Flashcards in Chapter 12- Bioenergetic and Regulation of Metabolism Deck (59)
what does the brain rely on for metabolism
what type of system is a biological system?
open system, b/c they can exchange both energy and matter with the environment.
energy exchanged in form of mechanical work or heat.
matter exchanged through food consumption and elimination, as well as respiration.
typically done on cellular or subcelluar level, which is considered a closed system b/c there is no exchange of energy with the environment.
- in a closed system change in internal energy can only come from work or heat (change U = Q - W).... so in this system only heat applies.
sum of all different interactions b/w and w/i atoms in a system
ex: vibration, rotation, linear motion, and stored chemicals
describes energy states in biological systems.
ex: changes in free energy.
Gibbs free energy equation
chgG = chgH -T chgS
-G = spontaneous
+G = nonspontaneous
modified standard state (G*')
necessary change in pH for biochemical reactions.
pH - 7 (usually concentration of 1, so pH of 0)
T - 25*C
p - 1 atm
most energy-rich nutrient
fats (9 kcal/g of energy), preferred for long-term energy storage.
carbs, proteins, and ketones only have about 4 kcal/g
*same physical space but more energy in it.
2 processes in which ATP is formed
1. substrate-level phosphorylation
2. oxidative phosphorylation
why is it good that ATP is a midlevel
b/c when an ATP is used it provides G*' = 30 kJ/mol of energy no matter what the reaction needs. so it may lose energy if the reaction only requires 10 kJ/mol.
if it were any larger it would waste too much.
*numbers are actually negative when releasing energy
highest to lowest G*' energy provided
(MOST NEGATIVE CAUSE RELEASES MOST ENERGY)
cAMP, Creatine phosphate, ATP, Glucose 6-phosphate, AMP (adenosine monophosphate)
(MOST POSITIVE CAUSE RELEASES LEAST ENERGY)
what is ATP typically used for
to fuel energetically unfavorable reactions or to activate or inactivate other molecules
ATP hydrolysis vs. ATP cleavage
hydrolysis: usually part of coupled reactions, like with Na/K pump
cleavage: transfer of phosphate group to another molecule-aka. phosphoryl group transfers-, typically (in)activates a target molecule
if chgG is negative and E (electromotive force) is positive then...
the oxidation-reduction reaction is spontaneous
high-energy electron carriers in cytoplasm
NADH, NADPH, FADH2, ubiquinone, cytochromes, and glutathione
flavin mononucleotide (FMN)
membrane-bound electron carriers embedded within the inner mitochondrial membrane. this one is bound to complex I of the electron transport chain and can also act as a soluble electron carrier
contain modified vitamin B12 (riboflavin). They are nucleic acid derivatives (FAD or FMN).
they are in the mitochondria or chloroplasts as electron carriers. also used as cofactors for enzymes in oxidation of fatty acids, decarboxylation of pyruvate, and reduction of glutathione.
key difference between chemistry and biochemistry?
chemistry- equilibrium states are desired
biochemistry- equilibrium states are NOT desired (homeostasis is desired instead)
physiological tendency toward a relatively stable state that is maintained and adjusted, often with expenditure of energy
aka. absorptive or well-fed state. occurs shortly after eating and lasts for 3 to 4 hours after eating. greater anabolism and fuel storage. nutrients flood from the gut to the liver via the heptaic portal vein.
insulin release due to high blood glucose levels.
synthesis of biomolecules
breakdown of biomolecules for energy
3 major target tissues for insulin
promotes glucose entry into all of these.
1. liver - promotes glycogen synthesis
2. muscle- promotes glycogen synthesis and protein synthesis
3. adipose tissue- promotes triacylglycerol synthesis
what happens after the glycogen stores are filled?
liver converts excess glucose to fatty acids and triacylglycerols
tissues that are insensitive to insulin
1. nervous tissue- gets energy from oxidizing glucose to CO2 and water
2. red blood cells- can only use glucose anaerobically cause they lack mitochondria
3. intestinal mucosa
4. kidney tubules
5. B-cells of the pancreas
postabsorptive state and counterregulatory hormones
aka. fasting state. release of amino acids from skeletal muscle and fatty acids from adipose tissue are both stimulated by the decrease in insulin and by an increase in levels of epinephrine.
counterregulatory hormones have opposite effect of insulin:
5. growth hormone
relating to the liver
aka. starvation. levels of glucagon and epinephrine are markedly elevated. rapid degeneration of glycogen stores in the liver. both gluconeogenesis and lypolysis are occurring rapidly.
typically water-soluble. able to rapidly adjust metabolic processes of cells via second messenger cascades. (ex: insulin)