Week 5 Flashcards
What is catabolism?
The breakdown of molecules
What is catabolism + anabolism?
Metabolism
What is the first law of thermodynamics?
Energy cannot be created or destroyed
What is letter of the alphabet represents enthalpy?
H
What is enthalpy change or delta H?
This is the amount of heat released or absorbed when a chemical reaction occurs at constant pressure
What is the second law of thermodynamics?
That the universe tends towards disorder
What is the term used to measure disorder?
Entropy (S)
Thinking about Gibbs free enrgy…during catabolism is energy being released or does it require energy? What about anabolism?
Catabolism = energy release
Anabolism = requiring energy
What is the equation to calculate gibbs free energy? (Delta G)
Change in free energy = change in heat - change in temperature x change in entropy
In a exergonic reaction will the gibbs free energy be positive or negative? What about the change in heat?
gibbs free energy = negative value
change in heat = negative value
In a endergonic reaction will the gibbs free energy be positive or negative? What about the change in heat?
gibbs free energy = positive value
change in heat = positive value
In cells where is chemical energy stored?
In the chemical bonds of organic molecules
In relation to the electrons, what is oxidation?
The removal of electrons from an atom
In relation to the electrons, what is reduction?
The addition of electrons to an atom
What is the type of reaction where oxidation and reduction occur at the same time?
This is a REDOX reaction
During oxidation do the number of C-H bonds increase or decrease? What about during a reduction reaction?
Oxidation = C-H bonds decrease
Reduction = C-H bonds increase
What are the three energy carriers?
- NADH
- NADPH
- FADH
How many electrons will NAD and NADPH carry?
2 electrons
What does FAD carry?
- 2 electrons
- 2 hydrogens
Which phosphate group carries the most amount of energy in ATP?
The breaking of the first phosphate group
What reaction occurs when breaking a phosphate group of ATP?
It is hydolysis
ATP + H2O –> ADP + Pi + free energy
What cofactor/ion does ATP need to work?
Mg2
What do enzymes do?
- catalyse reactions
- provide speed, specificty and control of reactions
What are the three reactions that are catalysed by enzymes?
- binding of a substrate
- conversion of bound substrate to bound product
- release of product
What do enzymes do to the activation energy?
They lower the activation energy
What are cofactors?
They are coenzymes to further facilitate substrate change
What are coenzymes made of?
- Metal ions
- organic molecules
- Vitamins
Does the substrate concentration affect the reaction rate?
Yes it does.
What is saturation?
This is where all enzyme is bound to the substrate
What is Vmax?
This is saturation
What is Km?
- It is the affinity constant
- it is 1/2 Vmax
If they have a low substrate concentration will they have a high or low affinity?
-they will have a high affinity
If there is a high substrate concentration will the enzyme have a low or high affinity?
It will have a low affinity
What is the equation to work out the slope of a Lineweaver-Burk Transformation?
Slope = Km/Vmax
What is a competitive inhibition?
It is an enzyme that binds to the active site and prevents the substrate from binding
What is an uncompetitive inhibitor?
It binds to the enzyme-substrate complex, preventing the release of products
What is non-competitive inhibitor?
Binds to a site other than the active site, changing enzyme structure so that normal substrate binding cannot occur
What are the two mechanisms that change the conformation of the enzyme?
- allosteric activation and inhibition
- conformational changes
What is the difference between allosteric and non-allosteric enzymes?
- allosteric will have multiple active sites and non-allosteric will only have one
- Allosteric enzymes are sensitve to low concentrations of inhibitors and will regulate metabolic pathways
What is feedback inhibition?
This is where the final product will acts as a noncompetitive inhibitor of the first enzyme, which shuts down the pathway
