50 DEFINITIONS

  1. Hardy Weinberg Equation
    • p2+2pq+q2=1
    • p=gene frequency of the dominant gene
    • q=gene frequency of the recessive gene
    • p2=percentage of homozygous dominant individuals
    • q2=percentage of homozygous recessive individuals
    • 2pq=percentage of heterozygous individuals

    • It works best for populations where the gene pool stays constant. The criteria are:
    • 1. Large population
    • 2. No mutations occurring within the population
    • 3. Elimination of gene flow so other populations of the
    • same species should be isolated.
    • 4. Random mating within population
    • 5. NO natural selection occurring
  2. Probability
    • The branch of mathematics that predicts the
    • chance that a certain outcome will occur. Probability is used to predict the
    • outcomes of a certain genetic cross.
  3. Conjugation
    Process by which a tube forms between two bacteria and one gives its plasmid to the other. If the receiving bacterium has no plasmid, the donated plasmid stays as is. If there is a plasmid in the receiving bacterium, the two fuse to create a new plasmid.
  4. Transformation
    Process by which unassociated ("naked") pieces of DNA are taken into a bacterium and incorporated into the genome.
  5. Transduction
    Process by which DNA is injected into a bacterium and becomes a part of the bacterium's DNA. This is common with viruses, in which case the bacterium proceeds to make copies of the virus and lyse itself.
  6. Restriction Enzymes
    Bacteria-only enzymes that cuts up foreign DNA, protecting bacteria from DNA of phages and other viruses. Function by locating a specific base sequence in the DNA and cutting there. This, along with gel electrophoresis, enables analysis of genes (such as DNA fingerprinting).
  7. DNA Ligase
    Makes strong covalent bonds between the ends of two molecules after weak hydrogen bonds are set in place. Often used to join sticky-ended DNA strands after the DNA has been cut by restriction enzymes, thus forming recombinant DNA. Also, it is essential for DNA replication.
  8. RFLP
    "Restriction Fragment Length Polymorphisms:" The differences in homologous DNA sequences that are reflected in differing lengths of DNA fragments produced when the DNA is cut by restriction enzymes. This is the idea behind DNA fingerprinting.
  9. PCR
    "Polymerase Chain Reaction:" Technique by which any segment of DNA can be copied quickly and precisely. This allows for small amounts of tissue to be used in DNA fingerprinting. The DNA sample is mixed with loose nucleotide monomers and DNA polymerase. This is first heated to separate the DNA strands then cooled so that the separate DNA strands form complementary strands from the loose nucleotides.
  10. Electrophoresis
    Gel Electrophoresis is a technique used for separating and purifying macromolecules, specifically DNA. The DNA is placed in a solution in wells near the negative end of the gel. The DNA molecules will move towards the positive side because they are negatively charged. The larger DNA fragments do not move as far due to friction. This enables scientists to compare genes using RFLPs.
  11. Transgenic Organisms
    Organisms that contain genes from other species.
  12. Sticky Ends
    Sticky ends are formed when a DNA strand is cut jaggedly by a DNA strand. They allow the DNA strand to be spliced to another DNA strand if the other DNA strand has a sticky end with a complementary sequence to the sticky end of the original. DNA cut by the same restriction enzyme will have complementary sticky ends.
  13. Blunt Ends
    Formed when a DNA strand is cut clean, without any side sticking out. They are not sticky because they are no one-stranded portions of DNA that could be matched up with other sticky ends.
  14. Cloning
    Producing genetically identical copies of a cell, organism, or DNA molecule.
  15. Cytoplasmic Inheritance
    The way in which an animal's mitochondria is solely derived from that of the mother. This is because the middle piece of the sperm, with all of its mitochondria, never actually enters the egg cell.
  16. Karyotyping
    Arranging photos of DNA chromosomes taken during Metaphase into matching pairs to discern any chromosomal abnormalities and to learn the gender of the subject.
  17. Recombinant DNA
    DNA is taken from two different sources and spliced together, using DNA ligase to join the strands where the sticky ends are complementary. The resulting DNA molecule is recombinant.
  18. Plasmid Vectors
    Plasmids contain some of a bacterium's genetic information. Plasmids are sometimes called plasmid vectors due to their ability to transfer the genes they contain from one cell to another.
  19. Bacteriophage
    A virus that inserts its DNA into a bacterium, eventually causing the bacterium to reproduce the virus and lyse.
  20. Prophage
    The DNA of a phage, such as a bacteriophage
  21. Lytic Cycle
    Viral replication cycle resulting in release of new viruses by lysing of the cell.
  22. Lysogenic Cycle
    A type of infection in which a virus embeds its DNA into the host cell's DNA and then is replicated along with the rest of the cell's DNA. After some time, the viral DNA separates from the DNA of all of the cells it has infected and takes the steps a lytic infection would take.
  23. Genetic Drift
    Changes in the gene pool of a population resulting from chance. This is a form of microevolution that has the potential to eliminate certain alleles from small populations by chance.
  24. Founder Effect
    When a new population is established with a different genetic pool than that of its previous population. This form of microevolution often results from migration.
