Chapter 14 & 15

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Chapter 14 & 15
2012-12-09 20:46:40
BI 253

Ch 14-15 12-3-12
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  1. The term used to describe the composition of an organism's alleles for a gene is what?
  2. The termed to describe the "expression of the genotype" or the physical appearance of an organism is ____.
  3. What is the difference between genotype & phenotype?
    Genotype is the composition of an organisms alleles for a gene where as phenotype is the organism's physical appearance or "expression of the gene"
  4. What is an allele?
    Different forms of a gene that occupy the same locus or position on a chromosome
  5. A trait that is expressed preferentially over another trait is known as the ____ trait.
  6. A trait that is preferentially masked is a ____ trait.
  7. What term describes the situation when 2 different alleles at a locus are responsible for different phenotypes & both alleles affect the phenotype of the heterozygote?
  8. Where do we see codominance come into play?
    When looking at blood types
  9. ____ ____ is the term used to describe a situation when 1 allele is not completely dominant over another & you wind up w/something in the middle.
    Incomplete Dominance
  10. When speaking of alleles what letters are used for dominant & recessive traits?
    • Capital letters for Dominant
    • Lower case letters for recessive
  11. What happens when alleles fr 1 gene cover up or alter expression of alleles of another gene?
  12. What is meant by pleiotropic alleles?
    This occurs when a single allele has more than 1 phenotypic effect
  13. Color pattern & crossed eyes in siamese cats are caused by the same allele. What is this phenomenon called?
    Pleiotropic Alleles
  14. What is Mendel's First Law & what does it say?
    Law of Segregation says that alleles segregate fr one another during formation of gametes
  15. Mendel's 2nd Law, the Law of ____ ____says alleles of different genes are assorted independently of one another during the formation of gametes.
    Independent Assortment
  16. According to Mendel's Law of ____ 2 copies of a gene separate & each gamete receives 1 member of the pr of alleles.
  17. When is a test cross utilized?
    When we want to determine the genotype of an organism
  18. The breeding of an organism of an unk genotype w/a homozygous rec individual to determine what the unk genotype is is known as a ____ ____.
    Test Cross
  19. When doing a test cross how do we determine the unk genotype?
    By breeding the organism w/unk geno w/homozygous rec individual & examining phenotype of offspring
  20. Homozygous describes what allele makeup?
    2 copies of the same allele
  21. Heterozygous describes what allele makeup?
    Individuals w/2 different alleles of the same gene
  22. What is difference between homozygous & heterozygous?
    In a homozygous individual both alleles for a trait are the same (YY or yy) & can be rec or dom whereas heterozygous individuals have different alleles for a trait (Yy)
  23. An organism that is heterozygous w/respect to a SINGLE gene of interest is a ___.
  24. An organism that is heterozygous w/respect to 2 genes of interest is a ____.
  25. A gene coded on a sex chromosome is known as a ___-___ gene.
  26. What is the genotype for Type A blood?
    IA IA or IA i
  27. What is the genotype for Type B blood?
    IB IB or IB i
  28. If blood has the genotype IA IB it is Type ___ blood.
  29. What is the genotype for Type O blood?
  30. In human blood types, the alleles __ & __ are codominant & ____ over the recessive allele ___.
    • IA & IB
    • Dominant
    • ii
  31. What is the term used to describe a situation where 1 trait is controlled by 3 genes?
    Polygenic Inheritance
  32. Give 1 example of polygenic inheritance.
    • Production of melatonin
    • 3 genes are responsible
    • Each allele is additive
  33. A diagram that shows phenotypes of several different generations is called a ____.
  34. What is a pedigree used for?
    Mostly in clinical evaluation & counseling of pts w/inherited abnormalities
  35. What shape is used to symbolize females on a pedigree chart?
  36. What shape is used to symbolize males on a pedigree chart?
  37. A black square/circle on a pedigree chart shows what?
    Presence of the cond being studied
  38. A white square/circle on a pedigree chart means what?
    The condition being studied is absent
  39. What did Thomas Morgan figure out?
    That genes are carried on chromosomes
  40. The Y chromosome carries very few genes where as the X carries approx ____.