Genotype, phenotype and offspring ratios

Answer Key - Grade 7 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Ari's class grows 48 plants from a Gg × Gg pea cross. About how many would you expect to be Gg?

   24
2. 2.

   Bo reads about 200 plants from an Ii × Ii pea cross. About how many would you expect to be II?

   50
3. 3.

   Esme's class grows 64 plants from an Aa × Aa pea cross. About how many would you expect to be Aa?

   32

4. Read this first

   Mendel's results, as reported by OpenStax Biology 2e Table 12.1

   trait	first generation	second generation
   pod color	100 percent green	428 green and 152 yellow

5. 4.

   Kira reads Mendel's counts for pod color. Of the 428 green-pod plants, about what share would you expect to be Gg?

   • About 2 of every 3
   • About 1 of every 2
   • Zero: green-pod plants are GG
   • About 1 of every 3
6. 5.

   In Luz's table, terminal flowers vanish in the first generation and return in the second. Which explanation fits?

   • The first plants were Aa, which show terminal flowers
   • The first plants were Aa; two Aa parents gave some aa
   • The two flower positions blended, then split apart again
   • The first plants were AA, then later changed to Aa
7. 6.

   From a Gg × Gg cross, Milo picks one green-pod offspring at random. What is the chance it is Gg?

   • 2 in 3: two of the three green boxes are Gg
   • Zero: green pods mean the plant is GG
   • 1 in 2: two of the four boxes are Gg
   • 3 in 4: three of the four boxes are green
8. 7.

   Noah crosses an inflated-pod plant with an ii plant. Some offspring have constricted pods. What is the inflated plant's genotype?

   • Ii: it passed an i to some offspring
   • ii: constricted offspring need two ii parents
   • Ii: a plant with an i shows constricted pods
   • II: it looks inflated
9. 8.

   Pia's class garden wants pea plants that are AA. Why can't the class tell AA from Aa just by looking?

   • Both show axial flowers, since A is dominant
   • Aa plants have flowers halfway up the stem
   • Axial plants are AA each time, so it is easy
   • Aa plants show terminal flowers, so they stand out
10. 9.

    Tala says two pea plants with the same phenotype must have the same genotype. Agree or disagree?

    • Disagree: GG and Gg both have green pods
    • Disagree: Gg plants have yellow pods
    • Agree: the look shows the two letters
    • Agree: a green-pod plant is GG, as green is dominant
11. 10.

    Zee says an Ii pea plant has constricted pods because it carries an i. Agree or disagree?

    • Agree: any i makes the pods constricted
    • Disagree: I is dominant, so Ii pods are inflated
    • Agree: Ii pods are half constricted
    • Disagree: Ii plants show a 1 : 2 : 1 look