Enzymes C1.1 Flashcards
Enzymes are what?
catalysts
What is rate of reaction?
amount of product produced prr unit time. the speed at which a reaction is taking place.
Substrate
reactant being changed in the reaction
Active site
bonding site on the enzyme is here reaction takes place
Enzyme-substrate complex
structure being formed during the reaction when being bond together. (temporary association)
What is metabolism?
complex network of interdependent and interacting biochemical reactions occurring in living organisms.
The types of metabolic reactions
catabolic and anabolic
What is an anabolic reaction?
building of molecules. energy required. condensation. water released
What is a catabolic reaction?
breaking of molecules. energy released. hydrolysis. water needed
Examples of anabolic reactions
protein synthesis, DNA synthesis during replication, photosynthesis, synthesis of complex carbohydrates
Examples of catabolic reactions
digestion of food, cell respiration (oxidation of glucose/lipids to carbon dioxide and water), decomposition of complex carbon compounds in dead organic matter
What is a globular protein?
spherical in shape and are water soluble.
- composed of few amino acids but interactions between amino acids in the structure ensure that active site has necessary properties for catalysis.
enzymes are globular proteins
What is enzyme-substrate specificity
highly specific and the induced shape change upon binding results in proper alignment of the catalytic groups.
Induced-fit model of the enzyme process
both enzyme and substrate can change shape to fit one another. switches back after
Molecular motion of enzymes and substrates
movement is needed for the substrate and active site to come together and COLLIDE.
How does the molecular motion of enzymes and substrates in a solution affect it?
greater kinetic energy = greater chance of collision.
Immobilized enzymes
unable to move and embedded and immobilized into a membrane. substrate need to do the moving
How is immobilized enzymes used and how does it work?
cell-free preparations industrially for lactose-free milk.
enzymes attached to an insoluble material or membrane with the substrate moving toward it
The formation of enzyme-substrate complex depends on…
molecular motion, correct alignments, and speed of movement.
How does molecular motion affect the formation of E-SC?
molecular motion cause random collisions between enzymes and substrates. (due to aqueous solution allowing them to move freely)
How does correct alignment and angle affect the formation of E-SC?
the correct alignment and angle between the enzyme and the substrate affect the SUCESS of the collision.
How does speed of movement affect the formation of E-SC?
depending on their molecular size… substrates are usually smaller than enzymes and move faster than them
How can enzyme activity be affected?
temperature and pH
How does temperature affect enzyme activity?
high temperature causes denaturation of the enzyme (protein).
Why does temperature affect enzyme activity?
increase in temperature causes vibrations within the molecule and that causes extra energy to end up breaking intra-molecular bonds within the protein.
Other than denaturation, how does temperature affect enzyme activity?
increase in temp can also increase the rate of reaction due to molecules having more kinetic energy (increase the chances of collision, molecular motion)
Why can temperature denature or increase enzyme activity?
when solution is heated ABOVE optimum, chance to break bonds increase bc it can not absorb anymore heat.
What is optimum temperature?
the temp at which activity of any process is most affective
How does pH affect enzyme activity?
pH is a measure for the number of hydrogen ions are in a solution.
What does pH tell about the number of hydrogen ions?
lower pH = higher hydrogen ions
pH is logarithmic, therefore change in pH by one unit = tenfold rise in hydrogen ions
What does it mean for pH to affect enzyme activity?
pH above or below the optimum (acidic or alkaline) the structure of enzyme becomes denatured and changed (reversible)
How doe substrate concentration affect enzyme activity?
increase substrate = increased rate of reaction, bc the changes of successful molecular collisions is increased
at optimum, all active sites are full and max efficiency.
however, anywhere above will do no effect
What is the effect of enzymes on activation energy?
enzymes allow reactions to be carried out at lower activation energy.
(more reactions carried out and increased rate of reaction)
What is activation energy?
the minimum energy needed for a chemical reaction to occur.
How do enzymes decrease activation energy needed?
by weakening bonds.
after products are formed energy is released
Why do reactions need activation energy?
need to reach a transition state before completing
What is the transition state?
intermediate state before being converted into products. bonds need to be broken and need energy
The uses of enzymes in industry
more than 500 immobilized enzymes have commercial uses
Examples of uses of enzymes in industry
medicine and biotech, brewing, and detergents
Medicine and biotech enzymes
contact lens cleaners (remove proteins avoid bacteria), genetic engineering for PCR and polymerase
Brewing enzymes
clarification of beer
Detergents enzymes
proteases and lipases to break down proteins and fat stains
How is enzyme-catalyzed reactions measured?
amount of substrate that has disappeared OR amount of product accumulated IN A UNIT OF TIME
What does the graph of enzyme-catalyzed reactions tell?
the rate of reaction is not constant during reaction.
fast at first but slows down as reaction proceeds.
What is the instantaneous rate of reaction?
measured by drawing a tangent to the curve at the specified time.
change in p / change in t
Initial rate of reaction
When the instantaneous rate of reaction is at t=0.
