Exam 1 Flashcards.txt

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Exam 1 Flashcards.txt
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Bio115 Exam1
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  1. Prokaryote
    lack nuclear membrane and possess no membrane-bound organelles
  2. Eukaryotes
    Have a nuclear membrane and membrane-bound organeles
  3. What is the fundamental unit of heredity?
    the gene
  4. Principle of segregation
    Diploid's alleles separate in equal proportions
  5. What is a testcross?
    Crossing an individual of unknown genotype with a homozygous recessive individual to reveal the unknown.
  6. When a het has a phenotype intermediate between the phenotypes of two homo, the trait is said to be _______
    incomplete dominance
  7. When two alleles separate, their separation is independent of the separation of alleles at other loci. What principle is this?
    Independent assortment
  8. What kind of crosses reveal the principle of independent assortment?
    Dihybrid
  9. How do you determine the chi-square value for inheritance of crosses?
    chi-square = sum((obs_i - exp_i)/exp_i), with degrees of freedom one less than the expected number of phenotypes
  10. What type of sex determination has males with only one X?
    XX-XO sex determination
  11. What type of sex determination has males with two of the same chromosome?
    ZZ-ZW sex determination
  12. What determines phenotype in Drosophila?
    X:A ratio, A is number of autosomes
  13. In humans, what does the combination of XO chromosomes lead to?
    Turner's syndrome
  14. In humans, what does the combination of XXY chromosomes lead to?
    Klinefelter syndrome
  15. In humans, what does the combination of XXX chromosomes lead to?
    Poly-X females
  16. What is a reciprocal cross?
    It is a breeding experiment designed to test the role of parental sex on a given inheritance pattern. In one cross, a male expressing the trait of interest will be crossed with a female not expressing the trait. In the other, a female expressing the trait of interest will be crossed with a male not expressing the trait.
  17. If only one copy of a chromosomal region is present, such as X-linked genes in humans, this is called ______
    Hemizygous
  18. __________ equalizes the amount of protein produced by X-linked genes in the two sexes.
    Dosage compensation
  19. What is the Lyon hypothesis?
    Darkly staining bodies in the nuclei of female cats (known as Barr bodies) were inactive X chromosomes
  20. _______ is when the phenotype of the het is intermediate between the two homozygotes
    Incomplete dominance
  21. The MN blood group is an example of _________.
    Codominance
  22. __________ is the percentage of individuals with a particular genotype that express the expected phenotype.
    Penetrance
  23. _______ describes the degree to which a genotype is phenotypically expressed.
    Expressivity
  24. A ____________ causes death at an early stage of development, often before birth
    lethal allele. Note that this affects the phenotypic ratio outcome
  25. An allele is said to be ______ when it has more than one phenotype.
    pleiotropic
  26. _______ occurs when genes at multiple loci affect a single phenotype.
    Gene interaction
  27. The mallard example with duck feather pattern highlighted _________
    multiple alleles at a single locus.
  28. ______ is a phenomenon in which a one gene masks (hides) the effect of another gene at a different locus
    Epistasis
  29. The gene that does the masking is called the _______
    epistatic gene
  30. The gene that is masked is called the ______ gene.
    hypostatic
  31. The presence of either of two recessive alleles at two different loci resulting in a recessive phenotype is called ______
    duplicate recessive epistasis
  32. When a single copy of an allele is sufficient to mask the phenotype of alleles at a second locus, this is ______
    dominant epistasis
  33. Interpreting dihybrid cross ratios is often easier if the amount is ...
    multiplied by 16 and then divided by the total
  34. ______ traits are present in males and females, but are inherited only from the mother and can result in phenotypic variation.
    Cytoplasmically inherited
  35. __________ is a phenomenon in which the phenotype of the offspring is determined by the genotype of the mother.
    Genetic maternal effect. Note that the offspring's phenotype is determined by mother's genotype, not her phenotype.
  36. _________ is the differential expression of genetic material depending on whether it is inherited from the male of female parent.
