integration of metabolism Flashcards
what organ can carry out all metabolic pathways
liver
what molecules act as metabolic junction points?
glucose-6-phosphate
pyruvate
acetyl-CoA
end products assoociated with glucose-6-phosphate
glycogen (via glycoogen metabolism)
pyruvate (via glycolysis and gluconeogenesis)
ribose-5-phosphate (via PPP)
end products associated with pyruvate
acetyl-CoA (via pyruvate dehydrogenase)
lactate (via lactate dehydrogease in exercising muscle)
alanine (via transamination)
OAA (via TCA cycle)
end products associated with acetyl-CoA
CO2 (via TCA cycle)
ketone bodies (via ketone body metabolism)
fatty acids (via fatty acid metabolism)
preferred energy source of red blood cells
glucose
preferred energy source of brain
glucose
ketone bodies
prferred energy source of adipose tissues
glucose
fatty acids
preferred energy source of liver
fatty acids
preferred energy source of muscles
glucose
fatty acids
amino acids
liver: MVP of metabolism:
- processes most ____ ____
- responds quickly to ____ ____
- maintains constant concentrations of nutrients in blood regardless of ____ ____
- synthesizes and secretes ____
- processes ____ and ____
- primarily depends on ____ of ____ ____ for its own energy needs
- ____ ____ go directly to the liver through the portal vein after absorption
- uses amino acids to make ____ , for biosynthesis of ____-containing molecules, for ____ , or for ____
- incoming nutrients
- dietary conditions
- food intake
- proteins
- toxins and wastes
- beta-oxidation of fatty acids
- amino acids
- proteins, nitrogen, gluconeogenesis, fuel
adipose: the main assist:
- synthesizes and stores ____ as signaled by ____ (fed state)
- releases ____ ____ and ____ as signaled by ____/____ (hunger, exercise)
- triacylglycerols, insulin
- fatty acids and glycerol, glucagon/epinephrine
brain: an energy consumer:
- has no significant energy ____
- high dependence on blood ____
- uses ____ % of total O2 consumed by resting humans
- after days of low glucose consumption, switches to metabolism of ____ ____ for energy needs
- metabolized by ____ ____
- prevents ____ breakdown for energy purposes
- reserves
- glucose
- 20
- ketone bodies
- TCA cycle
- protein
heart:
- cardiac muscle is exclusively ____
- ____ , ____ , ____ ____ , and ____ ____ serve as fuel
- no ____ stores
- lack of O2 leads to tissue death ( ____ ____ )
- aerobic
- glucose, lactate, fatty acids, and ketone bodies
- glycogen
- myocardial infarction
skeletal muscle: the consumer:
- rich in ____
- glycogen readily broken down to ____ which is used by the muscle for glycolysis
- lack ____ , so muscle cannot export glucose
- uses ____ ____ and ____ ____ for energy
- glycogen
- glucose-6-phosphate
- glucose-6-phosphatase
- fatty acids and ketone bodies
energy systems
ATP/PCr system =
anaerobic glycolysis =
oxidative system =
immediate
short-term
long-term
types of fueld sources: speed
- slowest:
- intermediate:
- fastest:
- generation of ATP by oxidative phosphorylation, fatty acid metabolism
- generation of ATP by glycolysis and glycogenolysis
- phosphagen: regeneration of ATP by phosphocreatin (via phosphocreatine kinase)
types of fuel sources: total energy production:
- least
- intermediate
- most
- phosphagen: regeneration of ATP by phosphocreatine
- generation of ATP by glycolysis and glycogenolysis
- generation of ATP by oxidative phosphorylation, fatty acid metabolism
phosphagen system:
- ____ bursts of activity (e.g. sprinting)
- quick ____ of ____ stores (within 1-2 seconds)
- replenished by metabolism of ____ (within 5-6 seconds)
- stored in muscle to quickly regenerate ____ from ____ )
- phosphocreatine + ____ → ____ + ____ (via ____ ____ )
- quick
- exhaustion of ATP
- phosphocreatine
- ATP from ADP
- ADP → ATP + creatine (via phosphocreatine kinase)
anaerobic glycolysis:
- further intense activity (past the ATP-PC phase) about ____ seconds
- ____ of free blood glucose or glycogen ( ____ )
- next, formation of ____
- glycogen → ____ → ____ → ____
- causes decrease in ____ and ____ fatigue
- must shift to a longer, more sustainable ____ production system
- 30
- oxidation (glycogenolysis)
- lactate
- G-6-P → pyruvate → lactate
- power and muscle fatigue
- energy
fact of lactate:
- corci cycle: cooperation between ____ and ____
- regenerate ____ from ____
- muscle and liver
- glucose from lactate
oxidative phosphorylation:
- metabolic processes involving the ____ ____ ____ in mitochondria, results in the reduction of co-enzymes (i.g. forms NADH)
- OXPHOS: production of energy from the oxidation of coenzymes NADH , FADH2 ( ____ and ____ ATP respectively)
- pumping protons out of the mitochondrial matrix builds a proton concentration in the ____ ____
- produces ____ via ____ ____
- electron transport chain
- 3 and 2
- intermembrane space
- ATP via ATP synthase
ATP:ADP and NADH:NAD+ ratios:
- energy charge of a cell is defined as the ratio of ____ to ____
- the reducing power of a cell is defined as the ratio of ____ to ____
- the reducing power represents the ____ energy and varies inversely to th ATP:ADP ratio
- when ATP levels are low, TCA cycle is upregulated to produce more ____ as a substrate for OXPHOS
- when ATP levels are high, TCA is downregulated to limit the amount of ____ created and oxidized by the ETC
