Enzymes 1
The place where substrates bind to.
Active site.
How enzymes speed up reactions.
Enzymes hold the two substrates together long enough for the reaction to take place.
Give four examples of enzymes in this course.
Catalase, trypsin, pepsinogen, ligase, RNA polymerase, maltase, etc.
List three denaturing factors.
List three regulatory factors.
Change in concentration of enzyme or substrate, presence of inhibitors.
The equation for an enzyme-catalzyed reaction is:
E + S -> ES -> E + P.
Cells are constantly converting chemicals from one form to another to maintain_____.
Homeostasis.
Metabolic pathways consist of only one reaction and one enzyme. True or false?
False. While simple pathways can have just one enzyme, many pathways are more complex and have many steps.
What does it mean for an enzyme to denature?
A denatured enzyme has lost its shape and therefore its function.
Increasing the concentration of substrate does not always leads to an increase in reaction rate. True or false.
True. Does not increase rate further if there is too much substrate for a constant amount of enzyme.
Enzymes need steroids and buffers to work properly. True or false?
False. Enzymes need vitamins and minerals to act as co-enzymes and co-factors to help form the ES complex.
Thyroxin treatment can be used to stimulate weight loss in some people by:
Increases the metabolic rate; increases body's usage of energy reserves(more cellular respiration).
Explain how complex metabolic pathways self-regulate.
The final product acts as a non-competitive inhibitor to the first enzyme. Negative feedback loop.
A temperature too low or too high will completely stop an enzymes ability to function. True or false.
False. While a very high temperature will eliminate an enzyme's function, lowering it will only slow the enzyme down.
The site that a non-competitive inhibitor will bind to.
The allosteric site.
Explain the lock and key model.
The enzyme (key) unlocks the substrate (lock) and to form the products. Fit each other perfectly, enzyme does not change shape.
Explain the induced fit model.
The enzyme undergoes a slight conformational change to fit the substrate and resumes its original shape after forming a product.
Why would drugs like penicillin destroy bacteria but have no effect on human cells?
Penicillin would fit the active site of only bacterial enzymes.
Normal operating temperature and pH.
The general optimal temperature is 37*C, but there is no normal pH; different enzymes need different pH.
How does the presence of a heavy metal influence enzyme activity?
A heavy metal (ex. Lead Pb2+ or Mercury Hg2+) poisons the enzyme by binding irreversibly to it.