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Analyzing Mendelian Genetics (journal)

Plant Height Experiment

  1. Mendel studied how garden peas inherited plant height. He started with two true-breeding lines, one producing tall plants, the other short plants. We will use the capital letter "T" to represent the tall allele and a lowercase "t" for the short allele.
    1. We call these plants the parental generation, abbreviated as the  ___   generation.
    2. What is the genotype for the true-breeding tall plants ?
    3. Describe the phenotype for the tt plants.
    4. Why are these plants called homozygous?
  2. Mendel crossed the two lines. He did this by placing pollen (male gametes) of a tall plant on the pistil (female part) of a short plant. Remember that a gamete will have ½ of the parent's genome. He saved the resulting seeds.
    1. What is the gamete allele of the true-breeding tall plants?
    2. What is the gamete allele of the true-breeding short plants?
  3. Mendel grew the seeds of this first crossed generation. He found that the plants were all tall!
    1. The plants grown from the seeds are known as the  __  generation.
    2. What is the genotype of the plants ?
    3. Which height trait is dominant?
    4. Are these plants homozygous for height?
    5. The gametes of these F1 plants have two possible alleles:    
  4. Mendel then did nothing... these F1 plants self-fertilized themselves. When Mendel planted the resulting F2 seeds he found that 75% of the F2 plants were tall and 25% were short.
    1. What are the three genotypes contained in the F2 seeds?        
    2. What is the genotype of the short plants ?
    3. What are the genotypes of the tall plants ?    
    4. Which two genotypes would be true-breeding now ?    
    5. Which two genotypes would be homozygous ?    

Pod Color Experiment

  1. Mendel also studied the pod color of garden peas. He started with two true-breeding lines, one producing green pods, the other yellow pods. We will use letter "G" to represent the green pod allele and a lowercase "g" for the yellow pod allele.
    1. We call these true-breeding plants the  __   generation.
    2. What is the genotype for the true-breeding green pod plants ?
    3. Describe the phenotype for the gg plants.
    4. Are these plants homozygous for pod color?
    5. What is the gamete allele of the true-breeding green pod plant?
    6. What is the gamete allele of the true-breeding yellow pod plant?
  2. Mendel crossed these two lines, saved the resulting F1 seeds and grew them into F1 plants.
    1. What is the genotype of the plants ?
    2. Describe the phenotype of the plants.
    3. Are these plants homozygous for pod color?
    4. The gametes of the F1 plants have two possible alleles:    
  3. Mendel allowed the F1 plants to self-fertilize. When he planted the resulting F2 seeds they grew into a mix of green and yellow pod F2 plants.
    1. What percentage of the plants had a GG genotype?
    2. What percentage of the plants had a Gg (or gG) genotype?
    3. What percentage of the plants had a gg genotype?
    4. Describe the phenotype for the Gg (or gG) plants.
    5. Which two genotypes would be true-breeding now ?    
    6. Which genotypes would be heterozygous ?    
    PLANT HEIGHT EXPERIMENT            |         POD COLOR EXPERIMENT
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    F1 Punnett Square                  |         F1 Punnett Square
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    F2 Punnett Square                  |         F2 Punnett Square
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    A1. _________________________      |     A1. _________________________
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    A2. _________________________      |     A2. _________________________
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    A3. _________________________      |     A3. _________________________
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    A4. _________________________      |     A4. _________________________
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    B1. _________________________      |     A5. _________________________
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    B2. _________________________      |     A6. _________________________
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    C1. _________________________      |     B1. _________________________
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    C2. _________________________      |     B2. _________________________
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    C3. _________________________      |     B3. _________________________
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    C4. _________________________      |     B4. _________________________
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    C5. _________________________      |     C1. _________________________
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    D1. _________________________      |     C2. _________________________
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    D2. _________________________      |     C3. _________________________
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    D3. _________________________      |     C4. _________________________
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    D4. _________________________      |     C5. _________________________
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    D5. _________________________      |     C6. _________________________
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