Lecture 7- Metabolism Flashcards
What is anabolism?
Synthesis of complex molecules from simpler ones
What is the difference between kinetic energy and potential energy?
Potential energy is the stored energy in an object or system due to its position or configuration, whereas kinetic energy is the energy which a body possesses by virtue of being in motion
True or false: Gibbs free energy can be directly measured
False; Gibbs free energy cannot be measured directly
How can energy be defined?
The capacity to do work
What is adenosine triphosphate (ATP) composed of?
Ribose (pentose sugar), adenine (nitrogenous base), & three phosphate groups
What is entropy?
Quantitative measurement of the degree of disorder within a system
What do we know about a system if the change in Gibbs free energy is positive?
Reaction is endergonic and nonspontaneous
What is a redox reaction?
Reaction in which a substance is reduced and another substance is oxidized (transfer of electrons)
What is catabolism?
The breakdown of complex molecules into simpler ones
What does the hydrolysis of ATP result in?
Adenosine diphosphate (ADP) & inorganic phosphate
What are the first and second laws of thermodynamics?
Energy cannot be created nor destroyed & every transfer of energy increases entropy in the universe
What do we know about a system if the change in Gibbs free energy is negative?
Reaction is exergonic and spontaneous
What is an enzyme?
Biological catalyst
What is Gibbs free energy?
Energy available to do work
What do we know about a system if the change in Gibbs free energy is equal to zero?
Chemical processes at equilibrium (rate of forward reaction is equal to rate of reverse reaction)
True or false: In competitive inhibition, an inhibitor binds to the allosteric site of an enzyme, preventing the substrate from binding to the active site
False; this is an example of non-competitive inhibition
Where in ATP is energy stored?
In the ‘spring-loaded’ phosphoanhydride bonds between phosphates
What is a substrate?
Reactant molecule that an enzyme acts upon
What process adds phosphate to ADP to form ATP?
Phosphorylation
What region(s) of an enzyme can a substrate bind to?
Active site
What is a catalyst?
Substance that increases the rate of a chemical reaction by lowering the activation energy, without itself undergoing any permanent chemical change
What is NAD+ ?
Coenzyme electron carrier
True or false: Enzymes generally function optimally at a certain temperature and pH, which varies amongst different enzymes
TRUE
What occurs during competitive inhibition?
Inhibitor binds to enzymatic active site, physically preventing substrate from binding to enzyme
What does it mean for a substance to undergo reduction?
Reduction is the gaining of electrons (OIL RIG)
What is the difference between cofactors and coenzymes?
Cofactors are generally inorganic (often metals) whereas coeznymes are organic
What does it mean for a substance to undergo oxidation?
Oxidation is the loss of electrons (OIL RIG)
How does increasing temperature effect enzymatic activity?
Slight increase in temperature can accelerate enzymatic activity but a significant increase in temperature will denature the enzyme and render it useless
