Question

a plant heterozygous for yellow seeds is crossed with a plant homozygous for green seeds. use the punnett square to predict the phenotype of the offspring. 1 yellow 2 3 yellow 4 green done

Explanation:

Step1: Determine Genotypes

The heterozygous yellow - seeded plant has genotype \(Yy\) (since yellow is dominant, let \(Y\) represent yellow allele and \(y\) represent green allele), and the homozygous green - seeded plant has genotype \(yy\).

Step2: Analyze Punnett Square Cells

- Cell 1: Cross \(Y\) (from \(Yy\)) and \(y\) (from \(yy\)), genotype \(Yy\), phenotype yellow.
- Cell 2: Cross \(y\) (from \(Yy\)) and \(y\) (from \(yy\)), genotype \(yy\)? Wait, no, wait. Wait, the top row is \(Y\) and \(y\) (from \(Yy\) plant), and the left column is \(y\) and \(y\) (from \(yy\) plant). So cell 2: \(y\) (top) and \(y\) (left) → genotype \(yy\)? Wait, no, no, the heterozygous plant is \(Yy\), so it produces gametes \(Y\) and \(y\). The homozygous green plant (\(yy\)) produces gametes \(y\) and \(y\). So Punnett square:
- Top row: \(Y\) (gamete from \(Yy\)) and \(y\) (gamete from \(Yy\))
- Left column: \(y\) (gamete from \(yy\)) and \(y\) (gamete from \(yy\))
- Cell 1: \(Y\) (top) and \(y\) (left) → \(Yy\) (yellow)
- Cell 2: \(y\) (top) and \(y\) (left) → \(yy\) (green)? Wait, no, wait the problem's Punnett square: Wait, the left column has two \(y\)s (since the green plant is \(yy\)). The top row has \(Y\) and \(y\) (from \(Yy\) plant). So cell 2: \(y\) (top) and \(y\) (left) → genotype \(yy\), phenotype green? Wait, but the first dropdown is yellow for cell 1. Wait, maybe I made a mistake. Wait, the heterozygous yellow is \(Yy\) (yellow dominant), homozygous green is \(yy\) (green recessive). So when we cross \(Yy\times yy\), the Punnett square is:
| | \(Y\) | \(y\) |
|---|---|---|
| \(y\) | \(Yy\) (yellow) | \(yy\) (green) |
| \(y\) | \(Yy\) (yellow) | \(yy\) (green) |

Wait, but in the given Punnett square, cell 2: let's re - examine the image. The top row is \(Y\) and \(y\), left column is \(y\) and \(y\). So cell 2 is the intersection of \(y\) (top) and \(y\) (left), so genotype \(yy\), phenotype green. But wait, the first cell (cell 1) is \(Y\) and \(y\) → \(Yy\) (yellow). Cell 2: \(y\) and \(y\) → \(yy\) (green). But the dropdown for cell 2 has options yellow and green. Wait, maybe I messed up the gametes. Wait, the heterozygous plant is \(Yy\) (yellow), so yellow is dominant. So \(Y\) is dominant over \(y\). So \(Yy\) is yellow, \(yy\) is green. So when we cross \(Yy\times yy\), the offspring genotypes are \(Yy\) (50%) and \(yy\) (50%). So phenotypes: 50% yellow (\(Yy\)) and 50% green (\(yy\)). So cell 2: genotype \(yy\), phenotype green. But the first cell (cell 1) is \(Yy\) (yellow). So for cell 2, the phenotype should be green? Wait, no, wait the Punnett square in the image: cell 2 is in the top row ( \(y\) column) and left column ( \(y\) row). So \(y\) (from top) and \(y\) (from left) → \(yy\), which is green. But the first dropdown for cell 1 is yellow (correct, since \(Yy\) is yellow). So for cell 2, the phenotype is green. Wait, but the options for cell 2 are yellow and green. So the correct option for cell 2 is green. Wait, but let's check again. Wait, the heterozygous plant is \(Yy\) (yellow), homozygous green is \(yy\). The cross \(Yy\times yy\) gives:
- Gametes from \(Yy\): \(Y\) and \(y\)
- Gametes from \(yy\): \(y\) and \(y\)
- Offspring:
- \(Y + y=Yy\) (yellow)
- \(y + y = yy\) (green)
- \(Y + y=Yy\) (yellow)
- \(y + y = yy\) (green)

So in the Punnett square, cell 2 (second cell in the top row and first column row) has genotype \(yy\), so phenotype green.

Step3: Select the Correct Phenotype

From the dropdown options for cell 2, the options are yellow and green. Since the genotype of cell 2 is \(yy\), the phenotype is green.

Answer:

green