Question

when mendel cross-pollinated purple-flowered and white-flowered parent plants, what did he observe?

a white-flowered plants disappeared in the f1 generation.
b white-flowered plants disappeared in the f2 generation.
c purple-flowered plants disappeared in the f2 generation.
d purple-flowered plants disappeared in the f1 generation.

Explanation:

Analyze the F1 generation phenotype

Mendel crossed true-breeding purple-flowered (\(PP\)) and white-flowered (\(pp\)) parent plants. The resulting \(F_1\) generation offspring all had the heterozygous genotype (\(Pp\)) and exhibited the dominant purple-flower phenotype.

Determine the status of white-flowered plants

Because all \(F_1\) plants had purple flowers, the white-flowered trait was not expressed in this generation. Thus, white-flowered plants disappeared in the \(F_1\) generation.

Evaluate the F2 generation

When the \(F_1\) plants self-pollinated, the white-flowered trait reappeared in the \(F_2\) generation in a \(3:1\) ratio of purple to white flowers. Therefore, white-flowered plants did not disappear in the \(F_2\) generation.

Answer:

• a White-flowered plants disappeared in the F1 generation. (Correct answer)
• b White-flowered plants disappeared in the F2 generation.
• c Purple-flowered plants disappeared in the F2 generation.
• d Purple-flowered plants disappeared in the F1 generation.