Question

2a. The enzyme called Pheide a Oxygenase (PAO) catalyses the degradation of chlorophyll. Mendel’s I gene (yellow peas) codes for this enzyme. If this gene is mutated, what will happen to the pea colour? 2b. What was discovered when looking at the PAO levels between heterozygous and homozygous plants? 2c. Gibberellin is a plant hormone that promotes the elongation of plant stems. It is produced in a series of reactions requiring an enzyme coded for by a specific gene. If this gene is isolated, and mutated, how will this affect the height of the plant? 2d. Mendel’s R gene (round peas) codes for the enzyme Starch-branching enzyme isoform (SBEI) which forms 1,6 linkages in starch, producing Amylopectin. If 1,4 linkages were produced instead, what type of starch would be formed? This would cause the peas to display recessive traits. How will the peas look and taste?

Answer 1

2a. Yellow peas are dominant (Y). Green peas are recessive (y). Peas that are green in color are immature peas. When the pea ripened, the chlorophyll will broken down in the pathway. The pea will eventually turns to yellow. The enzyme responsible for this process is Pheide a Oxygenase (PAO) .

If the gene is mutated, PAO will not be produced. Pea will remain green because chlorophyll will not be broken down.