unit 1 week 3 info Flashcards
How did Buchner show that fermentation doesn’t require yeast cells?
Fermentation requires enzymes.
What are enzymes?
Enzymes are proteins and are the general term for protein catalysts, while ribozymes are the general term for RNA catalysts.
What are the properties of enzymes?
Enzymes are only required in small amounts; each enzyme can repeatedly participate in a reaction because they’re not altered during the reaction; enzymes have no effect on the thermodynamics of the reaction.
What do enzymes do?
Enzymes accelerate the rate of reaction.
What is the difference between enzymes and other catalysts?
Enzymes increase the velocity of a reaction while catalysts just accelerate it; enzymes have specificity in reactants and can regulate activity to meet the cell’s needs.
What do chemical transformations require?
Certain covalent bonds within reactants to be broken.
What is activation energy?
The energy required for reactants to undergo a chemical transformation.
How do enzymes catalyze reactions?
By decreasing the magnitude of the activation energy barrier.
What is the transition state?
A state where compounds resembling it are usually effective inhibitors of that reaction.
What is the enzyme-substrate complex?
The bond between enzyme and substrate is most of the time noncovalent.
What affects the rate of reactions?
Changes in pH can affect the rate of reactions.
What is the role of amino acids in enzymes?
They can give or accept protons to or from the substrate, changing the substrate’s electrostatic character.
What is the Michaelis-Menten model?
It describes enzyme kinetics including maximal velocity, turnover number, and Michaelis constant.
What are the types of enzyme inhibitors?
Reversible and irreversible.
What are the two types of reversible inhibitors?
Competitive and noncompetitive.
What does the first law of thermodynamics state?
It is the law of conservation of energy.
What is energy transduction?
Cells are capable of energy transduction, storage, and transport, with photosynthesis being the most important.
What does the second law of thermodynamics state?
Events in the universe have direction, tending to proceed downhill from higher energy to lower energy state.
What is entropy?
A measure of disorder in the universe.
What is free energy?
The change in free energy (Delta G) indicates the direction and extent to which a process will happen.
What is the relationship between equilibrium constant and standard free-energy change?
The equilibrium constant allows prediction of the direction in which a reaction is favored under a given set of conditions.
What is the significance of ATP hydrolysis?
ATP hydrolysis is used to drive most endergonic processes in the cell.
What is gluconeogenesis?
The synthesis of glucose.
What is the role of feedback inhibition?
It regulates enzyme activity.
