FINAL EXAM CHAPTER 15 Metabolism Flashcards
What are the three stages of catabolism?
- Large molecules in food are broken down into smaller molecules in the process of digestion
- The many small molecules are processed into key molecules of metabolism most notably acetyl CoA
- ATP is produced from the complete oxidation of acetyl CoA
Where does energy come from in Phototrophs and Chemotrophs?
Phototrophs - Obtain energy by capturing sunlight
Chemotrophs - Obtain energy through the oxidation of carbon fuels
What is energy used for?
-To do work : power muscle contraction, cell movement
-Active transport
-Biosynthesis of macromolecules
Define Metabolism
A series of linked reactions that convert a specific reactant into a specific product
Define catabolism
the break down of complex molecules
Define anabolism
the simple molecules combine to generate complex molecules
What are catabolic pathways?
Combustion of carbon fuels to synthesize ATP or ion gradients
What are anabolic pathways?
Uses ATP and reducing power to synthesize large biomolecules
How can we perform thermodynamically unfavorable reactions?
by coupling these reactions to a more favorable one
What is the importance of ATP as a common intermediate in all of metabolism ?
It is the energy currency if the cell and it is used for building cell constituents and doing cellular work such as muscle contraction and active transport of molecules against concentration gradients
Why are Delta G sequential reactions additive?
Because delta G is path independent
Why does ATP have a high phosphoryl transfer potential?
- Charge repulsion
- Resonance stabilization
- Increase in entropy
- Law of Mass action
- Stabilization by hydration.
What are the two molecules that we discussed have high phosphoryl transfer potential
-Phosphoenolpyruvate(PEP)
-1,3-Biphosphoglycerate
Explain the concept of being thermodynamically unstable but kinetically stable
in things like Phosphate esters you would see this, as the inherent negative charge resist hydrolysis and this happens in things where the condition in where the reaction should happen isn’t met
Why is the oxidation of carbon fuel important?
Because it helps regenerate ATP and ATP is limited so it has to be recycled.
Explain how carbon oxidation is paired with a reduction?
The carbon atoms in fuels are oxidized to yield CO2 and the electrons are accepted by oxygen to form H2O
-The more reduced a carbon atom is the more free energy is released upon oxidation
why are fats more efficient food source than glucose ?
Because fats are more reduced
What are the two common characteristics of activated carriers?
- The carriers are kinetically stable in the absence of specific catalysts
2.The metabolism of activated groups is accomplished with a small number of carriers
What is the activated carrier of phosphate?
ATP
What are the activated carriers of electrons?
-NAD+
-FAD
both carry activated electrons derived from the oxidation of fuels
What is the activated carrier of Acetyl groups?
-Coenzyme A (CoA or CoA-SH)
what carriers are often derived from vitamins?
Coenzymes are usually derived from vitamin B
