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Biological reactions are regulated by enzymes - Coggle Diagram
Biological reactions are regulated by enzymes
Enzymes
Globular proteins
Tertiary structure
Intra + Extra, Cellular
Active site
Specific shape
Determined by sequence of amino acids in polypeptide
Enzyme + substrate = enzyme substrate complex
Enzyme + substrate must collide successfully, binding by interactions of R groups
Activation energy - The energy required to perform a reaction
Energy is needed to break pre-existing bonds, energy is also released when bonds are made
Biological catalyst
5 Factors affect rate of reaction
Enzyme
At low enzyme conc. all active sites occupied
At high enzyme conc. substrates are limiting factor, no more substrates available
Substrate
At low substrate conc. not all active sites occupied
At high substrate conc. enzymes are limiting factor, all active sites occupied
Temperature
Increases successful collisions
More kinetic energy
Optimum - The highest rate of reaction
Product used quickest
Maximum number of enzyme - substrate complexes are formed at the same time
Test
Milk
Sodium bicarbonate added
Lipase
Pink > Clear
Denatured - Bonds vibrate + break, leading to the active site denaturing
Loss of secondary + tertiary structure
pH
Amino acids have basic + acidic groups
Small changes = inactivation
Large changes = denaturation
Optimum = greatest freq. of e-s complex formations
Inhibitors (information at bottom)
Theories
Lock and key
Active site is lock
Substrate is key
Fixed shape
Complimentary shape
Induced fit
Shape of active site changes, + stronger bonds formed, weakening the bond in substrate, lowering activation energy
As substrate enters the active site, forces of attraction between the substrate + R groups of the amino acids in the active site are formed
Lysozyme
-Bolic Enzymes
Anabolic enzymes
Builds a larger molecule
Monomers break down into 2+ parts
Anabolic - Build
Catabolic enzymes
Standard enzymes
Breaks down a large molecule
2+ monomers
Inhibitors
Competitive
Similar shape to substrate
Temporary + reversible
As substrate conc. increases, effect of inhibitor decreases
Non-competitive
Bind to allosteric site
No resemblance to substrate
Active site structure is changed
Can be reversible, mostly non-reversible
Cannot get back to maximum rate of reaction by increasing substrate
Variables
independant
pH
temperature
Substrate
Enzyme
dependant
Time
Mass
Absorbance
Volume
Immobilised enzymes
Beads
In inert (Non reactive) substances
Gel membrane
Alginate
Polythene
Stabilises enzymes
less change to Temp. + pH
Advantages
Recovered + reused
Small amounts of enzyme required
Enzyme doesn't contaminate product
Multiple enzymes acting on one substrate
Lower / higher temp. can be used + give higher yields than free enzymes
used in industry
used in biosensors
Net