2.1.4 Enzymes COMPLETE Flashcards
Active Site
The intended area on the enzyme surface which has a complimentary shape to the substrate
Catalyst
A Chemical that speeds up rate of reaction but remains unchanged
Metabolism
Chemical reactions that take place in the living organisms
Substrate
The molecule that is altered by an enzyme catalysed reaction
DEFINITION- Enzyme
A globular protein with a specific shape that can act as a biological catalyst, speeding up metabolic reactions in living organisms
Turnover Number
The number of reactions that an enzyme molecule can catalyse per second
Intracellular Vs Extracellular
Intracellular work inside the cell catalysing reactions such as photosynthesis.
Example: Catalase
Extracellular work outside cells catalysing hydrolysis reactions that breakdown macromolecules
Example: Amylase & Trypsin
How enzymes work
They speed up metabolic reactions by acting like a catalyst. Make substrates into products when they randomly collide
Catabolic Reactions
Where substrates are broken down, strain is applied after the enzyme attaches so the molecule breaks apart.
Anabolic Reactions
Where substrates are joined to make a larger product, When the enzyme attaches repulsion is reduced so they bond more easily
Why enzymes are specific
The active site is specific for a reaction and the shape is maintained by the tertiary structure, therefore the enzyme only works with one molecule.
Activation Energy
The energy that is required to begin a chemical reaction
Enzymes decrease the Ea so reactions take place more easily
Lock and Key
The complimentary active site and substrate fit together like a lock and key
Induced Fit
The enzymes active site changes slightly upon collision making the active site fit closer to the substrate.
May also be changes to the amino acids in the active site that contributes to holding the substrate in place.
Temperature on rate of reaction
When heated kinetic energy increases so random collisions are more frequent, these also occur with more energy and greater force.
Therefore ROR increases
Optimum Temperature
The temperature that gives the enzymes the maximum rate of reaction. Its a balance between increasing kinetic energy of the molecules and not denaturing it
Temperature and Denaturation
When the tertiary structure I changed to the point where it no longer works, irreversible.
Molecules vibrate putting strain on the bonds, when the hydrogen and ionic bonds break the tertiary structure changes and ROR decreases
ROR calculation
=1/ Time taken to reach end point
Refers to temp increasing by 10 degrees
pH on Enzyme Reactions
H+ ions attach to negative charges and alter the active site. This is because they attach to the R groups in the amino chains and interfere with bonding.
Optimum pH
Where the concentration of H+ gives the tertiary structure the best complimentary shape
A very narrow range is expected as small changes make big differences
pH and Denaturation
Minor changes in pH do not denature enzymes as disrupted bonds reform. Denaturation only occurs with extreme pH away from the optimum
Affect of Substrate Conc.
More substrate increases the rate of successful collision
When it reaches max value all the active sites are full so no more affect
V Max is the maximum initial velocity of rate of the enzyme catalysed reaction
Affect of Enzyme Conc.
Increased enzyme conc. increases the ROR until all the substrates are full.
If both increased ROR consistently increases
Enzyme Synthesis
Depending on the cells needs, genes for synthesising particular enzymes can be switched on or off
