Mendel obtained wrinkled seeds in pea due to deposition of sugars instead of starch. It was due to which enzyme : -
A
Amylase
B
Invertase
C
Diastase
D
Absence of starch branching enzyme
The answer is D.
Solution
The R gene of pea codes for starch branching enzyme (SBE1), which converts amylose into amylopectin. In rr plants, a mutation (a transposon insertion) makes this enzyme non-functional. Less starch is made and more sugar accumulates in the seed. The extra sugar draws in water by osmosis while the seed develops; when the seed matures and dries, it loses this water and shrinks, so it becomes wrinkled. So wrinkled seeds were due to the absence of the starch branching enzyme.
ConceptStarch branching enzyme and wrinkled seeds
Principles of Inheritance and Variation in past papers
198 questions from this chapter have appeared across 27 exam years.
