IB Biology Year 1 Semester 2

  1. Define gene
    a portion of a chromosome that determines a trait
  2. Define allele
    a portion of a chromosome that determines a trait
  3. define genome
    the entirety of an organism's hereditary information
  4. genotype
    an organism's genetic makeup
  5. phenotype
    organism's expressed traits
  6. dominant alleles
    allele or trait that dominates over the recessive
  7. recessive alleles
    allele that does not show the trait when it is masked by the dominant
  8. codominant alleles
    alleles that produce a third phenotype when they combine. One allele does not dominant over the other
  9. locus
    location of the gene on the chromosome
  10. homozygous
    having two identical alleles for a trait (PP, pp)
  11. heterozygous
    having two different alleles for a trait (Pp)
  12. carrier
    someone who carries the alleles for a trait but does not express it in their phenotype (one recessive, one dominant)
  13. test cross
    testing a suspected heterozygous by crossing it with a homozygous recessive individual
  14. multiple alleles
    some genes that have more than two alleles
  15. Some genes are present on the ___ chromosome and absent from the shorter ____ chromosome in humans
    X, Y
  16. sex linkage
    traits attaced to the x chromosome and is associated with sexual characteristics
  17. the human female can be _______ or _______ with respect to sexlinked genes

    XB XB XBXb XbXb
    homozygous, heterozygous
  18. Mendel's Law of independent assortment
    each allele pair segregates independently of other allele pairs
  19. Distinguish between autosomes and sex chromosomes
    autosomes are the 1st 22 chromosomes. They are chromosomes that are not associated with sex characteristics. Sex chromosomes are the genes that determine sexual characteristics
  20. linkage group
    a group of different genes whose loci are located on the same chromosome
  21. polygenic inheritance
    having more than one gene that determines a trait
  22. DNA replication is _____
    semi conservative
  23. eukaryotic chromosomes are made of ____ and ____
    DNA and protein
  24. Eukaryotic genes contain _____ and ____-
    introns and exons
  25. DNA replication is initiated at many points in _______ chromosomes
  26. DNA replication occurs in the ________ direction
    5' --> 3'
  27. Transcription is carried out in the ______ direction
    5' --> 3'
  28. Eukaryotic RNA needs the removal of ____ to form mature mRNA
  29. Translation consists of....
    initiation, elongation, translocation, and termination
  30. Translation occurs in the _____ direction
    5'--> 3'
  31. Free ribosomes synthesize proteins for use primarily ________ the cell. Bound ribosomes synthesize proteins for _______ or for ______.
    within, secretion, lysosomes
  32. Nucleosomes help to supercoil ______ and help to regulate _____.
    chromosomes, transcription
  33. In _________, fragments of DNA move in an electric field and are seperated according to size
    gel electrophoresis
  34. Gel electrophoresis of DNA is used in ________.
    DNA profiling
  35. When genes are transferred between species, the amino acid sequence of polypeptides translated from them is ________ because the genetic code is ________.
    unchanged, universal
  36. evolution
    accumulation of changes overtime in the inheritable characteristics of a population. THe change in frequencies of alleles over time
  37. Populations tend to produce more ______ than the environment can support
  38. Members of a species show ______.
  39. Seven levels in the hierarchy of taxa
    Kingdom, Phyla, Class, Order, Family, Genus, Species
  40. Bryophyte
    very small, reproduce by spores, have no true leaves or roots
  41. filicinophyta
    taller, contain true leaves and roots, leaf structure= fronds, reproduce by spores
  42. coniferophyta
    produce cones, seeds develop within the cones, have a wood stem, leaves are in the form of needles or scales
  43. Angiospemophyta
    produce flowers, seeds are within flowers, some may have wood stem, leaves are broad and flat (includes trees)
  44. Porifera
    (sponges) sessile, attach to a substration, no mouth or digestive tract, no organs, simplest of animals
  45. cnidaria
    (corals) have stinging celss called nematocysts, have tentacles, have gastric pouch for digestion, only has one opening
  46. platyhelminthes
    (flat worms) have gut w/ one opening, tend to be flat, Have no heart or lungs
  47. annelid
    (segmented worm) bodies are divided into repeating segments, have a gut with two openings, have a primitive circulatory system which resembles a heart
  48. mollusca
    (snails) many have shells for protections, gut w/ two openings, not divided or segmented
  49. arthropoda
    (insects) hard exoskeleton, has segments (some are fused), have limbs with joints
  50. Bulbs
    vertical underground stem consisting of enlarged bases of leaves (onions)
  51. stem tuber
    horizantal underground growing stems that are modified for food storage (some water) (potato)
  52. storage roots
    modified root tissue that has expanded for the storage of primarily food (carrot)
  53. Tendrils
    modified leaves used to grab on to various things to help support the plant
  54. Dicotyledonous plants have ______ and ______ meristems
    apical and lateral
  55. terrestial plants support themselves by means of _________, ____________, and __________.
    cellulosem cell turgor, and lignified xylem
  56. transpiration
    the evaporation of water from the aerial parts of the plant
  57. Guard cells can open and close stomata to regulate ________.
  58. Plant hormone ________ causes the closing of stomata.
    abscisic acid
  59. species
    a group of organisms that can interbreed and produce fertile offspring
  60. habitat
    an environment in which a species lives
  61. population
    a group of organisms of the same species that live in the same area at the same time
  62. community
    group of populations of different species living and interacting with each other in the same are at the same time
  63. ecosystem
    communtity and its abiotic environment
  64. ecology
    study of the relationships between living organisms and their environment
  65. autotroph
    producer, organisms that make organic molecules from inorganic molecules either using sunlight or chemical energy (ex) plants
  66. heterotrophs
    organisms which need to eat otehr organisms to supply energy and organic molecules (ex) humans
  67. consumer
    an organism that eats other organisms for energy (heterotroph).
  68. detritivore
    a decomposer, ingests dead organic matter and then digests it
  69. Saprotroph
    a decomposer, secreates digestive enzymes to break down dead organic matter outside the body and then absorb it
  70. food chain
    pathway along which food is transferred from trophic level to trophic level, beginning with primary producers
  71. _______ is the initial energy source for almost all communities
  72. Energy transformations are never _______ efficient
  73. _______ can enter and leave an ecosystem, but the ______ must be recycled
    energy, nutrients
  74. Saprotrophic bacteria and fungi recycle ________.
  75. precautionary principle
    even though we are not certain of the effects of something, and there is some evidence or indications as to what the effects might be, we should take action instead of waiting to see the effects
Card Set
IB Biology Year 1 Semester 2
semester exam flash cards