Question

Consider a cross to investigate the pea pod texture trait, involving constricted or inflated pods. Mendel found that the traits behave according to a dominant/ recessive pattern in which inflated pods were dominant. If you performed this cross and obtained 650 inflated-pod plants in the F2 generation, approximately how many constricted-pod plants would you expect to have?
A. 600
B.165
C. 217
D. 468

Answer 1

Answer:

C. 217

Explanation:

Mendel obtained the phenotypic ratio of 3 dominant: 1 recessive in the F2 generation of a monohybrid cross. According to the given information, inflated pods are dominant over the constricted one.

Let's assume that the allele C is responsible for inflated pods while the recessive allele "c" gives constricted pods. A cross between two pure breeding plants with inflated (CC) and constricted pods (cc) would give all the plants with inflated pods (Cc) in the F1 generation. A cross between two F1 plants would obtain F2 generation in following ratio=3 Inflated: 1 constricted.

Therefore, if 650 plants with inflated pods were obtained in the F2 generation, 217 plants must have constricted pods since 650:217 is almost equal to 3:1.