Energy & Molecular Interactions Flashcards
What is Energy?
ability to do work or cause change
What is Bioenergetics?
the study of energy in living organisms
What is Kinetic Energy?
energy of motion
What is Potential Energy?
stored energy
The First and Second Law of Thermodynamics
1st Law: Energy is neither created or destroyed. It is only transferrable or convertible.
2nd Law: The entropy of a system is increased. (hotter object to a cold object) –> to increase randomness and disorder
What is Gibbs Free Energy?
It’s “available” energy which is used to do work or capture chemical bonds
What variables affect Gibbs Free Energy?
Enthalpy (total energy of a closed system)
Entropy (order of system)
Temperature
Endergonic Reaction
it is a required investment of energy –> a non spontaneous reaction or anabolic –> Positive G
Exergonic Reaction
a release of energy –> a spontaneous reaction or catabolic –> Negative G
How does a catalyst increase the rate of a chemical reaction?
by lowering the activation energy
Ligand
A substrate (or small molecules that bind)
Substrate
a reactant
Define Induced Fit
When the active sites changes its shape for the substrates to fit/bind
What is Specificity?
when substrate(s) bind to a specific target
High Specificity: One other molecule
Low: Many other molecules
What is Affinity?
the tightness/measure of strength in which a substrate binds to an enzyme or other types of proteins
- the binding is reversible
What is Potency?
the amount of substrate needed to produce a certain effect.
- for example, EC50, can be used to compare the POTENCY of substrates that reach 50% of the maximum response better.
What is Efficacy?
the capacity in which the response from a substrate can produce. (Maximum effect)
What is Kd?
it is used to compare affinities
What is Vmax?
The rate of product when enzyme become saturated by substrate
What is EC50?
a concentration of substrate where enzyme reaches 50% Vmax.
- compares potency of substrate
What is Saturation?
It is the point of no change in chemical reaction even after adding additional substrates.
Define Competitive Antagonist
prevent AGONISTS from binding –> physically blocking the binding site
Define Cofactor
metal ions –> help form the active site through a conformational change of the enzyme or help in enzyme-substrate binding.
Define Coenzyme
organic molecules derived from water-soluble vitamins –> transport hydrogen atoms and other small molecules between enzymes
Define Allosteric Antagonist
“inhibitors” that attach to the allosteric site of the enzyme/protein, and alter the shape of the binding site to NOT allow a substrate to bind to the enzyme.
Define Allosteric Agonist
“activators” that attach to the allosteric site of the enzyme, and alter the active site for the substrate to fit and bind –> enhance function.
How do cells regulate protein activity?
- Temp. and pH
- Concentration of cofactors, coenzymes, and enzymes
- Covalent modification of the protein
- Location of the enzyme
- Allosteric Antagonists and allosteric agonists
Define Phosphorylation
Define Kinase
attach a phosphate to a protein
Define dephosphorylation
Define Phosphatase
remove a phosphate from a protein
Define Proteolysis
Explain how and why temperature and pH can affect protein function.
The optimal temperature is 37 degrees celcius
The optimal pH is 7.4
- Ex. immune system works better at a slightly higher temperature, if too much, protein denatures.
- ex. Digestive enzymes work best at differing pH, it can be reversible, but if it’s obscure, then it becomes irreversible
Prevents protein from denaturing
