8: Soybeans, George Washington Carver, Nitrogen fixation, Fabaceae, Tofu, Soy sauce, Forage crops Flashcards
What soil bacteria form a symbiotic relationship with legumes like soybeans?
Rhizobium bacteria.
What benefit do Rhizobium bacteria provide to the plant?
They fix atmospheric nitrogen (N₂) into ammonia (NH₃) for plant use.
What does the plant provide to the bacteria in return?
Carbohydrates produced via photosynthesis.
Where in the plant does this symbiosis occur?
In root nodules.
What is nitrogen fixation?
The conversion of atmospheric nitrogen (N₂) into ammonia (NH₃).
List 3 natural ways nitrogen fixation occurs.
Symbiotic bacteria,
free-living bacteria,
lightning.
What industrial process is used for nitrogen fixation?
The Haber-Bosch process.
Why are soybeans considered hard to digest?
They contain indigestible oligosaccharides and anti-nutritional compounds.
Name two oligosaccharides in soybeans that cause gas.
Stachyose and raffinose.
What is the role of trypsin inhibitors in soybeans?
They block trypsin, reducing protein digestion
What does phytic acid do in the digestive system?
Binds to minerals and lowers their absorption.
Where was the soybean domesticated?
Yellow River Valley, China.
From which wild species was soybean domesticated?
Glycine soja
Name 3 traits selected during soybean domestication.
Bushy growth,
larger seeds,
uniform colour and size.
What are the main steps in tofu production?
Soak → blend → boil → filter → add coagulant → press curds → cool.
What does a coagulant like nigari do in tofu making?
Causes soy proteins to curdle and form solid curds.
What are the solid and liquid products of tofu production?
Curds (tofu) and whey (liquid).
What microorganism is used in the first step of soy sauce production?
Aspergillus (used to make Koji).
What other microbes are involved in soy sauce fermentation?
Lactic acid bacteria and yeast.
Why is salt added during soy sauce production?
To prevent spoilage and enhance flavour.
What is geocarpy?
A reproductive process where fruit develops underground.
How do peanuts exhibit geocarpy?
After fertilization, a peg pushes the developing fruit into the soil.
List three non-food uses of soybeans.
Biodiesel, bioplastics, and animal feed (soybean meal).
What is fermentation (in soy processing)?
Anaerobic breakdown of molecules using organic electron acceptors.
