What are enzymes made of?
Globular proteins.
Why do enzymes have hydrophilic R groups on their surface?
To ensure they are soluble in water.
What is the active site of an enzyme?
The region where the substrate binds.
What does the induced fit hypothesis describe?
Enzymes and substrates change shape slightly to ensure a perfect fit.
What happens to enzymes after catalyzing a reaction?
They remain unchanged.
What is a substrate?
The molecule that binds to the enzyme’s active site.
What is an enzyme-substrate complex?
The temporary structure formed when a substrate binds to an enzyme.
How do enzymes lower activation energy?
By holding substrates in a position that facilitates reaction.
What happens to the bacterial cell wall when lysozyme acts on it?
It loses rigidity and the cell bursts.
What type of reaction does lysozyme catalyze?
Hydrolysis.
What determines an enzyme’s specificity?
The shape of its active site.
What is activation energy?
Energy required to start a chemical reaction.
What is the effect of low temperature on enzymes?
Slower movement of molecules
=> Smaller KE
=> Less collisionsions with active site
=> Slower reaction rates.
What happens to enzymes above their optimal temperature?
They denature
=> Loses functions.
What does denaturation mean?
Loss of enzyme shape and function.
How does pH affect enzymes?
Alters the ionic bonds
=> Change 3D structure of enzymes.
What happens to enzymes at extreme pH levels?
They denature.
How does substrate concentration affect reaction rate initially?
The rate increases with substrate concentration.
Molecules more chance to interact with active site
What happens when enzymes are saturated with substrate?
The reaction rate plateaus.
Why does the reaction rates plateau when substrate concentration increase indefinitely?
Enzymes reached max rate, all enzymes are linked to molecules
=> Add more won’t help
What is competitive inhibition?
An inhibitor competes with the substrate for the active site.
What are competitive inhibitors?
Molecules with similar shape to enzyme’s substrate.
Can competitive inhibition be reversed?
Yes, by increasing substrate concentration to compete again.
Can competitive inhibition stop all reactions?
Competitive inhibitors can’t compete with all, substrate can still bind to active site.
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Chapter 1: Cell Structure168
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Chapter 2: Molecular Biology107
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Chapter 3: Cell Membrane77
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Chapter 4: Enzymes46
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Chapter 5: Cell Cycle and Cell Division121
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Chapter 6: Nucleic Acid. The Central Dogma168
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Chapter 7: Energy and Cell Respiration145
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Chapter 8: Photosynthesis51
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Chapter 9: Genetics and Inheritance226
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Chapter 10: Natural Selection. Evolution161
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Chapter 11: Biotechnology69
