IAS16 Flashcards
metabolism significance
Secure useful substances (for synthesis of biomolecules OR energy generation in form of ATP)
Get rid of harmful substances
Keep substances in safe level in blood
catabolism relation w/ anabolism
catabolism breaks down large substances into small substances; anabolism creates large substances from small substances
catabolism converges, anabolism diverges
catabolism supplies energy for anabolism
FA, glucose, AA metabolism convergent point
acetyl coA -> TCAC -> electron funneling in ETC to generate ATP
TCAC intermediates anabolism
siphoned out for biosynthesis:
OAA -> carbs through PEP carboxykinase & GNG
citrate -> lipids
OAA, malate & ketoglutarate -> AA / proteins
TCAC intermediates anabolism effect
less intermediates running TCAC, incomplete -> lower rate of ATP production
replenishment of TCAC intermediates
anaplerotic Rx
pyruvate -> (malic enzyme) malate
pyruvate -> (pyruvaate carboxylase) OAA
PEP -> (PEPK) OAA
regulation of metabolism: why
simul. formation & degradation of organic products is a waste -> cat / ana are reciprocally regulated i.e. active pathway supresses other
regulation of metabolism methods
diff. enzymes used for cat & ana to control rate of Rx with same starting & end points, often enzymes at start & end controlled -> dir. of Rx also controlled
cat & ana in diff. compartments -> enzymes, intermediates & reg. factor conc. all controlled
cellular level: flux of metabolites in pathway, role & metabolism of enzymes, negative feedback, transport of intermediates across organelle membrane
organism level: flux of metabolites from organ to organ, regulation by growth factors & hormones
metabolic homeostasis
to ensure enough blood circulation of fuel for ATP generation (const. flow of fuel)
balance btn: rate of intake, rate of oxidation of fuel, rate of fuel storage in excess, rate of mobilization from storage, rate of de novo synthesis
–> control of balance in substrate availability & need
metabolic homeostasis controlled by
blood concentration of metabolite affect rate of uptake or storage
hormones signal directly phy cond. of body & nutrient supply demand
nerve impulse from CNS directly influence metabolism
glucose importance
most cells use glucose preferably or solely for ATP generation & production of precursors of other pathways
blood glucose level regulated by
insulin & glucagon, blood levels change continuously depending on BGL, regulates carb, AA & lipid metabolism based on body needs: excess stored, appropriate fuel mobilized in demand
epinephrine & cortisol
insulin function
anabolism hormone
increase fuel uptake:
- glucose uptake into glycogen storage in liver
- TAG production in adipocyte
- AA uptake & protein synthesis by muscle
inhibit mobilization of fuels from stores e.g. TAG, protein & glycogen
transport glucose to muscle & liver cells to promote oxidation of glucose (as fuel) for ATP production
glucagon function
glucagon: insulin counterregulatory hormone, maintain fuel availability in absence of dietary glucose
- promote FA mobilization from adipocytes to generate ATP
- promote gluconeogenesis from AA, glycerol & lactate
- promote liver conversion from stored glycogen to glucose
no effect on muscles storage for sudden needs
epinephrine & cortisol function
blood levels mediated by CNS, insulin counter regulatory hormones, fuel mobilization in acute stress
epinephrine: promote FA mobilization from adipocyte, promote glucose production in liver
cortisol: promote FA mobilization from adipocyte, promote AA mobilization from muscles, promote gluconeogenesis
