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Brother Gregor Mendel chose pea plants as his model partially for their flower shape, which helps prevent cross-pollination. One of the characteristics he focused on was the shape of the pea seed. Some pea seeds are wrinkled, and some pea seeds are smooth in their appearance. When Mendel crossed plants grown from round (or smooth) pea seeds with plants grown from wrinkled pea seeds, the first generation pea seeds were all round and smooth. He called it the F1 generation. When he crossed two offspring from the first generation, the second generation (F2) produced an almost perfect 3:1 phenotypic ratio. Three-fourths of the second generation produced round seeds, and one-fourth produced wrinkled seeds. Combined with his studies of six other traits, Mendel concluded that pea plant traits were governed by two determiners (we now call these genes). One of the determiners was contributed by the pollen, the other by the pea-plant ovule. His further conclusion, important to this learning experience, was that smooth pea seed factors are dominant to factors for wrinkled pea seeds.

Mendel’s findings were made before knowledge of cell structure. He knew nothing about chromosomes and genes. He was not aware of the diploid state found in most eukaryotic cells. But he was a mathematician, and he did deduce the probability that two determiners control hereditary traits in pea plants. However, why are some peas wrinkled? In this investigation, we will explore the scientific principles that lead to peas becoming wrinkled.


This lab experience is separated into four investigative segments:

  1. Human saliva and enzymes

  2. Osmosis and Dialysis Tubing

  3. Analyzing dry and imbibed weights of wrinkled and smooth pea seeds

  4. Putting it All Together, What makes Wrinkled Peas?

Much Ado About Wrinkles Pupil Pagesummer 2017.docx (617 kB)
Wrinkling Student Pages