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28 Cards in this Set
- Front
- Back
Who was Mendel?
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discovered the basic principles of heredity by breeding garden peas in carefully planned experiments |
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Why did he work with peas? There are several answers to this…name a few.
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There are many varieties with distinct heritable characters character variants are called traits He could control mating between plants |
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True-breeding purple peas produce what color offspring?
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Purple |
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True-breeding white peas produce what color offspring?
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White |
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Why do we only see differences in the F2 hybrids when we start with true-breeding purple and true-breeding white pea plants?
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Ratio of about three to one |
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What are the four related concepts the Mendel developed to explain his model?
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Alleles account for variations in inherited characters for each character, an organism inherits two alleles, one from each parent if the two alleles at a locus differ, then the dominant allele determines the organism’s appearance, and the recessive allele has no noticeable effect on appearance the law of segregation |
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What accounted for the differences seen in the F2 hybrids? What do we call thee different versions of a gene?
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3:1 ratio; |
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How do we represent a dominant allele? How do we represent a recessive allele?
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A capital letter represents a dominant allele, and a lowercase letter represents a recessive allele |
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What is the difference between a homozygote and a heterozygote?
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Homozygote: An organism with two identical alleles for a character heterozygote: An organism that has two different alleles for a gene |
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Why would we be interested in performing a testcross?
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tell the genotype of an individual with the dominant phenotype |
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Why are we interested in the law of independent assortment? What does that mean for a sexually reproducing species?
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each pair of alleles segregates independently of any other pair during gamete formation ; |
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Genes located near each other on the same chromosome tend to be inherited _________________
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together |
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How does incomplete dominance compare to complete dominance? Example?
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incomplete dominance: the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties Complete dominance: occurs when phenotypes of the heterozygote and dominant homozygote are identical |
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How does codominance compare to complete dominance? Example?
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codominance: two dominant alleles affect the phenotype in separate, distinguishable ways Complete dominance: occurs when phenotypes of the heterozygote and dominant homozygote are identical |
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Is the dominant allele always the most common?
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No |
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How can epistasis affect the phenotype?
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a gene at one locus alters the phenotypic expression of a gene at a second locus |
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Can we have multiple genes governing (controlling) one trait? Example.
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Yes; coat color depends on two genes |
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Can we have one gene governing multiple traits? Example.
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Yes; Skin color |
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What is involved in the phenotype?
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Physical appearance, internal anatomy, physiology, and behavior |
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Why are peas (and other short-lived animals) good subjects for genetic research?
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Don't have a lot of restrictions like humans. |
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Why are humans not good subjects for genetic research?
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Generation time is too long
Parents produce relatively few offspring Breeding experiments are unacceptable |
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For what can we use a pedigree?
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described the interrelationships of parents and children across generations: used to make predictions about future offspring
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What is the phenotype of a carrier?
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Phenotypically normal |
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Why do we kind of “frown on” consanguineous marriage?
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Mating increase the chance of mating between two carriers of the same rare allele |
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Are all disorders recessive traits?
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No; Dominant alleles that cause a lethal disease are rare |
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Is it possible to have a genetic disorder and not know about it until later in life?
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Yes |
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Name some other diseases that might have some genetic components.
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heart disease, diabetes, alcoholism, mental illnesses, and cancer |
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When might it be a good idea to have genetic counseling for yourself and you spouse?
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When deciding if you want to start a family |