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37 Cards in this Set
- Front
- Back
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3 catabolic pathways and their substrates:
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-Glycolysis (glu/fructose)
-TCA (AcCoA) -FA oxidation (FFA - mostly long chain) |
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What drives catabolic pathways?
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Made thermodynamically favorable by concomitant reduction/oxidation.
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In catabolic pathways what is:
-Reduced -Oxidized |
Reduced --> NAD+
Oxidized --> Carbon molecule |
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What drives anabolic pathways?
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ATP and NADPH
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In general what molecules can enter the TCA cycle? (5)
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-Glucose (pyruvate metabolism)
-Fructose (pyruvate mblsm) -Acetyl CoA (from lipids) -Succinyl CoA (minor) -Proteins (as amino acids) |
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How many reactions in the TCA cycle form CO2?
-Starting w/ glucose -Starting w/ AcCoA |
From glucose -> 3
From AcCoA -> 2 |
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What is the ultimate worth of NADH and FADH2?
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NADH = 2.5 ATP
FADH2 = 1.5 ATP |
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What is substrate level phosphorylation?
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When an ATP or GTP is produced by a reaction directly, not from NADH/FADH2.
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How does ATP provide cells with energy?
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By the nature of its 2 phospate anhydride bonds.
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What are the 2 phosphate anhydride bonds of ATP?
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1. a-B -> gives 10.9 kcal/mol
2. B-y -> gives 7.3 kcal/mol |
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Which phosphate bond in ATP provides more energy? Why?
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a-B -> because it releases more energy and also PPi which can be subsequently cleaved to produce energy.
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What enzyme hydrolyzes PPi?
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Pyrophosphatase
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What is the typical cell conc
-of ATP -of ADP |
ATP = 3-4 mM
ADP = 0.13 mM |
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What is the calc for cell energy charge?
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[ATP] + 1/2[ADP]
---------------- [ATP]+[ADP]+[AMP] |
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What is the typical energy charge of a cell?
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0.80 - 0.95
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Why do we care about cellular energy charge?
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It dictates whether catabolic or anabolic processes will predominate.
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What energy charge will call for catabolism?
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Decreased energy charge - need energy so break things down.
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What energy charge will call for anabolism?
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Increased - use energy to make things.
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What is the role of phosphocreatine in the body's energy stores?
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When [ATP] is high and exceeds immediate needs, creatine is phosphorylated.
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What is creatine?
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A tissue protein especially in skeletal muscles
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What happens to phosphocreatine when cell energy stores are low?
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The phosphate is used to convert ADP -> ATP
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What enzyme catalyzes the converstion from creatine to phosphocreatine?
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Creatine phosphokinase (aka creatine kinase)
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What is the specific benefit of phosphocreatine?
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It provides short burts of energy for activities like weight lifting.
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How many electrons are stored in NADH?
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2
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How exactly are electrons stored in NADH, and what makes them so useful?
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As 2 hydride ions - they are highly energetic.
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What role does NADPH have in the body?
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-Biosynthesis
-Antioxidant defense mechanisms |
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How many electrons are stored by FADH2?
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One (FADH') or two (FADH2)
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Why is AcCoA useful in metabolism?
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It can transfer acyl or acetyl groups; contains a high energy thioester bond that makes these transfers thermodynamically favorable.
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What is the body's metabolic response to high energy levels
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-Store glucose as glycogen
-Store trygl. as fat |
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What do allosteric regulators affect?
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The irreversible steps of commitment in metabolic pathways -> short term
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What type of modification is:
-allosteric -hormonal |
allosteric = noncovalent
hormonal = covalent |
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What 2 processes control metabolism in the long term?
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-Gene regulation/induction
-Protein turnover (enzyme degradation) |
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What is 'futile cycling'?
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Simultaneous degradation and synthesis of metabolic intermediate.
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What is used to prevent futile cycling?
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-Tight allosteric regulation
-Compartmentalization -> keeps common intermediates separate. |
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List the 9 processes in the cytoplasm:
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1. Cholesterol breakdown
2. FA biosynthesis 3. Tryglyc. synthesis 4. Glycolysis 5. Glycogenesis/olysis 6. HMP shunt (PPP) 7. Nucleotide synth/bkdown 8. Gluconeogenesis (part) 9. Urea cycle (part) |
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List the 6 processes in mitochondria:
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1. TCA cycle
2. ETC/oxidative phosphoryln 3. FA oxidation 4. Urea cycle (part) 5. Gluconeogenesis (part) 6. Amino acid oxidation |
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What very important enzyme is in the endoplasmic reticulum?
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Glucose-6-phosphatase
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