Metabolism Flashcards
___________________ represents the totality of reactions a given cell or organism carries out.
Metabolism
What are the four general roles of metabolism?
- Energy generation
- Nutrient breakdown
- Biomolecule synthesis
- Specialized molecule synthesis (i.e., hormones)
_____________ ____________ are a series of connected reactions that produce specific products.
Metabolic pathways
________________ are defined as intermediates or products of metabolism.
Metabolites
Metabolic pathways are _________, cyclic, or branched.
Linear
What three types of metabolic pathways are there?
- Linear
- Cyclic
- Branched
What is an example of a linear metabolic pathway?
Glycolysis
What is an example of a cyclic metabolic pathway?
The Krebs Cycle (the Citric Acid Cycle)
What is an example of a branched metabolic pathway?
Eicosanoid synthesis
Catabolic pathways are ______________, oxidative, _________________, and energy-releasing
Degradative
Oxidative
Convergent
Energy-releasing
Anabolic pathways are ____________, reductive, divergent, and ____________ ____________.
Synthetic
Reductive
Divergent
Energy requiring
What types of pathways are degradative, oxidative, convergent, and energy releasing?
Catabolic
Why types of pathways are synthetic, reductive, divergent, and energy requiring?
Anabolic pathways
Catabolism and anabolism are connected by three factors. What are they?
- Energy products
- Carbon skeletons
- Reducing molecues
In oxidation-reducation reactions, electrons are transferred from an electron donor or ____________ agent to an electron acceptor or ___________ agent
Reducing agent
Oxidizing agent
Reducing agents become _____________; oxidizing agents become ____________
Oxidized
Reduced
How do electrons spontaneously flow?
From low to high standard reduction potentials
What is the mathematical relationship between Gibbs Free energy and the standard reduction potential?
Do you multiple the standard reduction potential by the moles of a reaction?
No, never
How do we account for non-standard conditions?
The Nernst Equation
∆G’ = ∆Go’ + RTlnQ
∆G’ = -nF∆Eo’ + RTlnQ
How are standard reduction potentials related to electron affinities (i.e., the greater the tendency of a species to accept electrons and therefore be reduced)?
The higher the standard reduction potential, the higher the electron affinity and the more likely the species is to accept electrons and be reduced
The lower the standard reduction potential, the lower the electron affinity and the more likely the species is to give up electrons and be oxidized
_______________ _____________ like NAD+ and FAD are required for cellular redox reactions
Electron carriers
Which electron carrier - NAD+ or FAD - is reversibly bound to an enzyme and thus considered a cosubstrate?
NAD+
Which electron carrier - NAD+ or FAD - tightly associates with enzymes and is often considered a prosthetic group?
FAD
There are four general types of metabolic reactions. What are they?
- Redox
- Make/break C-C single bonds
- Group transfer (phosphoryl, acyl, glycosyl)
- EIR - eliminations (dehydrases), isomerizations (isomerases), and rearrangments (mutases)
What carbons are most reduced and oxidized?
Why is 3-phosphoglycerate not a high-energy compound?
Because upon its hydrolysis, only a phosphoester bond is formed, not the high energy phosphoanhydride boned; there is no additional resonance or ionization; and no lowering of charge repulsion
Which path will G6P take if more ribose is needed than NADPH?
Non-oxidative PPP (in “reverse”)
Glycolysis (produces F6P and GAP, which are “reactants” in non-oxidative PPP)
Which path will G6P take if NADPH and ribose needs are balanced?
Oxidative PPP
What path will G6P take if more NADPH is needed than ribose?
Oxidative PPP (to produce NADPH)
Non-oxidative PPP (recycle ribose to GAP and F6P)
Gluconeogenesis (GAP and F6P to G6P)
Which path will G6P take if both NADPH and ATP are required?
Oxidative PPP (NADPH)
Non-oxidative PPP (ribose to F6P and GAP)
Glycolysis (G6P and GAP yield ATP)
What is the structure of glycerol?
If the liver is synthesizing fats and making nucleotides, what paths of the pentose phosphate pathway are operating?
Oxidative PPP (ribose)
Non-oxidative PPP (F6P & GAP)
Gluconeogensis (G6P)
If the liver requires ribose for nucleotide synthesis, which pathways are operating?
Glycolysis (F6P & GAP)
Non-oxidative PPP (in reverse for ribose)
