Topic 1- Key Concepts in Biology Flashcards
What do living cells do?
Carry out a huge number of chemical reactions
Are chemical reactions normally slow or fast?
Slow
What are some problems with using the temperature to speed up reactions?
- require a lot of energy
- can damage cells
- speed up non-useful reactions
What is a better way to speed up a reaction?
Catalyst
Define catalyst
A substance that increases the speed of a reaction without being changed or used up in the process.
Define enzyme
A biological catalyst made by living organisms
What are enzymes called and what are they made out of?
Enzymes are large proteins made out of amino acids which can form different shapes which are unique enzymes.
What do chemical reactions involve?
- Taking a reactant (substrate) and Breaking it into smaller pieces (product)
- Joining multiple substrates into a single product
Define active site
It’s the part of the enzyme where it joins on to its substrate to catalyse the reaction
What happens if the enzyme can’t fit into its active site and why are they specific about the reactions they speed up?
The reaction wouldn’t be catalysed which is why the specific about which reactions they speed up
What is the lock and key model?
Scientist thought that the substrate had to fit perfectly into the active site like key into a lock.
What is the induced fit model?
The enzyme actually changes shape slightly as it binds to the substrate so they can fit together more perfectly.
The active site is complimentary to the substrate.
What two factor affect an enzyme?
Temperature & pH
How temperature affect the rate of reaction?
-As temp increase so does the rate of reaction
-After optimum temp rate drops rapidly
bc high temps brakes the bonds holding the enzyme together, active changes shape
-If active site changes too much enzyme won’t bind the substrate & catalyse the reaction = enzyme denatured
How pH affect the rate of reaction?
-If pH is too high or low it lowers the rate of the reaction
bc enzymes bonds start to break = active site changing shape
- At first there’s a small change so substrate can fit but not quite as well (it slows down ROR but doesn’t stop it)
- soon the active site changes so much the substrate can’t fit into enzyme is (denatured)
