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Test Review - Genetics

  1. Gregor Mendel used pea plants to studyinheritance traits in peas

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  1. Offspring that result from crosses between true-breeding parents with different traitshybird
  1. The chemical factors that determine traits are calledgenes
  1. The principle of dominance states thatif a dominant allele is present, then it will be seen in the phenotype

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  1. When you flip a coin, what is the probability that it will come up tails? ½ What is the probability that it will come up heads three times in a row? ½ x ½ x ½ = 1/8

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  1. Organisms that have two identical alleles for a particular trait are said to behomozygous

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  1. Situations in which one allele for a gene is not completely dominant over another allele for that gene (blending of traits) are called? Incomplete dominance

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  1. A cross of a red cow (RR) with a white bull (WW) produces all roan offspring (RW). This type of inheritance is known ascodominance

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  1. Variation in human skin color is a result ofmany genes = polygenic traits

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  1. If an organism’s diploid number is 36, its haploid number is18

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  1. Gametes are produced by the process of meiosis

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  1. meiosis results in? 4 different haploid cells

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  1. How many chromosomes are shown in a normal human karyotype? 46 or 23 pairs

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  1. What are the sex chromosomes for males? XY
  1. In a pedigree, what does a shaded circle represent? Female with the trait expressed
  1. What are all the chromosomes EXCEPT the sex chromosomes called? autosomal
  1. The different forms of a gene are what? Alleles
  1. If you flip a coin five times and it comes up heads each time, the probability that it will be heads the next time is? 1/2
  1. An organism must inherit ___both______recessive alleles for a trait in order to show that trait.
  1. The “matching” chromosomes from each parent in a human karyotype are _homologous chromosomes.
  2. During meiosis, what happens to the chromosome number? Reduced by half
  1. The physical appearance of an organism is its _phenotype__.
  2. . gametes are haploid / diploid

definitions:

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  1. heterozygousdifferent alleles
  2. probability- chance of something occuring
  3. codominance- both traits are expressed
  4. hybridization- cross between tow homozygous or similar individuals
  5. polyploid- 3n, 4n, etc
  6. recombinant DNA- DNA put into another organism
  7. clone- exact genetic copy (usually does not include mitochondrial DNA)
  8. pedigree- family tree used to follow traits
  9. recessive trait – will not be expressed unless there are no dominant alleles present

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  1. If redfour o’clock flowers (RR) and ivory-flowered four o’clock flowers (WW) are crossed, pink four o’clock flowers are produced. If two pink-flowered four o’clock flowers are crossed, what percent will be white? 25%
  1. On a gene map of a fruit fly’s chromosome which two genes will cross-over occur most frequently? gene A is at 12 gene B is at 24 gene C is at 36 gene D is at 95 - A and D
  1. Understand how to read a Dihybrid Punnett square such as RRYy x RrYY
  1. In a pedigree, what symbol would represent a male with adisease? Shaded in square
  2. In a pedigree of a sex-linked trait, what symbol would represent a female(s) that is a carrier? circle
  3. How is sex-linked trait inherited? Usually by the X chromosome and by one parent
  4. Know the steps of meiosis. – NOT ON THE TEST