5: Enzymes Flashcards
Catalyst definition
substance that increases the rate of a chemical reaction and is not changed by the reaction
Enzyme definition
proteins that function as biological catalysts
speed up the rate of metabolic reactions
Why are enzymes important in all living organisms?
speed up the rate of metabolic reactions
without - would take too long to occur
(so we will probably die :D)
Enzyme action
Lock and key hypothesis
- Substrate that fits the specific active site of enzyme binds to create an ENZYME-SUBSTRATE COMPLEX
- reaction occurs (catalysed by the enzyme)
- products released
Enzyme specificity
Each enzyme is complementary to only 1 type of substrate
has an active site - sequence of amino acids with specific shape that fit specific substrate
Factors that affect the rate of an enzyme-controlled reaction (4)
- temperature
- pH
- substrate concentration
- enzyme concentration
effect of temp on enzymes
above opt temp?
↑ temp = ↑ rate
until opt temp, particles have more KE - move faster = more successful collisions occur - more enzyme-substrate complexes formed
above optimum temperature:
enzymes DENATURE
active site distorted - heat breaks bonds that hold enzyme together
no longer fits the substrate- no enzyme-substrate complex can be formed (no reaction)
effect of pH on enzymes
above opt pH?
opt pH = highest rate
pH is too ↑ or ↓ = rate ↓
enzymes DENATURE - active site distorted, no longer fits the substrate