Enzymes Flashcards
What are enzymes?
Proteins that function as organic catalysts without being used up in the process.
What do enzymes do?
Lower activation energy needed to undergo chemical reactions, can have catabolic and anabolic functions.
What is the active site?
The site where an enzyme binds to its substrate, complementary to the shape of the substrate.
What is the Lock & Key Model?
Shape of enzyme (the key) is complementary to the shape of the substrate (the lock).
What is the Induced Fit Model?
When the enzyme and substrate join, the active site will slightly change to fit exactly.
How can rates of catalysis be increased?
increasing ** molecular motion** of particles → increased kinetic energy via higher temp
increasing concentration of particles
both leads to more collisions
What is denaturing of proteins?
enzymes denature when they are outside their optimum pH or temp
pH - this alters charge of enzyme that overall changes it’s shape
higher temp - changes hydrogen bonds
can no longer bind to it’s specific substrate
What factors affect enzyme activity?
Enzyme concentration, substrate concentration, temperature, optimum pH, cofactors and coenzymes, enzyme inhibitors.
What are cofactors?
Typically metal ions or non-protein molecules (e.g., iron).
What are coenzymes?
Non-protein organic molecules (e.g., vitamins).
What are enzyme inhibitors?
Substances that slow or stop an enzyme’s activity (e.g., penicillin).
What is the optimum pH in different parts of the body?
Stomach = 2 (pepsin), mouth = 7 (amylase), intestine = 7-9.
What is the optimum temperature for enzymes?
Around 37ºC.
At what temperature does an enzyme start to denature?
Past 37ºC.
How do low temperatures affect enzyme activity?
Insufficient thermal energy reduces kinetic energy, leading to fewer collisions.
What is saturation?
Occurs when there are more substrates than enzymes, causing the rate of activity to plateau.
Why must products be continually removed?
Otherwise, the rate of reaction will slow due to difficulty in collisions.
What is a substrate?
A molecule upon which an enzyme acts.
What do cofactors & coenzymes do?
Change the shape of the active site so the enzyme can combine with the substrate