    Genomic imprinting
  37. At the ______________, the mutant protein functions normally.
    permissive temperature
  38. At the ____________, mutant protein is inactivated and endocytosis is halted, resulting in paralysis.
    non-permissive temperature
  39. Characteristics that have a few easily distinguished characteristics, such as seed color or shape, are called _____.
    discontinuous characteristics
  40. _________ are characteristics, such as height, for which a continuous distribution of phenotypes is observed. Also called _________.
    Continuous characteristics, quantitative characteristics
  41. Continuous characteristics frequently arise because genes at many loci interact to produce the phenotype: ________.
    polygenic characteristics
  42. What is the number of genotypes encoded by n loci with two alleles?
    3^n
  43. Name useful characteristics of genetic model organisms.
    • short generation time
    • large number of progeny
    • adaptable to lab environment
    • housed and propagated relatively inexpensively
    • genomes sequenced
  44. What model organism has a homolog whose mutant in a human eye disease?
    Drosophila melanogaster
  45. What model organism taught us about differences in skin color?
    Zebrafish (Danio rerio)
  46. What is the most widely studied prokaryote?
    Escherichia coli, regulation of expression of genes
  47. What is the simplest eukaryotic genetic model organism?
    Baker's yeast (Saccharomyces cerevisiae), DNA damage/repair
  48. What is the most basic multicellular animal that is a genetic model organism?
    roundworm (Caenorhabditis elegans), neurotransmitters
  49. What is the mammalian genetic model organism?
    House mouse (Mus musculus), white blood cells
  50. What is the primary plant model organism?
    Thale cress plant (Arabidopsis thaliana); genome structure, plant evolution
  51. _______, the person from whom the pedigree is initiated.
    Proband
  52. Characteristics of autosomal recessive traits in pedigrees
    • Normal parents have affected children
    • Equal number of males and females
    • 1/4 of offspring of two carriers are affected
    • Normal children with affected siblings have a 2/3 chance of being a carrier
    • Consanguineous marriages are sometimes involved
    • Example: tay-sachs
  53. Characteristics of autosomal dominant traits in pedigrees
    • Does not skip generations (unless incompletely penetrant/express)
    • Approx equal number males and females
    • Most affected individuals are heterozygous
    • 1/2 offspring of an affected individual are affected
    • These alleles tend to be very rare, even more so for homozygous
    • Example: elevated blood cholesterol
  54. Characteristics of X-linked recessive traits in pedigrees
    • Males usually affected
    • Usual transmission from carrier woman to son
    • Daughters of carrier mothers have 1/2 chance of being carriers
    • Not passed from father to son
    • Affected woman must have an affected father and either an affected mother or carrier mother
    • Example: Hemophilia A
  55. Characteristics of X-linked dominant traits in pedigrees
    • Affected males only have affected daughters.
    • Affected mothers have 1/2 affected kids, and 1/2 normal
    • Trait does not skip generations
    • Rare: assume heterozygous
    • Example: Hypophosphatemia - vitamin D resistant rickets
  56. Characteristics of Y-linked traits in pedigrees
    • Very rare
    • Father to son transmissions
    • All male offspring are affected
  57. ______ genes do not assort indepently.
    Linked
  58. ______ is the soring of alleles into new combinations
    Recombination
  59. Genes on the same chromosome belong to the same ________
    linkage group
  60. If the genes of interest are linked, only _______ progeny are produced.
    nonrecombinant
  61. Genes that exhibit crossing over are ________.
    incompletely linked
  62. A single crossover produces what ratio of recombinant to nonrecombinant gametes?
    half
  63. _____ is the percentage of progeny produced in a cross.
    Recombination frequency
  64. Wild-type alleles in a _____ configuration are on the same chromosome.
    coupling
  65. Wild-type alleles in a _____ configuration are on different chromosomes.
    repulsion
  66. What are the two types of recombination?
    Interchromosomal and intrachromosomal.
  67. Which type of recombination arises from independent assortment?
    interchromosomal
  68. Who discovered that Intrachromosomal Recombination Results from Physical Exchange Between Chromosomes?
    Harriet Creighton and Barbara McClintock
  69. ______ are chromosome maps calculated by using the genetic phenomenon of recombination.
    Genetic maps, 1 m.u. = 1% recombination
  70. ______ are chromosome maps calculated by using physical distances along the chromosome.
