2007-01-29 00:06:23 · 4 answers · asked by sweetgurl_16 1 in Science & Mathematics ➔ Chemistry
Lactose is made of one galactose and one glucose unit.
Sucrose is made of one glucose and one fructose unit.
The bond and molecules they are composed of are different. Yeast can only break down the sucrose bond and is unable to break the lactose bond. This is due to the specificity of enzymes to act on certain substrates. Even the orientation of the bond is taken into account. Take cellulose and maltose for example:
Both are made of repeating glucose monomers linked together, maltose is easily digested, and we know cellulose, found in grass, is impossible to digest for us. What makes them different is the orientation of the bond, and that makes a hell of a difference for our digestive system and their enzymes.
2007-01-29 00:31:43 · answer #1 · answered by Anonymous · 0⤊ 0⤋
lactose can be directly fermented by heating,as in milk
but sucrose cant so a enzyme catalyst is used i.e. yeast
2007-01-29 01:50:47 · answer #2 · answered by john d 1 · 0⤊ 0⤋
coz lactose is resistant to yeast, while sucrose is not.
2007-01-29 00:13:58 · answer #3 · answered by Anonymous · 0⤊ 0⤋