Final answer:
When parents with Aa genotypes are crossed, the possible offspring genotypes are AA, Aa, and aa. For a cross of true-breeding parents with green (yy) and yellow (YY) seeds, all F1 offspring will have yellow seeds (Yy). Punnett squares are essential tools for visualizing genetic crosses and predicting offspring genotypes and phenotypes.
Step-by-step explanation:
When parents with genotypes Aa and Aa for seed color in pea plants are crossed, the possible genotypes of the offspring include AA (homozygous dominant), Aa (heterozygous), and aa (homozygous recessive). This results from each parent being able to contribute either an A (dominant allele for yellow seed color) or an a (recessive allele for green seed color). Therefore, the correct answer is a) AA, Aa, aa.
When performing a cross involving true-breeding garden pea plants, if one parent has green seeds (yy) and the other has yellow seeds (YY), all the F₁ offspring would be expected to have yellow seeds because yellow is the dominant color. This results in genotypes Yy for all F₁ offspring. Hence, the correct answer is b) 100 percent yellow seeds.
Punnett squares are used to predict the outcomes of genetic crosses. They show the combinations of egg and sperm alleles and thus the possible genotypes of the offspring. For a monohybrid cross of two true-breeding parents, we can infer that with dominant yellow seeds and recessive green seeds, the F₁ offspring will all display the dominant phenotype, meaning they all have yellow seeds.