Enzymes A Levels Flashcards
What is the unique feature of enzymes that allows them to function?
Enzymes have a unique three-dimensional conformation with an active site.
What are the two main components of the active site of an enzyme?
- Substrate-binding site
- Catalytic site
What types of bonds hold the active site of an enzyme together?
- Hydrogen bonds
- Ionic bonds
- Disulfide bonds
- Hydrophobic interactions
How many amino acids typically form the active site of an enzyme?
3 to 12 amino acids from different parts of a single polypeptide chain.
What role does the substrate-binding site play in enzyme function?
It recognizes and binds to substrate, determining enzyme specificity.
What is the function of the catalytic site in an enzyme?
It catalyzes the reaction when the substrate is bound.
What is the significance of the three-dimensional structure of an enzyme?
It is essential for maintaining the active site and overall enzyme function.
What structural aspect of enzymes is crucial for their specificity?
The substrate-binding site, which consists of amino acid residues that recognize and bind to substrate.
What is required for the catalytic site to perform its function?
The substrate must be bound to the enzyme.
Other than the active site, what do other amino acids in an enzyme contribute to?
Maintaining the overall three-dimensional structure of the enzyme.
How do enzymes promote the formation of the transition state?
Through several mechanisms including:
* Allowing close proximity of reactants
* Ensuring correct orientation of reactants
* Destabilising the bonds of reactants
* Providing a conducive microenvironment
These mechanisms work together to increase the likelihood of a reaction occurring.
What role does temporary binding of substrates play in enzyme function?
It allows close proximity of reactants
This enhances the chances of reactants interacting and forming products.
What ensures the correct orientation of reactants in an enzymatic reaction?
The enzyme itself
Proper orientation is crucial for the reaction to take place effectively.
What happens to the bonds of reactants during the enzyme-catalyzed reaction?
They are destabilised
Enzymes contort reactant molecules to facilitate the formation of the transition state.
What is an example of a microenvironment provided by enzymes?
A water-free zone
This is often created by hydrophobic amino acids at the active site, allowing non-polar reactants to react more easily.
Fill in the blank: Enzymes create a _______ conducive for reaction.
Microenvironment
This microenvironment can enhance the reactivity of the substrates.
True or False: Enzymes can only catalyze reactions involving polar substrates.
False
Enzymes can facilitate reactions with non-polar substrates as well, especially in a suitable microenvironment.
Substrate concentration affecting rate of enzyme activity. High and low conc
At low substrate concentration,
- substrate conc in the limiting factor of the reaction
- so increase sub concentration leads to proportional increases rate of enzyme activity
- Rise in substrate conc increases frequency of effective collisions between enzymes and substrates
- Not all the active sites of the enzymes will be occupied at any 1 point in time
- so more enzyme-substrate complexes are formed per unit time
________________________
At high enzyme conc
- As sub conc continues to rise, rate of enzyme activity increases slightly
- all Active sites of the enzymes aresaturated with substrate
- Max number of enzyme substrate complexes formed per unit time
- Rate of enzyme activity reached max
- Other factors like enzyme concentration / temperature are now the limiting factors
Enzyme concentration affecting rate of enzyme activity. Low and high conc
At low enzyme conc
- Enzyme conc is limiting the rate of reaction
- increase in enzyme concentration, increases number of active sites so rate of enzyme activity increases proportionally
- FREQUENCY of Effective collisions between enzymes and substrate increases
- Number of enzyme-substrates complexes formed per unit time increases
- ____________________________
At high enzyme conc - IF SUBSTRATE is NOT in excess, When enzyme conc continues to increase, increase in rate of enzyme activity slows down
- Not enough substrate molecules to occupy all the active sites in the enzymes
- Max number of enzyme-substrate complexes formed per unit time
- Other factors like substrate conc/temp are now limiting the rate of reaction
Temp affecting the rate of reaction
____________________________
At optimum temp
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