Question

In corn (zea mays, purple kernels (r are dominant to yellow kernels (r. cobs from the offspring of a cross between a purple plant and yellow plant were used in a lab. a student counts 329 purple and 299 yellow kernels on one cob.

Answer 1

In corn, purple kernels (R) are dominant to yellow kernels (r). The possible genotypes for the cross between a purple plant and a yellow plant are RR (purple) and Rr (50% purple, 50% yellow).

Step-by-step explanation:

In corn, purple kernels (R) are dominant to yellow kernels (r). In the given cross between a purple plant and a yellow plant, the student counted 329 purple and 299 yellow kernels on one cob. To determine the possible genotypes of the parent plants, we can use a Punnett square. Since purple is dominant, the purple plant can be either homozygous dominant (RR) or heterozygous (Rr), while the yellow plant must be homozygous recessive (rr).

To construct the Punnett square, we can represent the genotypes of the parent plants as follows:

Purple plant (R-): RR or Rr

Yellow plant (r-): rr

Possible genotypes and phenotypes for the offspring:

Genotype: RR (purple) = 100% chance of purple

Genotype: Rr (purple) = 50% chance of purple, 50% chance of yellow

Therefore, the possible genotypes and phenotypes for the cross between a purple plant and a yellow plant are RR (purple) and Rr (50% purple, 50% yellow).

Answer 2

X² = 1.44

Explanation:

Purple= R, and R is dominant on r

yellow =r,

As given, cross between a purple heterozygous corn plant (Rr) and a recessive yellow corn plant (rr)

yield offspring that display a 1:1 ratio between purple kernels and yellow kernels. Of the total kernels,

it would be expected that 279 would be purple and 279 would be yellow but here results are little differ. The chi-square value is

calculated as: the range of acceptable result should be 1.43-1.44.

Phenotype observed, expected, obs-exp, (obs-exp)2 (obs-exp)2/exp

Purple 329 314 15 225 0.72

Yellow 299 314 -15 225 0.72

X² = 1.44