Human Genetics

Card Set Information

Author:
bbeckers88
ID:
108745
Filename:
Human Genetics
Updated:
2011-10-13 14:58:12
Tags:
Human Genetics Test
Folders:

Description:
questions for test 1
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user bbeckers88 on FreezingBlue Flashcards. What would you like to do?


  1. Chromosome
    2 tightly wound pieces of DNA
  2. how many chromosomes do humans have
    23 pair/46 total
  3. chromatid
    2 found in each chromosome (humans have 92)
  4. centromere
    a protein that holds the 2 chromatids together
  5. diploid
    • having 2 of each chromosome/cell
    • humans
  6. homologus pairs
    • identical
    • humans have a maternal homolog and a paternal homolog
  7. autosomes
    • non-sex chromosomes
    • 22 pair
  8. sex chromosomes
    1 pair determining sex
  9. 3 ways to identify chromosomes
    • 1) size
    • 2) centromere location
    • 3) staining
  10. metacentric
    centromere is located int he middle
  11. submetacentric
    centromere is located a little off center
  12. acrocentric
    centromere is located at the end/tip
  13. chromosome satellites
    • found on acrocentric chromosomes
    • a bulge of DNA on the tip of the chromatid
    • forms part of the nucleus
  14. staining uses:
    banding patters
  15. denver system
    • chromosomes grouped into 7 categories based on size and centromere location
    • displayed as a karyotype
    • possible to identify changes in chromosome # and major changes in structure
  16. Paris conference system
    • identifies chromosome by unique banding pattern
    • possible to see fairly small deletions, additions, or re-arranements of chromosomes
  17. international system of human chromosome nomenclature
    • each chromosome is #ed
    • identified by idiogram
    • chromosome ends are named p and q
    • banding regions are numbered away from the centromere (subdivided into bands)
  18. why is the international system of human chromosome nomenclature useful?
    reveals major and minor deletions, duplications and larger re-arrangements (inversions) and translocations
  19. how is a specific location named using the international system of human chromosome nomenclature?
    list # of chromosomes, sex chromosomes, chromosome #, arm, region, and band
  20. idiogram
    banding patterns of a chromosome
  21. are banding patterns genes??
    NO!
  22. euploidy
    having a complete set of chromosomes
  23. haploidy
    having one complete set of chromosomes (23)
  24. diploidy
    having 2 complete sets of chromosomes (46)
  25. aneuploidy
    1 missing/additional chromosome
  26. monosomy
    • type of aneuploidy
    • missing 1 chromosome
    • 2N-1
    • all considered non-viable
  27. Trisomy
    • type of aneuploidy
    • 1 extra chromosome
    • 2N+1
  28. Patau's syndrome
    trisomy 13
  29. Edwards syndrome
    Trisomy 18
  30. Down's syndrome
    Trisomy 21
  31. what is the karyotype abbreviation for Down's?
    47,XX,+21
  32. what is the live birth incidence of downs?
    1 in 800
  33. what are the distinct features of Down's
    • oblique palpebral fissures with epicanthic folds
    • hypotonia
    • mental retardation
  34. what accounts for 1/3 of moderate/severe mental retardation in kids?
    down's syndrome
  35. most common way to diagnose downs?
    translucency of nuchal area on ultrasound
  36. is there a recurrent risk for women who are under 40?
    yes, about 1%
  37. what causes an aneuploidy?
    failures during meitotic separation (non-dysjunction during anaphase 1 and 2)
  38. deletions
    • partial monosomy
    • a piece of the chromosome is removed
  39. prader-Willi syndrome
    deletion on paternal chromosome 15
  40. Angelman syndrome
    deletion on maternal chromosome 15
  41. Cri Du Chat
    deletion on chromosome 5
  42. duplication
    • partial trisomy
    • part of a chromosome is repeated
  43. inversion
    a piece of a chromosome is flipped around
  44. translocation
    two chromosomes break and exchange pieces
  45. translocation Down's
    • 5% of Down's cases
    • exchange b/t chromosomes 21 and 14
  46. what would be the outcome from 1 normal parent and 1 translocation downs carrier??
    • 25% normal offspring
    • 25% translocation Down's carriers
    • 25% monosomy 21 (non-viable)
    • 25% translocation Down's
  47. Chronic Myelogenous leukemia
    translocation (9;22)
  48. frequency of live births with a chromosomal abnormality?
    1 in 200
  49. miscarriage=
    spontaneous abortion
  50. what % of recognizable pregnancies abort?
    15% (up to 50%)
  51. what % of abortions are of normal fetuses?
    about 50%
  52. are chromosomal defects common?
    yes
  53. how do you measure chromosomal disease rate?
