Biology 1115 chapter 14

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CanuckGirl
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249574
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Biology 1115 chapter 14
Updated:
2013-11-30 17:13:31
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Mendelian Genetics
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Mendelian,Genetics
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Mendelian Genetics
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  1. What was the "blending" hypothesis?
    it was the idea that genetic material from the two parents blends together
  2. What was the "particulate" hypothesis?
    it's the idea that parents pass on discrete heritable units (genes)
  3. How did Mendel discover the basic principles of heredity?
    by breeding garden peas in carefully planned experiments
  4. What are characters?
    distinct heritable features (ex. flower colour)
  5. What are traits?
    character variants (ex. purple or white flowers)
  6. What is true breeding?
    plants that produce offspring of the same variety when they self-pollinate
  7. Mendel mated two contrasting, true-breeding varieties a process called?
    hybridization
  8. The true-breeding parents are the _______________.
    P generation
  9. The hybrid offspring of the P generation are called the______________.
    F1 generation
  10. When F1 individuals self-pollinate, the __________ is produced.
    F2 generation
  11. What were the two laws that Mendel identified?
    • 1. Law of segregation
    • 2. Law of independent assortment
  12. What is heterozygous?
    an organism that has two different alleles for a gene
  13. What is homozygous?
    an organism with two identical alleles for a character
  14. What Mendel called a "heritable factor" is what we now call a?
    gene
  15. What are the 4 concepts that make up Mendel's model?
    • 1. alternative versions of genes account for variations in inherited characters
    • 2. for each character, an organism inherits two alleles, one from each parent.
    • 3. if 2 alleles at a locus differ, then one (dominant allele) determines the organism's appearance and the recessive allele has no effect.
    • 4. law of segregation, which states that the 2 alleles for a heritable character separate during gamete formation and end up in different gametes
  16. Alteration versions of a genes are now called?
    alleles
  17. Each gene resides at a specific locus on a specific chromosome, what is a locus?
    location or position on a chromosomes
  18. In the true breeding plants of Mendel's P generation, the two alleles at a locus on a chromosome __________.
    may be identical
  19. Two alleles in F1 hybrids at a locus may ________.
    differ
  20. What does the segregation of alleles correspond to in meiosis?
    corresponds to the distribution of homologous chromosomes to different gametes in meiosis
  21. P generation HAS to be?
    homozygous
  22. What is phenotype?
    physical appearance
  23. What is genotype?
    genetic makeup
  24. What does the law of segregation state?
    states that the two alleles for a heritable character separate (segregate) during gamete formation and end up in different gametes.
  25. What does the law of independent assortment state?
    states that each pair of alleles segregate independently of each other pair of alleles during gamete formation
  26. The law of independent assortment applies only to?
    genes on different, non-homologous chromosomes
  27. Genes located near each other on the same chromosome tend to be _____________>
    inherited together.
  28. When will Mendelian patterns not be the right situation to follow? (3)
    • When alleles are not completely dominant or recessive
    • when a gene has more than two alleles
    • when a gene produces multiple phenotypes
  29. When does complete dominance occur?
    occurs when phenotypes of the heterozygote and dominant homozygote are identical
  30. What is incomplete dominance?
    the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties
  31. What happens in codominance?
    two dominant alleles affect the phenotype in separate distinguishable ways
  32. What is Tay-Sachs disease?
    • fatal
    • a dysfunctional enzyme causes an accumulation of lipids in the brain
  33. In Tay-Sachs disease, at the organism level, is the allele recessive or dominant?
    recessive
  34. At the biochemical level, the phenotype of Tay-Sachs disease is?
    incompletely dominant
  35. At the molecular level in Tay-Sachs disease, the alleles are?
    codominant
  36. What is pleiotropy?
    genes that have multiple phenotypic effects
  37. What is epistasis? What is an example?
    • a gene at one locus alters the phenotypic expression of a gene at a second locus
    • coat colour in mice and other mammals
  38. What are quantitative characters? What does is usually indicate?
    • are those that vary in the population along a continuum
    • polygenic inheritance
  39. What is polygenic inheritance? what is an example?
    • an additive effect of two or more genes on a single phenotype
    • ex. skin colour in humans
  40. What is the norm of reaction? What is an example?
    • is the phenotypic range of a genotype influenced by the environment
    • hydrangea flowers of the same genotype range from blue-violet to pink, depending on soil acidity
  41. Polygenic characters are called multi-factorial because?
    because genetic and environmental factors collectively influence phenotype
  42. Am organism's phenotype reflects it's ____________ and_________________________.
    • overall genotype
    • unique environmental history
  43. What are 3 reasons why humans are not good subjects for genetic research?
    • generation time is too long
    • parents produce relatively few offspring
    • breeding experiments are unacceptable
  44. What is a pedigree?
    is a family tree that describes the interrelationships of parents and children across generations
  45. Recessively inherited disorders show up only in individuals __________ for the allele.
    homozygous
  46. What are carriers?
    are heterozygous individuals who carry the recessive allele but are phenotypically normal
  47. what is an example of a recessive condition?
    albinism
  48. What is consanguineous matings?
    mating between two close relatives
  49. What does the cystic fibrosis allele result in?
    results in a defective or absent chloride transport channels in plasma membrane.
  50. Dominant alleles that cause a lethal disease are _____ and arise by mutation
    rare
  51. define Achondroplasia.
    form of dwarfism caused by a rare dominant allele
  52. What is Huntington's disease?
    degenerative disease if the nervous system

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