Chapter 4 ~ Enzymes, Metabolism, and Cellular Respiration

-Why do we eat….energy + nutrients + challenge (eating the things you need in nutritious ways but you need a BALANCE to get that proper weight)

-chemical reactions are important to keep the body functioning properly

-how do reactions get started? a + b  c + d reactants  products
-reactants must absorb some energy
-the energy barrier prevents molecules from breaking down spontaneously (the energy activation : EA)
-you add heat to reach that energy level -heat is non-specific…cells like control

Enzymes and Metabolism
-enzymes are proteins (protein structure is important)
-catalyst : increases the rate of chemical reactions -doesn’t get used up in the reaction (same at the beginning + end)
-how?...lower the activation energy (lowers that barriers)
-how do enzymes work? -enzymes are selective
-nucleus gets the message that the cell needs a certain enzyme, the protein is made through RNA from the DNA -a specific enzyme catalyzes each cellular reaction
-think of the clip : a certain shape of an enzyme can only fit with a certain active site
-induced fit : changing shape together to fit in with each other
-substrates & enzymes & active sites -determines which chemical reactions occur in a cell

Enzymes and Health
-lactose intolerance (inability to digest the sugar lactose)
-PKU : phenylketonuria -this enzyme does not transform into tyrosine
-mutation in gene for enzyme phenylalanine hydroxylase -brain damage is caused by a build up
-treatment/prevention
-screening all newborns (take-home test) -dietary