B.I.
center Genotype and Phenotype

Genetic Trait
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A Genetic Trait
The red color seen in these flowers, is ...
... an example of a genetic trait. Traits are small parts of the phenotype of an organism, such as the red color seen in the flower petals.

Under the magnifying power of a microscope, the flower petal cells can be seen to contain red granular material that is absorbing the rays of white light and only reflecting the "red" wavelengths. That is why the flower petals look red to our eyes.

Using a microscope with greater magnifying power, such as an electron microscope, it can be seen that the petal cells are packed with pigment granules, but the observer cannot see where these granules are coming from.

It takes the tools of molecular and cellular biology to see that, in the cytoplasm of the cell, a chemical reaction is taking place in which a colorless molecule is being converted into a red pigment molecule As with all chemical reactions within cells, this conversion reaction is catalyzed by an enzyme catalyst. Without this enzyme catalyst, the reaction would proceed so slowly that little or no pigment would be produced.

The enzyme catalyst makes the chemical reaction proceed at "life speed".

When the enzyme is present in the cell it can produce a lot of pigment and pigment granules. As these granules accumulate in the cells the flower petals turn red - the genetic trait.
The "red" trait, therefore is the product of a chemical reaction catalyzed by the enzyme.

Almost all enzymes are proteins.

Almost all traits are produced by the action of proteins.


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Science at a Distance
© 1997, 1998, 1999, 2000 Professor John Blamire