MCC111 CHAPTER 15:METABOLISM Flashcards
Organisms that obtain energy from sunlight.
Phototrophs
Organisms that obtain energy from oxidation of carbon fuels.
Chemotrophs
Refers to all the defined pathways in the cell.
Intermediary metabolism
Metabolic pathway that transforms fuel molecules into energy.
Catabolic pathways
Metabolic pathway that uses energy to synthesize new molecules.
Anabolic pathways
What defines a favorable/unfavorable reaction?
favorable-negative free energy values
unfavorable-positive free energy values
Metabolic pathways frequently contain reactions with positive free-energy values, yet the reactions still take place. How is this possible?
A reaction with a positive free-energy value can be coupled with a reaction with a negative free-energy value to get a negative net free energy value.
The universal currency of free energy that contains two phosphoanhydride bonds–high energy bonds.
ATP
What products result from the hydrolysis of ATP?
Adenosine Diphosphate or adenosine monophosphate
(ADP or AMP)
In cell conditions, what is the energy of hydrolysis?
~50 kJ/mol
Under standard conditions, ATP hydrolysis can change the equilibrium by a factor of __.
-electrostatic repulsion
-resonance stabilization
-stabilization by hydration
Name three compounds that are higher in energy than ATP.
-phosphoenolpyruvate (PEP)
-1,3-bisphosphoglycerate
-creatine phosphate (CP)
What makes ATP a good constituent/carrier for many reactions?
ATP has high free energy that can shift equilibrium of a reaction, but not so high that it can’t be resynthesized when it’s needed.
What provides the energy for generation of ATP?
Oxidation of glucose and fats to CO2.
True or False: Oxidation of carbon compounds occurs at one step on all carbon atoms.
False - oxidation occurs one carbon at a time.
What is carbon oxidation energy used to generate?
high-phosphoryl-transfer potential or an ion gradient
Which generates more energy, carbohydrates or fatty acids, and why?
fatty acids because they are in a more reduced form than carbohydrates are.
True or False: Oxidation occurs directly.
False
Why doesn’t oxidation occur directly?
Rather than taking one highly exergonic reaction, the cell undergoes several reactions as a way to capture the electrons and energy as efficiently as possible.
What are activated carriers for catabolism?
NADH and FADH2
What are activated carriers for anabolism?
NADPH
What is an activated carrier of two carbon unites?
Coenzyme A (CoA)
How many electrons and hydrogen atoms can FAD accept?
2 e-
2 H+
How many electrons and hydrogen atoms can NAD+ accept?
2 e-
1 H+