    Physical maps, distance in base pairs
  71. Why are genetic maps based on short distances more accurate than those based on long distances?
    Double crossovers are not detected
  72. In a 3-point cross, classes with the fewest progeny are ____.
    double-crossovers
  73. In a 3-point cross, classes with the most progeny are ____.
    nonrecombinants
  74. In a 3-point cross, the recombination frequency is calculated by adding all the crossovers (single and double) between two genes and dividing by the total number of progeny.
    See example Lecture 10, Slide 7
  75. The degree to which one crossover interferes with additional crossovers in the same region is termed ________.
    interference
  76. The ratio of observed double crossovers to expected double crossovers is called the _______.
    coefficient of coincidence
  77. The number of expected double crossovers can be calculated by multiplying the total number of progeny by _____.
    the product of the probability of recombination for the single crossovers.
  78. Interference =
    1- coefficient of coincidence
  79. Disease causing genes are mapped by _______ analysis which examines the probability of having linkage at a particular RF compared to the probability of independent assortment.
    logarithm of odds
  80. A LOD score of 3 indicates linkage with the specified recombination is _____ times as likely to produce what was observed as independent assortment.
    1000
  81. Variable genes with easily observable phenotypes are called ____.
    genetic markers
  82. Variations in in DNA sequence detected by cutting the DNA with restriction enzymes are called _____.
    Restriction Fragment Length Polymorphisms (RFLPs)
  83. Variable numbers of short DNA sequences repeated in tandem are called ____.
    microsatellites
  84. Individual variations in the DNA nucleotides are called ____.
    Single Nucleotide Polymorphisms (SNPs)
  85. Describe deletion mapping.
    • Individual homozygous for a recessive mutation in the gene of interest is crossed with an individual heterozygous for a deletion.
    • If the gene of interest is in the deletion region, half of the progeny will dislay the mutant phenotype.
    • If it's not, all the progeny will be wild type.
  86. Describe somatic-cell hybridization
    See first 3 slides of Lecture 11. It's used for gene mapping
  87. _____ is a method for determining the chromosomal location of a particular gene through molecular analysis.
    in situ hybridization
  88. Wild-type bacteria are called ____.
    prototrophic
  89. _____ contains all the nutrients required by prototrophic bacteria.
    Minimal media
  90. Mutant strains called _____ lack enzymes necessary for metabolizing nutrients or synthesizing essential molecules.
    auxotrophs
  91. _____ contains all substances required by bacteria for growth and reproduction.
    Complete media
  92. Most bacteria have __#__ _____ (shape) chromosome(s) several million base pairs long.
    1, circular
  93. Many bacteria also contain small (several thousand base pairs), circular DNA molecules called ____.
    plasmids
  94. _____ are plasmids capable of freely replicating and able to integrate into the bacterial chromosome.
    Episomes
  95. The ______ in E. coli controls mating and gene exchange between E. coli cells.
    F (fertility) factor
  96. Plasmids Replicate _____ of the Bacterial Chromosome.
    Independently
  97. What are three types of gene transfer in bacteria?
    Conjugation, transformation, and transduction
  98. In ______, a cytoplasmic bridge forms allowing transfer of part of DNA from one bacteria to another.
    conjugation
  99. In _____, naked DNA is tken up by the recipient cell/bacteria.
    transformation
  100. In ______, a virus attaches to a bacteria cell to inject DNA.
    transduction
  101. _____ is usually the only DNA transferred during conjugation.
    F factor
  102. Conjugation between an F+ cell with an F- cell results in an ____ cell.
    F+
  103. ____ cells contain an F factor integrated into the bacterial genome.
    Hfr (high frequency)
  104. Bacterial genes can be transferred from an ___ cell to an F- cell in conjugation.
    Hfr
  105. An Hfr cell can be converted into an F' cell during ______.
    sexduction
  106. Sexduction produces _______, cells with two copies of some genes.
    merozygotes (partial diploids)
  107. The transfer times of genes between bacteria indicate the order and relative distances which can be used to construct a ______.
    genetic map
  108. _______ are small circular plasmids that carry genes that encode antibiotic resistance and can be transferred by conjugation.
    R plasmids

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