Topic 3B:Biological molecules(enzymes)-Part 1 Flashcards
Define enzymes
enzymes are proteins that function as biological catalysts by speeding up the rate of chemical reactions.They remain chemically unchanged at the end of the reaction.
what is the function of enzymes ?
enzymes are biological catalysts which increase the rate of chemical reactions by lowering the activation energy required for the chemical reaction.
what are the 2 types of enzyme chemical reactions and define them
Anabolic reactions: forming larger molecules from smaller ones
Catabolic reactions:Breaking down larger molecules into smaller ones
what are the characteristics of enzymes?
1.speed up chemical reactions by lowering the activation energy needed to start the reaction
2.They can be reused as they are chemically unchanged at the end of each reaction
3.Specific in nature.Each type of enzyme can only act on one specific type of substance(substrate),because enzymes have a specific three-dimensional shape AND only substrate with shapes complementary to the shape of the active site can bind to it.
4.Enzymes are affected by temperature and pH.Temp and pH affects how each type of enzyme functions.The best conditions are optimal temperature and pH
what happens to enzymes when temperature is lower than optimal ?
.The enzymes become “frozen” and is temporarily not functional
Because:
.Kinetic energy of molecules is low
.Rate of effective collisions between enzymes and substrates is low
HOWEVER,active site of enzymes is still functional
what happens when temperature is higher than optimal OR pH is lower or higher than optimal ?
The enzymes become denatured,they are no longer functional
because:
.active site of enzymes is altered
.shape of active site no longer complementary to substrate
Define denaturation
It is the change in three-dimensional structure of an enzyme caused by heat or chemicals such as acids or alkalis.
