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What are cofactors and what role do they play in enzyme activity?
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Cofactors are non-protein parts that enzymes may need to function. They can be cations, organic molecules (coenzymes), or prosthetic groups.
How does pH affect enzyme activity?
pH affects the acidic and basic amino acids in the enzyme's active site. Extreme pH values can denature the enzyme, altering its structure and function.
How does substrate concentration affect enzyme activity up to a limit?
Higher substrate concentrations increase the reaction rate up to a saturation point, after which the rate no longer increases regardless of further substrate addition.
What is the effect of increasing enzyme concentration on the reaction rate?
Increasing enzyme concentration increases the reaction rate up to a certain limit, beyond which the reaction rate will no longer increase.
What is the optimal temperature for most human enzymes and what happens at higher temperatures?
The optimal temperature for most human enzymes is 37°C. Higher temperatures can denature enzymes, causing them to lose their functional shape.
What are prosthetic groups and how do they differ from coenzymes?
Prosthetic groups are non-protein components permanently bound to enzymes, while coenzymes are organic molecules that temporarily join the enzyme-substrate complex.
Explain the Induced Fit Hypothesis of enzyme action.
According to this model, the enzyme changes shape to bind the substrate more tightly once they interact.
What is the function of the active site on an enzyme?
The active site is the region where substrates bind and reactions occur, characterized by a specific arrangement of amino acids that make it unique to a specific substrate.
Describe the Lock and Key Hypothesis.
This model suggests that the substrate fits precisely into the enzyme's active site, much like a key fits into a specific lock.
What are enzymes and when were they discovered?
Enzymes are proteins or RNA that speed up biochemical reactions by modifying substrates. They were discovered by Anselme Payen in 1833.
Why are enzymes known for their specificity?
Enzymes are specific because their active sites have a unique arrangement of amino acids that only fit particular substrates.
How do enzymes speed up chemical reactions in the human body?
Enzymes lower the activation energy required for reactions to start, facilitating the binding and modification of substrates at their active sites.
What are competitive inhibitors and how do they affect enzyme activity?
Competitive inhibitors block the active site of the enzyme, preventing substrates from binding and thus inhibiting the enzyme's activity.
Define non-competitive inhibitors and their mode of action.
Non-competitive inhibitors bind to a different part of the enzyme, causing a shape change that distorts the active site and inhibits enzyme activity.
Differentiate between a holoenzyme and an apoenzyme.
A holoenzyme is an active enzyme with its coenzyme, while an apoenzyme is an inactive enzyme without its coenzyme.
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