Metabolism Flashcards
Catabolic pathways
Oxidize complex molecules, generating smaller molecule. Release energy in process
Anabolic pathways
Synthesize complex molecules from smaller molecules and require energy input
What are the two metabolic pathways?
Catabolic and Anabolic
What are the major macronutrients?
Fat
Carbohydrate
Protein
What is the fed state?
Your diet
What is included in the fasting state?
Carbohydrate released from glycogen deposits and synthesized from amino acids
Fat released from triacylglyceride stores
Protein from catabolism of muscle protein, releasing free amino acids
What is the acceptable macronutrient distribution range for carbs?
45%-65%
How many calories in 1 g of carbohydrates?
4 kcal
What are digestible carbs and what do they degrade to?
Mostly starch and degraded to glucose, which is needed by red blood cells, brain, and many tissues
What is the acceptable macronutrient distribution range for fat?
20%-35%
How many calories in 1g of fat?
9 kcal - energy dense
What is the major fat source, what does it degrade to, and what is it important for?
Triacylglycerols
Degraded to fatty acids that are important energy source for skeletal and cardiac muscle, used by liver, but NOT the brain
What is the acceptable macronutrient distribution range of protein?
10%-35%
How many calories in 1g of protein?
4 kcal
What is protein degraded to and where is it abosorbed?
Amino acids.
Absorbed by various tissues for protein synthehsis and oxidation of energy
Partial oxidation occurs in the liver when used for gluconeogenesis or lipogenesis
What is the “other” source of calories?
Alcohol. Produces 7 kcal per 1g of ethanol.
What is the driving net force of a reaction?
Gibbs free energy change
What does it mean when Gibbs free energy change is negative?
Spontaneous reaction. Products have less free energy than reactants
What does Gibbs Free Energy equal at equilibrium?
0
Does Gibbs Free Energy tells us about rate of a reaction?
no!!!
What are standard conditions for free energy change? What does it allow?
concentration of reactant and product = 1M
Pressure of 1 atm
Temperature of 25 degrees Celsius
pH of 7
Change in Gibbs Free Energy is constant
*Allows reactions to be compared under identical conditions
What does Gibbs free energy change rely on?
Depends on relative concentration of products and reactants
How does metabolism relate to Gibbs Free Energy change?
Products often removed during metabolism which changes the concentration of products and then changes gibbs free energy change
Reaction coupling. What is the overall free energy change?
Two reactions can be coupled together if they share common intermediates. Overall free energy change for a couples series is equal to the sum of the free energy changes of the individual steps.
What does it mean if change in gibbs free energy is positive?
Reaction is unfavored, would want to go backwards under standard conditions
Oxidative Phosphorylation
Occurs in mitochondria and associated with inner mitochondrial membrane
Reduced electron carriers (NAHD, FADH2) are re-oxidized to NAD+ and FAD+ and electrons are transferred to O2 so O2 is reduced to H2O
Results in release of free energy and used to phosphorylate ADP to ATP
Oxidation
Loss of electrons
Reduction
Gain of electrons
Oxidation of metabolites results in reduction of what electron carriers?
NAD+/NADP+
FAD
FMN
Reduction Potential
How willing a compound is to accept electrons. Measured in Volts and given he symbol E prime’
Compounds that accept electrons and become reduced have ____
Positive E prime’ and are oxidizing agents
Compounds that donate electrons and become oxidized have _____
Negative E prime’ and are reducing agents
Why is the free enrgy from the transfer of electrons from NADH to oxygen important?
Harnessed to synthesize ATP by the mitochondria
What do NAD+/NADP+ contain?
Nicotinamide which is derived from niacin (vitamin B3)
What is FAD/FMN contain?
Riboflavin, vitamin B2
What happens with deficiency of niacin?
Common in alcohol use disorders
Symptoms include pellagra - dermatitis, diarrhea, dementia
