Bioenergetics and Regulation Flashcards
Internal energy change of a closed system
ΔU = Q - W
work constant in most living systems
change in free energy physiological conditions
ΔG = ΔG° + RTln(Q)
least stable to most table energetic compound
cAMP
creatine phosphate
ATP
ADP
G6P
AMP
pmf of ETC
electrons passed down ETC, give up free energy for form the pmf across inner mitochondrial membrane
flavoproteins
- contain modified B2 riboflavin
- presence in mitochondria and chloroplasts as e- carriers
- coenzymes for FA oxidation, decarboxylation of pyruvate, and reduction of glutathione
- modification of other B vit
insulin effects
- glycogen synthesis in liver and muscle (promote glucokinase and inhibit G6Pase)
- liver convert XS gluc to FA and triacylglycerols
- triacylglycerol synthesis in adipose tissue
- gluc and triacylglycerol uptake by fat cells
- lipoprotein lipase activity clearing VLDL abs chylomicrons from blood
- protein synthesis in muscle
dec lipolysis in adipose tissue and ketone formation by liver
after a meal how are energy needs of liver met?
oxidation of XS aa
in well-fed and normal fasting states, how does nervous tissue sustain itself
oxidizing gluc to CO2 and water
how do RBCs sustain themselves
- use gluc anaerobically
hormones that oppose insulin actions
glucagon, cortisol, epi, NE, and GH
effects of glucagon and epi
- glycogen degradation in liver
- gluc release into blood
- hepatic gluconeogenesis
- epi causes aa and FA release from skeletal and adipose for gluconeogenesis
once elevated FA and ketone levels are reached…
muscle used FA as major fuel source and brain uses ketones to spare aa for proteins
tissues in which glucose uptake not affected by insulin…
nervous
kidney tubules
intestinal mucosa
RBCs
β-cells of the pancreas
tissues in which insulin is effective for gluc uptake
resting skeletal tissue and adipose tissue
glucagon activates __________ and inactivates ___________
glycogen phosphorylase
glycogen synthase
in terms of ketones and fats, glucagon…
inc liver ketogenesis and dec lipogenesis
in lipolysis by activating lipase
glucagon converts pyruvate to _________ by _________ in liver to promote __________. It also ____.
PEP
PEPCK
gluconeogenesis
inc conversion of F1,6-BP to F6P by F-1,6-BPase
cortisol
glucocorticoid
adrenal cortex
sympathetic response
steroid hormone
promotes mobilization of energy stores
inc aa delivery, lipolysis, and blood glucose levels
XS will promote insulin release
catecholamines
secreted by adrenal medulla
epi, NE
inc activity of liver and muscle glycogen phosphorylase promoting glycogenolysis
inc lipolysis
adrenaline rush
inc BMR through sympathetic NS
Thyroid hormone functions
inc BMR
accelerate cholesterol clearance from plasma and inc gluc absorption in small intestine
Epi dependent on thyroid hormones
T3 faster than T4
BMI
BMI = mass/(height^2)
above 30 obese
25-30 overweight
18.5-25 normal
ghrelin
secreted by stomach in response to impending meal
inc appetite and signals for orexin release
orexin
inc appetite
alertness
triggered by hypoglycemia
leptin
secreted by fat cells
dec appetite
suppress orexin production
mutation implicated in obesity
respirometry/respiratory quotient
RQ = CO2 consumed/O2 consumed
1.0 for carbs
0.7 for lipids
0.8 in humans at rest
calorimeter measure…
BMR
liver role
- maintain blood gluc
- syn ketones when XS FA oxidized
- replenish glycogen stores
- XS gluc used to make acetyl CoA for FA synthesis
- process and release FA as VLDL
- most energy comes from aa oxidation
- glycogen degradation and gluconeogenesis
- provide carbon skeletons for glucose synthesis
adipose tissue role
- elevated insulin levels gluc uptake
- release FA from VLDL and chylomicrons
- lipoprotein lipase induced by insulin
- for triacylglycerols for storage
- insulin suppresses FA release
- dec insulin and inc epi activate hormone sensitive lipase for FA to be released into circulation
resting muscle energy consumption
- major fuels gluc and FA
- in fasting state, FA derived from bloodstream
- ketone bodies used for energy if fasting is prolonged
active muscle energy consumption
- short lived, creatine phosphate which transfers a P to ADP to form ATP
- short high intensity exercise, anaerobic glycolysis and draw on stored glycogen
- moderate high intensity continuous oxidation of gluc and FA
- lengthy high intensity exercise, glycogen depleted and FA oxidation takes over
cardiac muscle energy consumption
- prefer FA
- ketones during prolonged fasting
- in a failing heart, gluc oxidation inc and B-ox falls
brain energy consumption
- glucose primary fuel
- ketones during prolonged fasting
- between meals, glycogenolysis and gluconeogenesis
- hypothalamic center signal for epi and glucagon release in hypoglycemic conditions
