4.1 Enzyme Action Flashcards
What are enzymes? What do they do?
Enzymes are biological catalysts, (globular proteins) that interact with substrate molecules, increasing the rate of reaction
What is metabolism?
Sum of all reaction pathways occurring in an organism
What factors affect the rate of cellular (chemical) reactions?
Temperature, pressure, pH
What is the Vmax
The point up to which enzymes can increase the rate of reaction
What is the specificity of an enzyme?
The concept that each enzyme can catalyse only one biochemical reaction
What is activation energy?
Amount of energy needed to start a reaction
What is the active site?
An area within tertiary structure of enzyme with complementary shape to a specific substrate molecule
What is the idea behind the lock and key hypothesis?
Only a specific substrate will fit into the active site of an enzyme
What do you call it when a substrate is bound to the enzyme’s active site?
Enzyme-substrate complex
What is the enzyme-substrate complex?
When the substrate is bound to its complementary active site
What is an enzyme-product complex?
Formed when substrates react, and the products are formed in an enzyme-product complex
What are the stages in the lock and key hypothesis?
- Substrate binds to complementary active site, forming enzyme-substrate complex
- Substrate reacts and products are formed in enzyme-product complex
- Products are released, leaving enzyme unchanged
What is the idea behind the induced-fit hypothesis?
Enzyme’s active site changes shape as the substrate enters
Where do intracellular enzymes react?
Inside cells
Where is catalase found?
Plant and animal tissues
What is the role of catalase?
H peroxide is a toxic product of metabolic pathways; catalase ensures it’s broken down to O2 + H20 quickly, preventing its accumulation
Where do extracellular enzymes react?
Outside of the cells that made them
State the name of 2 extracellular enzymes involved in human digestion
Amylase, trypsin
Where does the digestion of starch occur?
Digestion of starch begins in mouth and continues in small intestine
What are the 2 steps in the digestion of starch?
- Starch polymers are partially broken down into maltose, a disaccharide, catalysed by amylase
- Maltose is broken down into glucose, a monosaccharide, catalysed by maltase
Where is amylase produced?
Salivary glands and pancreas
Where is amylase released after being produced?
Saliva or pancreatic juice into small instestine
Where is maltase found?
In small intestine
What is type of enzyme is trypsin? What is its function?
Protease - catalyses digestion of proteins into smaller peptides, which are broken down into amino acids
