementary base pair
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the nucleotide bases in one strand of DNA or RNA that are paired with those of another strand
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base sequence
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the order of the nitrogenous bases on a chain of DNA
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DNA replication
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the process of makinf a copy of DNA
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helicase
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an enzyme that separates DNA strands
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replication fork
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a Y-shaped point that results when the two strandes of a DNA double helix separate so that the DNA molecule can be replicated
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DNA polymerase
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an enzyme that catalyzes the formation of the DNA molecule
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semi-conservatice replication
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in each new DNA double helix, one strand is from the original molecule,and one strand is new
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mutation
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a change in the nucleotide-base sequence of a gene or DNA molecule
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RNA
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a natrual polymer that is present in all living cells and that plays a role in protein synthesis
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transcription
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the process of forming a nucleic acid by using another molecule as a template; particulary the process of synthesizing RNA by using one strand of a DNA molecule as a template
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translation
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the portion of protein synthesis that takes place at ribosomes and that uses the codons on mRNA molecules to specify the sequence of amino acids in polypeptide chains
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protein synthesis
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the formation of proteins by using information contained in DNA and carried by mRNA
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ribose
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a five-carbon sugar present in RNA
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mRNA (messenger RNA)
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a single-stranded RNA molecule that encodes the information to make a protein
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tRNA (transfer RNA)
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an RNA molecule that transfers amino acids to the growing end of a polypeptide chain during translation
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RNA polymerase
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an enzyme that starts (catalyzes) the formation of RNA by using a strand of a DNA molecule as a template
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promoter
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a nucleotide sequence on a DNA molecule to which an RNA polymerase molecule binds, which initiates the transcription of a specific gene
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termination signal
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a specific sequence of nucleotides that marks the end of a gene
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genetic code
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the rule that describes how a sequence of nucleotides, read in groups of three consecutive nucleotides (triplets) that correspond to specific amino acids, specifies the amino acid sequence of a protein
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codon
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in DNA, a three-nucleotide sequence that encodes an amino acid or signifies a start signal or a stop signal
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anticodon
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a region of tRNA that consistsof three bases complementary to the codon of mRNA
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genome
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the complete genetic material contained in an individual
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rRNA (ribosomal RNA)
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an organelle that contains most of the RNA in the cell and that is responsible for ribosome function
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biogenesis
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the theory that living organisms come only from other living organisms
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spontaneous generation
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an early and now disproved theory that living organisms come to life spontaneously from nonliving material
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radiometric dating
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a method of determining the absolute age of an object by comparing the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope
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isotope
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an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
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mass number
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the sum of the numbers of protons and neutrons in the nucleus of an atom
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radioactive decay
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the disintegration of an unstable atomic nucleus into one or more different nuclides, accompanied by the emission of radiation, the nuclear capture or ejection of electrons, or fission
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radioactive isotope
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an isotope that has an unstable nucleus and that emits radiation
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half-life
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the time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope
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microsphere
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a microscopic spherical structure composed of many protein molecules that are organized as a membrane
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coacervate
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a mass of colloidal substances held together by electrostatic attraction
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ribozyme
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a type of RNA that can act as an enzyme
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archaea
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prokaryotes (most of which are known to live in extreme environments) that are distinguished from other prokaryotes by differences in their genetics and in the makeup of their cell wall;
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chemosynthesis
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the production of carbohydrates through the use of energy from inorganic molecules instead of light
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ozone
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a gas molecule that is made up of three oxygen atoms
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endosymbiosis
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a mutually beneficial relationship in which one organism lives within another
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cyanobacteria
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a group of photosynthetic, unicellular prokaryotes
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absolute age
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the actual age in years of a fossil
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acquired trait
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a trait not determined by genes but arising as a result of experience or behavior
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adapt
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in populations, to change genetically over generations to become more suited to the environment
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adaptation
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an inherited trait that increases an organism's chance of survival in a particular environment
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adaptive advantage
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a favorable trait in an organism
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adaptive radiation
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an evolutionary pattern in which many species evolve from a single ancestral species
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analogous structure
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in evolution, structures in more than one organism that have similar appearance and function but different embryological origins
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artificial selection
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breeding of organisms by humans for specific phenotypic characteristics
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biogeography
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study of the geographical distribution of fossils and living organisms
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cast
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a type of fossil formed when sediments fill in the cavity left by a decomposing organism
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coevolution
