Question

based on mendels pea plant punnett square crosses, what will be the probability that a pea plant will be yellow if two heterozygous dominant pea plants are crossed? parent 1 yy parent 2 yy 75% 25% 50% 100%

Explanation:

Step1: Recall Mendel's Genetics

In Mendelian genetics, for a heterozygous dominant cross (Yy × Yy), we use a Punnett Square. The alleles from Parent 1 (Yy) are Y and y, and from Parent 2 (Yy) are Y and y.

Step2: Construct Punnett Square

The Punnett Square will have four cells:

• Top - left: Y (from Parent 1) × Y (from Parent 2) = YY
• Top - right: Y (from Parent 1) × y (from Parent 2) = Yy
• Bottom - left: y (from Parent 1) × Y (from Parent 2) = Yy
• Bottom - right: y (from Parent 1) × y (from Parent 2) = yy

Step3: Determine Phenotype Ratios

The dominant trait (yellow, for Y) is expressed in YY, Yy, Yy. So 3 out of 4 genotypes show the yellow phenotype.

Step4: Calculate Probability

To find the percentage, we calculate $\frac{3}{4} \times 100\% = 75\%$.

Answer:

75% (corresponding to the option "75%")