- ATP to ADP
- NADH to NAD+
- potential
- NADH
- NADH
satiation signals:
- ____ is secreted by small intestine in response to a meal
- results in ____ satiety
- ____ food intake
- ____ body weight
- ____ is secreted by L cells in the intestine
- results in ____ satiey
- ____ insulin secretion
- ____ insulin biosynthesis
- cholecystokinin (CCK)
- increased
- decreased
- decreased
- glucagon like peptide-1
- increased
- increased
- increased
signals from GI tract - induce satiety:
- short-term signals: relay feelings of ____ from gut to various regions of the brain (reduce urge to eat)
- ____ : a family of peptide hormones secreted into the blood by cell in the duodenuym and jejunum regions of the small intestines as a ____ signal
- CCK binds to its receptor, a ____ located in various peripheral neurons, that rely signals to the brain
- binding initiates a signal-transduction pathway in the brain that generates a feeling of ____
- CCK also helps in digestion, stimulating secretion of ____ enzymes and ____ ____ from the gallbaldder
- satiety
- cholecystokinin (CCK) postprandial
- G-protein coupled receptor
- satiety
- pancreatic , bile salts
____ a peptide secreted by stomach, acts on regions of the hypothalamus to stimulate appetite through its receptor
secretion increases:
ghrelin
befoore a meal and decreases afterward
leptin:
- secreted by ____ tissue in direct propotion to ____ mass
- acts through leptin receptor expressed in ____
- regulates body weight
- ____ food intake
- ____ energy expenditure
- mice lacking leptin are ____ but lose weight if given leptin
- adipose fat
- hypothalamus
- inhibits
- stimulates
- inhibits
- obese
long-term control over caloric homeostasis: role of leptine and insulin:
- leptin:
- insulin:
- secreted by adipocytes (reportts on the status of triacylglycerol stores)
- secreted by beta cells of pancreas (reports on the status of blood glucose, i.e. carbohydrate availability)
the fed state - liver:
- glycolysis
- glycogen synthesis
- TAG synthesis
the fasting state - liver:
- glycogenolysis
- gluconeogenesis
- fatty acid oxidation
- ketone body formation (from excess acetyl CoA)
starvation - prolonged fasting state:
- acetyl-CoA produced to ____ ____ for use by brain
- red blood cells: lactate undergoes ____ cycle to reproduce glucose for RBCs and brain
- ketone bodies
- cori
insulin deficiency or resistance can lead to
hyperglycemia, metabolic syndrome, and diabetes
effects of insulin:
- ____ glucose uptake (muscle adipose) via ____ glucose transporter
- ____ glucose trapping (liver) via ____ glucokinase
- ____ glycogen synthesis (liver, muscle) via ____ glycogen synthase
- ____ glycogen breakdown (liver, muscle) via ____ glycogen phosphorylase
- ____ glycolysis, acetyal Co-A productiton (liver, muscle) via ____ PFK-1 (by increased PFK-2
- ____ FA synthesis (liver) via ____ acetyl-CoA carboxylase
- ____ triacylglycerol synthesis (adipose tissue)
- ____ gluconeogenesis
- increased, increased
- increased, increased
- increased, increased
- decreased, decreased
- increased, increased
- increased, increased
- increased, increased
- decreased
effects of glucagon:
- ____ glycogen breakdown (liver) via ____ glycogen phosphorylase
- ____ glycogen synthesis (liver) via ____ glycogen synthase
- ____ glycolysis (liver) via ____ PFK-1
- ____ gluconeogenesis (liver) via ____ FBPase-2
- ____ FA mobilization (adipose tissue) via ____ triacylglycerol lipase
- ____ ketogenesis
- increased, increased
- decreased, decreased
- decreased, decreased
- increased, increased
- increased, increased
- increased
epinephrine:
- ____ heart rate
- ____ blood pressure
- ____ dilation of respiratory passages
(increase delivery of O2 to tissue (muscle)
- increase
- increase
- increase
epinephrine:
- ____ glycogen breakdown (muscle, liver)
- ____ glycogen synthesis (muscle, liver)
- ____ glucogneogensis
(increase production of glucose for fuel)
- ____ glycolysis (muscle)
(increases ATP production in muscle)
- ___ FA mobilization (adipose tissue)
(increases availability of FAs as fuel)
- ____ glucagon secretion
- ____ insulin secretion
(reinforce metabolic effects of epinephrine)
- increase
- decrease
- increase
- increase
- increase
- increase
- decrease
overall energy sensory in cells:
- ____ ____ ____ (AMPK) is the cellular energy sensor
- when ATP is ____ , AMPK is inactive
- when ATP is ____ , AMPK is allosterically activated and ____ many targets controlling cellular energy production and consumptions
- the competition between ____ and ____ for binding to the AMPK allosteric sites determines the activity of AMPK
- AMP-activated protein kinase
- high
- low, phosphorylates
- ATP and AMP
regulation of energy homeostasis by AMPK:
- ____ FA uptake and oxidation, glucose uptate, glycolysis in heart
- ____ hypothalamus, food intake
- ____ FA uptake and oxidation, glucose uptake, mitochondrial biogenesis in muscle
- ____ FA synthesis, lipolysos in adipose tissue
- ____ FA synthesis, cholestoerl synthesis, glucogenogenesis in liver
- ____ insulin secretion in pancreatic b-cells
- increase
- increase
- increase
- decrease
- decrease
- decrease
AMPK ____ anabolism
AMPK ____ catabolism
decrease
increase
