Enzymes Flashcards
What are enzymes?
They catalyse a reaction by increasing the rate of reaction and lowering the activation energy.
They are 3-D tertiary structured globular proteins whose shape is determined by the primary sequence of amino acids.
What is the active side of an enzyme?
An area of the enzyme that is made up of only a few amino acids and forms a small depression in the overall enzyme.
What is the molecule that the enzyme act upon called?
Substrate
Explain the specificity of enzymes.
Enzymes are specific to substrates, meaning that only one type of substrate fits into the active side of the enzyme when the enzyme and substrate find they form an enzyme substrate complex.
What is the induced fit model?
The structure of the enzyme is altered so that the active side of the enzyme fits around the substrate.
What are the six factors affecting the rate of enzyme controlled reactions?
Temperature
PH
Enzyme concentration
Substrate concentration
Concentration of competitive inhibitors
Concentration of non-competitive inhibitors
Explain why temperature affects the rate of enzyme controlled reactions.
Rate of reaction increases up to the optimum temperature as the kinetic energy of the enzyme increases. Above the optimum temperature rate of reaction decreases beyond the optimum temperature as the enzyme becomes denatured.
How can pH affect the rate of enzyme controlled reactions?
The pH of a solution is a measure of the hydrogen ion concentration. PH affects the enzymes shape as it can disrupt the bonds in the structure of the enzyme like temperature all enzymes work at different optimum pH’s.
How can enzyme concentration affect the rate of enzyme controlled reactions?
The rate of reaction increases as enzyme concentration increases as there are more active sites for substrates to bind to however increasing the enzyme concentration beyond a certain point has no effect on the rate of reaction as there are more active sites than substrates so substrate concentration becomes the limiting factor.
How can substrate concentration affect the rate of enzyme controlled reactions?
As concentration of substrate increases rate of reaction increases as more enzyme substrate complexes are formed however beyond a certain point the rate of reaction no longer increases as enzyme concentration becomes the limiting factor.
How can concentration of competitive inhibitors affect the rate of enzyme controlled reactions?
As concentration of competitive inhibitors increases rate of reaction decreases as the active site are temporary blocked by inhibitors so substrates cannot bind into them.
How can concentration of non-competitive inhibitors affect the rate of enzyme controlled reactions?
As concentration of non-competitive inhibitors increases rate of reaction decreases as the shape of the enzyme is altered by the inhibitors and so the substrate cannot fit.
