Enzymes and Chemical Reactions Flashcards
exergonic
more energy released than absorbed
endergonic
more energy absorbed than released`
potential energy
energy stored in chemical bonds
kinetic energy
energy being used. movement, light, sound
activation energy
energy input needed to start a reaction
catalyst
a substance that speeds up reaction rates without being used up
catabolic
release energy by breaking up complex molecules
anabolic
uses energy to create complex molecules
how are enzymes biological catalysts
they are proteins that speeds up reaction rates in biological processes without being used up
metabolism
sum of organism’s chemical reactions
why are ender- and exer- gonic reactions often coupled
Because metabolism is the sum of these reactions
Transition State
The transition state is when the bonds between molecules are at their weakest due to the potential energy being highest.
what is an active site?
where the enzyme bonds with the substrate
what bonds help bond the enzyme and substrate?
Hydrogen bonds
Ionic bonds
Hydrophobic interactions
Covalent bonds
what are the 2 theories on how enzymes and substrates bond?
lock and key, and induced fit.
what is lock and key?
It is a theory that enzymes are built geometrically and chemically to fit a substrate.
what is induced fit?
It is a theory that an enzyme changes to fit the substrate
What factors affect if a substrate can bond with a enyme?
competitive inhibitors, non-competitive inhibitors, and a change in pH or heat.
How does substrate concentration affect enzyme reaction rates?
As substrate concentration increases, the reaction rate increases.
When the enzyme is saturated, the rxn rate will reach maximum.
It is saturated is when there are more substrates than enzymes.
How does enzyme concentration affect enzyme reaction rates?
As enzyme concentration increases, the reaction rate increases(assuming substrate is abundant).
As enzymes increase, there are more collisions between substrates and enzymes, increasing the likelihood that an enzyme will collide.
There are theoretically no limits to the rate of rxn when adding enzymes, but in the body, the substrate becomes the limiting factor.
How does temperature affect enzyme reaction rates?
As temperature increases, so does the rxn rate UNTIL the enzyme begins to unfold/denature. Every enzyme has an optimal temperature at which it works best. A Fever is created to denature bacteria when you are sick.
How does pH affect enzyme reaction rates?
Every enzyme also has an optimal pH. This optimum is usually the pH where the enzyme functions in nature. Most mammals function best at a pH of about 7-8, similar to cellular environments.
Mouth = fairly neutral
Stomach = highly acidic
Small intestine = fairly basic
What are cofactors and how do they affect enzyme reaction rates?
Many enzymes require the binding of smaller non-protein cofactors to function.Cofactors may be a small metal ion or vitamins.
How do inhibitors affect enzyme reaction rates?
Enzyme inhibitors are chemicals which bind to enzymes and decrease the enzyme’s ability to catalyze its reactants.
Usually reversible, or can be irreversibly (covalent)