    pregnancy rate- miscarrage (so if all abnormalities are miscarried...no disease rate!)
  54. what are repeated miscarrages suggestive of?
    a chromosomal problem with one or both parents
  55. steps of meiosis
    • interphase
    • prophase
    • metaphase
    • anaphase
    • telophase (repeat last 4 twice for meiosis 2)
  56. Pre-meiotic interphase
    • s-phase
    • chromatin visable- DNA doubles
  57. prophase 1
    • chromosomes appear and condense
    • pairs align and crossing-over occurs
  58. metaphase 1
    • pairs line up and attach to spindle apparatus
    • random assortment occurs
  59. Anaphase 1
    dysjunction occurs- separation of homologous pairs (non-dysjunction could also occur)
  60. Telophase 1
    nucleus reforms, cytoplasm separates (cytokenesis)
  61. non-dysjunction
    if pairs of chromosomes/chromotids dont separate (how trisomy 21 occurs)
  62. Prophase 2
    recoiling of chromosomes
  63. metaphase 2
    chromosomes line up and attach to spindle apparatus
  64. anaphase 2
    spearation of chromatids (dysjunction)
  65. telophase 2
    reconstruction, chromatids uncoil to chatin
  66. post-meitotic interphase
    4 haploid daughter cells are made from 1 parent cell
  67. meiosis
    gametic cell division
  68. what important thing occur during meiosis?
    • formation fo gametes
    • reduction of chromosome number
    • random assortment
    • crossing over
  69. main part of meiosis 1?
    separating of pairs of chromosomes
  70. main part of meiosis 2?
    separating of chromatids
  71. meiosis is critical for?
    • chromosomal basis of sexual reproduction
    • patterns of inheritance
    • generating diversity
    • chromosomal defects
  72. Genes:
    • are a nucleotide coding sequence for a protein, molecular component or trait
    • they are the smallest unit of biological instruction
  73. genome
    the entire genetic constitution of humans
  74. how many genes are in the human genome?
    25,000 (99% are non-coding)
  75. gene locus
    the location of a given gene on a chromosome
  76. Allele
    different forms of a gene
  77. polymorphic genes
    alleles with signicicant variation
  78. conserved genes
    alleles which are very similar
  79. mutation:
    the process of nucleotide change (how alleles are made)
  80. wild-type alleles
    the most common form, produces expected outcome, dominant
  81. mutant alleles
    the variant form, doesnt produce normal outcome, recessive
  82. point mutations
    • small, 1 or 2 changes
    • may or may not cause a change in the final peptide
  83. 2 reasons a point mutation would not have an effect?
    • the genetic code is degenerative
    • a change in a non-coding segment doesnt matter
  84. Genotype
    the pair of genes a person has
  85. AA genotype
    homozygous dominant
  86. Aa genotype
    heterozygous
  87. aa genotype
    homozygous recessive
  88. phenotype
    the outward expression of a persons genotype
  89. AA phenotype
    normal/expected
  90. Aa phenotype
    normal/expected
  91. aa phenotype
    recessive trait
  92. phenotype =
    genotype + environment
  93. incomplete dominance
    in heterozygote, neither allele is fully expressed, you get a combination (red + white = pink)
  94. simple disease
    caused by a single gene mutation
  95. simple genetics
    involve the inheritance of traits that follow predictable patterns
  96. complex genetics
    involves multiple mutations and environmental factors
  97. mutation:
    and change in genetic material
  98. what causes mutations?
    • no one knows! but...
    • an altered polypeptide product fails to fold correctly causing it to fail at its cellular function
  99. sickle cell anemia
    caused by a single base point subsitution in beta blobin gene on chromosome 11
  100. progression of sickle cell
    point mutation --> single amino acid substitution--> abnormal hemoglobin--> sickling erythrocytes
  101. outcomes of sickle cell
    • tower skull and long bones (anemia)
    • poor physical development (anemia)
    • impaired mental function (anemia)
    • weakness and lassitude (anemia)
    • heart failure
    • paralysis
    • pneumonia
    • abdominal pain
    • rheumatism
    • renal failure
    • splenomegaly
  102. 2 sources of mutation
    • radiation
    • chemical
  103. types of radiation causing mutation
    • cosmic rays
    • radioactive decay
    • x-rays
  104. types of chemicals causing mutations
    • polycyclic aromatic hydrocarbons
    • oxidative agents
  105. mutation classification
    • 1. loss of function (recessive)
    • 2. gain of function (dominant)
    • 3. dominant negative (dominant or co-dominant)
    • 4. lethal
  106. genetic load
    the mutational load of a person in their lifetime

What would you like to do?

Home > Flashcards > Print Preview