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the mutual evolution of two different species interacting with each other
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conserve
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the act of preserving genes that remain unchanged in DNA
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convergent evolution
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the process by which unrelated species become more similar as they adapt to the same kind of environment
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divergent evolution
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the process of two or more related species becoming more and more dissimilar
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extinction
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the dying out of a species
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fitness
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a measurement of the ability of a species to respond to the pressures of natural selection; the ability of individuals to survive to propagate their genes
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fossil
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the remains or traces of a once-living organism
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homologous
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features similar features that originated in a shared ancestor
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law of superposition
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a law that states that successive layers of rock or soil were deposited on top of one another and the lowest level is oldest
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mass extinction
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one of the brief periods of time during which large numbers of species disappeared
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mold
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a type of fossil formed from an impression of the shape or tracks of an organism; in fungi, a mass of tangled filaments of cells, such as the fungus that grows on bread
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natural selection
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the process by which organisms with favorable variations reproduce at higher rates than those without such variations
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population
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all the members of a species that live in the same area and make up a breeding group
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relative age
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the comparative ages of fossils found within a single stratum
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sediment
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dust, sand, or mud deposited over time by wind or water
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stratum
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in geology, a layer of soil or rock in a cross section of the Earth
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uniformitarianism
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a principle that states that the geological structure of Earth resulted from cycles of observable processes and that these processes operate continuously
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vestigial
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referring to a functionless structure that was functional in an ancestral species
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biodiversity
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the variety of organisms considered at all levels from populations to ecosystems
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taxonomy
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the science of describing, naming, and classifying organisms
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taxon
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any particular group within a taxonomic system
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kingdom
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in a traditional taxonomic system, the highest taxonomic category, which contains a group of similar phyla
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domains
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categories above the kingdom level
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phyla (singular,phylum)
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Subsets below the kingdom level.
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classes
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category contained within a phylum or division and containing orders
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orders
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the category contained within a class and containing families.
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family
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In a traditional taxonomic system, the category contained within an order and containing genera.
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genus
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In a traditional taxonomic system, the category contained within a family and containing species
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species
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the smallest grouping, which contains only a single kind of organism
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binomial momenclature
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system of two-part names
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subspecies
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variations of a species that live in different geographic areas
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systematics
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the classification of living organisms in terms of their natural relationships; it includes describing, naming, and classifying the organisms
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phylogenetics
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the analysis of evolutionary, or ancestral, relationships between taxa
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phylogenetic diagram
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a branching diagram that models the relationships by ancestry between different species or other taxonomic groups
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cladistics
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a phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxa
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shared character
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A feature that is shared by all members of a particular group of organisms
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derived character
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A feature that evolved only within a particular taxonomic group
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clade
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A taxonomic grouping that includes only a single ancestor and all of its descendants
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cladograms
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A diagram that is based on patterns of shared, derived traits and that shows the evolutionary relationships between groups of organisms.
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bacteria
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in a modern taxonomic system, a domain made up of prokaryotes that usually have a cell wall and that usually reproduce by cell division; this domain aligns with the traditional kingdom Eubacteria
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archaea
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in a modern taxonomic system, a domain made up of prokaryotes that can live in extreme environments and that are differentiated from other prokaryotes by various important chemical differences; this domain aligns with the traditional kingdom Archaebacteria.
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eukarya
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domain which consists of eukaryotic organisms. Cells of organisms ar large and have a true nucleus and complex cellular organelles. Domain eukarya includes plants, animals, fungi
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eubactria (true bacteria)
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aligns with domain Bacteria. Names means true bacteria
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archaebacteria (ancient bacteria)
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aligns with domain Archaea. Name means ancient bacteria
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protista
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Kingdom composed of eukaryotes that are not classified as plants, animals, or fungi
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fungi
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a classification kingdom made up of nongreen, eukaryotic organisms that get food by breaking down organic matter and absorbing the nutrients, reproduce by means of spores, and have no means of movement
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plantae
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a classification kingdom made up of eukaryotic, multicellular organisms that have cell walls made mostly of cellulose, that have pigments that absorb light, and that supply energy and oxygen to themselves and to other life-forms through photosynthesis
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animalia
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the classification kingdom containing complex, multicellular organisms that lack cell walls, are usually able to move around, and possess specialized sense organs that help them quickly respond to their environment
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