Biology Exam 3

Biology Exam 3 - Biology 1201 Exam 3 and 4 CHAPTER 14, 15,...

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Biology 1201 Exam 3 and 4 Gregor Mendel Born 1822 Monk a monastery in Czech Republic 1866 published his work “experiment with plant hybrids” Rediscovered in 1900 by Hugo de… “Particulate” rather than “blending” inheritance Mendel’s experiment succeeded over Goss because he chose right organism to work with, edible pea plants. o Used quantitative data Picked right traits to follow He followed the crosses for several generations Why did Mendel succeed? He chose the right organism to work with, the edible pea plant. o The plant usually self-pollinates, i.e., self fertilizes. o Stigma and anthers are completely enclosed by petals until after fertilization o Therefore there is no cross contamination Picked the “right” traits to follow o Simple single gene inheritance. He followed the crosses for several generations. He was quantitative in his observations. He had little help form his friends. Why don’t we talk about Gossian genetics? Goss was not quantitative Fig. 14.3 & 14.1
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Biology 1201 Exam 3 and 4 Definitions/ Terminology Gene - discrete unit of hereditary information consisting of a specific sequence of DNA o Often codes for a polypeptide chain Gene locus - a particular position along a specific chromosome where a given gene is located. Allele - alternative form of a gene. Homozygous Having 2 identical alleles for a trait AA aa I A I A I B I B ii Heterozygous Having two different genes (alleles) for a trait Aa I A I B Genotype The genetic makeup of an individual Phenotype The physical manifestation of a trait o How it appears o Determined by the genotype
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Biology 1201 Exam 3 and 4 How many different alleles can a diploid individual have at a single gene locus if there are 4 alleles in the population? Two Dominant Allele Allele that is fully expressed in the phenotype of a heterozygote Only a single copy is required to express the trait Represented by a capital letter (A) Recessive Allele In a heterozygous individual the allele that is completely masked (not expressed) in the phenotype Represented by the lower case letter (a) Why is it not expressed (recessive alleles)? Inactive or defective enzyme Generations P o Parental F1 o Filial one-offspring of the parental generation-hybrids F2 o Filial two - offspring of cross between F1 (hybrid) generations or individuals. Fig. 14.3 Mendel’s First Law The two members of a gene pair segregate (separate) from each other into gametes
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Biology 1201 Exam 3 and 4 Each gamete carries one member of the gene pair When do homologus chromosome separate? Anaphase I
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Biology Exam 3 - Biology 1201 Exam 3 and 4 CHAPTER 14, 15,...

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