ENZYME ACTION Flashcards
(20 cards)
What are enzymes
globular proteins that act as biological catalysts for metabolic reactions
Can enzymes be re-used?
yes
What is a catalyst
substance that speeds up a chemical reaction without being used in the reaction itself
What 2 types can enzyme action be
intracellular or extracellular
What is intracellular
inside cells
What is extracellular
outside cells
Where do substrates bind to on enzymes
active site
Can the active site change shape
yes
Why are enzymes highly specific
due to their tertiary structure
How do enzymes act as catalysts
lowering activation energy
What is the activation energy
the minimum energy that reactions require before the reaction can start
How does enzymes lowering activation energy mean reactions happen quicker and give and examples
they allow the reactions to take place at a lower temperature (e.g. metabolic reactions can occur rapidly at human body temp.)
How 2 ways do enzymes lower activation energy
by forming an enzyme substrate complex, which:
1) means the substrates are held close together so repulsion between them is reduced and therefore can bond easier
2) puts a strain on the bonds in the substrate so it can be broken up easier
How many models of enzyme substrate complex are there
2
What are the models of enzyme substrate complex
lock and key , induced fit
What is the lock and key model
each enzyme has a specific action site that fits a specific substrate exactly
What is a limitation of the lock and key model
other molecules could bind to enzymes at other sites which altered the shape of the active site, meaning the active site was flexible
What is the induced fit model
the active site forms as the enzyme and substrate interact, so the active site changes shape to fit around the substrate, which puts a strain on the bonds in the substrate. This lowers the activation energy
What is the active site shape determines by
tertiary structure
Which 3 ways can the tertiary structure be altered
changes in pH, changes in temperature, mutation in gene in primary structure
