BIO 1201 Test 3

BIO 1201 Test 3 - Gregor Mendel Inheritance is particulate...

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Gregor Mendel Inheritance is particulate rather than blending Mendel worked with edible pea plants -Long history of previous works on pea plants -Why did he succeed and other fail? John Gross Englishmen who worked with them prior to Mendel He observed green and yellow peas and did exactly what Mendel did But he did not count and record his data Why did Mendel succeed? Mendel chose the right organism to work with (pea plants) The plant self pollinates Stigma and anthers are completely enclosed by the petals until after fertilization He picked the right gene traits to follow Simple single gene inheritance He followed the crosses for several generations He recorded his observations Had help from friends Definitions and Terminology Gene - discrete unit of hereditary information consisting of a specific sequence of DNA; often codes for a polypeptide chain Gene Locus - Specific region on the chromosome where the DNA is located Allele - alternative form of a gene; one allele codes purple while the other codes white; Examples: Aa, Bb, I A , I B , i Homozygous - showing to identical alleles; example: AA, BB, ii Heterozygous - having 2 different alleles; example: Aa, Fig. 14.4
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Genotype - genetic makeup of an individual Phenotype - physical manifestation of a trait determined by the genotype Dominant Allele - allele that’s fully expressed in the phenotype of a heterozygote; only a single copy is required to express this trait; represented by a capital letter Recessive Allele - in a heterozygote it is not expressed in the phenotype; represented by a lower case letter Why it is not expressed? -Inactive or defective enzyme Generations P- Parental F1- Filial one; offspring of the parental generation (hybrid) F2- Filial two; offspring of cross between F1 (hybrid) individuals Punnett Square P p PP Pp Pp pp P p
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Mendel’s first Law : The 2 members of a gene pair separate from each other into the gametes -Each gamete carries one member of the gene pair o Mendelian segregation occurs in Anaphase I (homologous chromosomes separate & alleles segregate into different gametes Test Cross Fig 14.7 How do you determine if an individual is homozygous dominant or recessive? Phenotype is A Genotype is A_ Would either be AA or Aa Cross the unknown individual with a homozygous recessive individual Test Cross Outcomes: Unknown homozygous dominant- all offspring display the dominant trait Unknown heterozygous- ½ display dominant and ½ display recessive Blood type B B antigens B polysaccharides on the surface of the Red Blood Cell Blood type AB A antigens and B antigens Co dominant Blood type O no antigens is recessive Serum Antibodies Blood type A anti-B bodies blood type A recognizes the B polysaccharides
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This note was uploaded on 04/19/2010 for the course BIOL 1201 taught by Professor Wishtichusen during the Spring '07 term at LSU.

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BIO 1201 Test 3 - Gregor Mendel Inheritance is particulate...

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