  25. Bottlenecking
    Genetic drift resulting from a vast reduction in population size. This is a form of microevolution.
  26. Gene Flow
    A gene pool that has been altered due to migration of individuals into and out of the gene pool. This is a form of microevolution.
  27. Mutations
    Changes in the nucleotide sequence of DNA that is the ultimate source of genetic diversity. This is a minute form of microevolution.
  28. Natural Selection
    The main factor affecting gene pools, because increased reproductive success leads to increased allele frequency. This cannot be accurately accounted for, and so probability is less useful in predicting trends in the gene pool of populations experiencing this phenomenon.
  29. Macroevolution
    Evolution on a large scale, such as speciation, adaptive radiation (divergent evolution), and extinction.
  30. Microevolution
    Changes in the gene pool of populations over generations.
  31. Coevolution
    Adaptations in one species act as a selective force on a second species, causing the two species to evolve "together."
  32. Punctuated Equilibrium
    Model of evolution in which speciation occurs in short bursts, between which are periods of stability in the gene pool.
  33. Gradualism
    A model of evolution in which evolution occurs constantly, but slowly.
  34. Isolating Mechanisms
    Reproductive characteristics that prevent species from combining.
  35. Prezygotic Barriers
    • These prevent mating & fertilization from occuring. The four are:
    • Temporal
    • Habitat
    • Mechanical
    • Behavioral
    • *Can be remembered by the word THuMB
  36. Temporal Isolation
    Time based prezygotic barrier that states that two species cannot mate because their mating seasons are at different times.
  37. Habitat Isolation
    Although the two species do not live far from one another and might be coitally compatible, they do not mate due to their habitats (ex. garter snakes on land, relatives in water cannot mate)
  38. Behavioral Isolation
    Different species are prezygotically blocked due to different mating behaviors. This can include scents, dances, calls, etc.
  39. Mechanical Isolation
    Male, female sex organs are incompatible; or gametes cannot fuse.
  40. Postzygotic Barriers
    Mechanisms that prevent the results of interspecies mating from being successful, preventing the development of a combined species. Hybrid Inviability and Hybrid Sterility
  41. Hybrid Inviability
    When the offspring dies prior to being able to reproduce, thus preventing the hybrid from being reproductively successful.
  42. Hybrid Sterility
    When the offspring is successful in survival but not in reproduction.
  43. Sexual Selection
    Evolutionary process by which sexually attractive traits become more common in a gene pool. This is separate from natural selection because natural selection selects for survivally attractive traits.
  44. Cline
    A variation in a trait of individuals that coordinates with some gradual change in temperature or other factor
  45. Alliopatric Speciation
    Initial block to a gene flow is a geographic barrier that physically isolates the populations.
  46. Sympatric Speciation
    Origin of a new species without geographic isolation.
  47. Directional Selection
    Individuals at one end of the curve have higher fitness at the middle or other end. As a result, the curve usually moves so that these individuals make up most of the population.
  48. Stabilizing Selection
    Takes place where individuals have higher fitness at the center of the curve compated to the individuals at either end. As a result, the curve becomes steeper.
  49. Disruptive Selection
    Individuals at the upper and lower ends of the curve have higher fitness than individuals in the middle. As a result, two "curves" appear - one for one form of the trait, and another for the opposite, with a "valley" in between the two.
  50. Evidence for Evolution
    • Geographic
    • Embryology
    • Fossil Record
    • Comparative Anatomy
    • Molecular Biology
  51. Homology
    Similarity among body parts that imply a common ancestor.
  52. Analogy
    Similarity of a structure between two unrelated species due to convergent evolution.
  53. Convergent Evolution
    Adaptive change resulting in analogous similarities between organisms. Species of different lineages come to resemble one another as a result of living in similar environments.
  54. Divergent Evolution
    Also referred to as Adaptive Radiation, this is the way in which two species came from a common ancestor yet grew different due to environmental pressures.
  55. Taxonomy
    The branch of biology concerned with identifying, naming, and classifying species
  56. Hierarchy of Classification
    • Domain
    • Kingdom
    • Phylum
    • Class
    • Order
    • Family
    • Genus
    • Species
    • *Dear King Philip Came Over For Good Spaghetti
  57. Species
    A group of organisms that are able to breed together and look very similar.
  58. Spontaneous Generation Theory
    Incorrect notion that life can come from an inanimate material.
  59. Coacervate/Precell
    Formed as a result of protein ionizing and attracting polar water. Were not able to replicate themselves, but could store and pass on nucleic acids.
  60. Reducing atmosphere
    Atmoshpere of the early Earth, which had no free oxygen.
  61. Urey-Miller Experiment
    Complex experiment that proved that Earth's early atmosphere could have produced organic compounds as a result of lightning.
  62. Heterotroph Hypothesis
    Hypothesis that states that life could have resulted without a "divine nudge" or existence of life on other planets. The organic components formed as a result of lightning (acting upon the early atmosphere) and arranged themselves into units that would later be the source of life.
  63. CREDIT FOR DEFINITIONS GOES TO LUKE
Author
Jeffreeze
ID
74537
Card Set
50 DEFINITIONS
Description
50 DEFINITIONS FOR THE BIO TEST
Updated