Enzymes Flashcards
What are enzymes?
Enzymes are biological catalysts that accelerate chemical reactions in living organisms by lowering the activation energy needed for the reaction
What is the structure of an enzyme?
Enzymes are 3D Tertiary structured globular proteins
What does the active site of an enzyme consist of?
Consists of few amino acids
Whats special about enzyme substrate complex?
Enzymes are specific to the substrates so they bind, so only one type of substrate fits into the active site of an enzyme
What is the induced fit model?
The structure of the enzyme is altered so that the active site of the enzyme fits around the substrate
What factors affect the rate of enzyme controlled reaction?
Temperature
PH
Enzyme concentration
Concentration of NCRI
Concentration of CRI
How does temperature affect the rate of enzyme controlled reaction?
rate of reaction increases to optimum temperature as the kinetic energy increases of the enzyme increases. Above the optimum temperature of the reaction decreases as the enzyme denatures
How does PH affect the rate of enzyme controlled reaction?
It affects the enzymes shape as it can disrupt the hydrogen bonds in the tertiary structure of the enzyme. All enzymes work at different optimum PH
How does enzyme concentration affect rate of enzyme controlled reaction?
Rate of reaction increases as the enzyme conc increases as the concentration of active sites are higher so more substrates can bind to them and form enzyme substrate complexes, but at a point there will be no change as there would not be enough substrates to bind to the active site so substrates are a limiting factor
How does the conc of NCRI affect the rate of enzyme controlled reactions?
As the conc of ncri increases the rate of reaction decreases as the ncri changes the shape of the enzyme as it binds to the allosteric site. This means the substrate cannot bind to the active site as the shape has changed results in decreased rate
How does the conc of CRI affect the rate of enzyme controlled reactions?
As the concentration of CRI increase the rate of reaction decreases as the active sites are temporarily blocked by inhibitors so substrates cannot bind to them
What are cofactors?
A non protein substance
What are activators?
They are inorganic groups permanently bound to an enzyme and so are a type of prosthetic group e.g Fe,Cu,Zn
What are coenzymes?
They are organic molecules that bind only temporarily to an enzyme to allow the transfer of a chemical for a chemical reaction e.g Vitamin C and ATP
Why do enzymes increase rate?
Substrate molecules must collide with sufficient energy to alter the arrangement of their atoms to form products
The free energy of products must be lower than that of substrates
The activation energy of the reactions must be overcome
