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 shape	100 percent inflated	882 inflated and 299 constricted

5. 4.

   Jun reads Mendel's second-generation counts for pod shape. About what ratio is this, and what were the parents' genotypes?

   • About 3 to 1, so both parents were II
   • About 1 to 2 to 1 of the pod shapes
   • About 3 to 1, so both parents were Ii
   • About 1 to 1, so the parents were Ii and ii
6. 5.

   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 3
   • Zero: green-pod plants are GG
   • About 1 of every 2
7. 6.

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

   • The first plants were Aa; two Aa parents gave some aa
   • The first plants were AA, then later changed to Aa
   • The first plants were Aa, which show terminal flowers
   • The two flower positions blended, then split apart again
8. 7.

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

   • 1 in 2: two of the four boxes are Gg
   • Zero: green pods mean the plant is GG
   • 3 in 4: three of the four boxes are green
   • 2 in 3: two of the three green boxes are Gg
9. 8.

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

   • ii: constricted offspring need two ii parents
   • Ii: it passed an i to some offspring
   • II: it looks inflated
   • Ii: a plant with an i shows constricted pods
10. 9.

    Ren says a Gg × Gg cross gives a 1 : 2 : 1 ratio of pod colors. Agree or disagree?

    • Disagree: 1 : 2 : 1 is genotypes; colors are 3 : 1
    • Disagree: the colors come out 1 : 1
    • Agree: each genotype has its own pod color
    • Agree: genotype and phenotype ratios are the same
11. 10.

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

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