integration of metabolism Flashcards

1
Q

what organ can carry out all metabolic pathways

A

liver

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2
Q

what molecules act as metabolic junction points?

A

glucose-6-phosphate

pyruvate

acetyl-CoA

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3
Q

end products assoociated with glucose-6-phosphate

A

glycogen (via glycoogen metabolism)

pyruvate (via glycolysis and gluconeogenesis)

ribose-5-phosphate (via PPP)

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4
Q

end products associated with pyruvate

A

acetyl-CoA (via pyruvate dehydrogenase)

lactate (via lactate dehydrogease in exercising muscle)

alanine (via transamination)

OAA (via TCA cycle)

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5
Q

end products associated with acetyl-CoA

A

CO2 (via TCA cycle)

ketone bodies (via ketone body metabolism)

fatty acids (via fatty acid metabolism)

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6
Q

preferred energy source of red blood cells

A

glucose

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7
Q

preferred energy source of brain

A

glucose

ketone bodies

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8
Q

prferred energy source of adipose tissues

A

glucose

fatty acids

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9
Q

preferred energy source of liver

A

fatty acids

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10
Q

preferred energy source of muscles

A

glucose

fatty acids

amino acids

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11
Q

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 ____
A
  • incoming nutrients
  • dietary conditions
  • food intake
  • proteins
  • toxins and wastes
  • beta-oxidation of fatty acids
  • amino acids
  • proteins, nitrogen, gluconeogenesis, fuel
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12
Q

adipose: the main assist:

  • synthesizes and stores ____ as signaled by ____ (fed state)
  • releases ____ ____ and ____ as signaled by ____/____ (hunger, exercise)
A
  • triacylglycerols, insulin
  • fatty acids and glycerol, glucagon/epinephrine
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13
Q

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
A
  • reserves
  • glucose
  • 20
  • ketone bodies
    • TCA cycle
    • protein
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14
Q

heart:

  • cardiac muscle is exclusively ____
  • ____ , ____ , ____ ____ , and ____ ____ serve as fuel
  • no ____ stores
  • lack of O2 leads to tissue death ( ____ ____ )
A
  • aerobic
  • glucose, lactate, fatty acids, and ketone bodies
  • glycogen
  • myocardial infarction
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15
Q

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
A
  • glycogen
  • glucose-6-phosphate
  • glucose-6-phosphatase
  • fatty acids and ketone bodies
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16
Q

energy systems

ATP/PCr system =

anaerobic glycolysis =

oxidative system =

A

immediate

short-term

long-term

17
Q

types of fueld sources: speed

  • slowest:
  • intermediate:
  • fastest:
A
  • 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)
18
Q

types of fuel sources: total energy production:

  • least
  • intermediate
  • most
A
  • phosphagen: regeneration of ATP by phosphocreatine
  • generation of ATP by glycolysis and glycogenolysis
  • generation of ATP by oxidative phosphorylation, fatty acid metabolism
19
Q

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 ____ ____ )
A
  • quick
  • exhaustion of ATP
  • phosphocreatine
    • ATP from ADP
  • ADP → ATP + creatine (via phosphocreatine kinase)
20
Q

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
A
  • 30
  • oxidation (glycogenolysis)
  • lactate
    • G-6-P → pyruvate → lactate
    • power and muscle fatigue
  • energy
21
Q

fact of lactate:

  • corci cycle: cooperation between ____ and ____
  • regenerate ____ from ____
A
  • muscle and liver
  • glucose from lactate
22
Q

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 ____ ____
A
  • electron transport chain
  • 3 and 2
  • intermembrane space
  • ATP via ATP synthase
23
Q

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
A
  • ATP to ADP
  • NADH to NAD+
  • potential
  • NADH
  • NADH
24
Q

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
A
  • cholecystokinin (CCK)
    • increased
    • decreased
    • decreased
  • glucagon like peptide-1
    • increased
    • increased
    • increased
25
Q

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
A
  • satiety
  • cholecystokinin (CCK) postprandial
  • G-protein coupled receptor
  • satiety
  • pancreatic , bile salts
26
Q

____ a peptide secreted by stomach, acts on regions of the hypothalamus to stimulate appetite through its receptor

secretion increases:

A

ghrelin

befoore a meal and decreases afterward

27
Q

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
A
  • adipose fat
  • hypothalamus
    • inhibits
      • stimulates
  • obese
28
Q

long-term control over caloric homeostasis: role of leptine and insulin:

  • leptin:
  • insulin:
A
  • 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)
29
Q

the fed state - liver:

A
  • glycolysis
  • glycogen synthesis
  • TAG synthesis
30
Q

the fasting state - liver:

A
  • glycogenolysis
  • gluconeogenesis
  • fatty acid oxidation
  • ketone body formation (from excess acetyl CoA)
31
Q

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
A
  • ketone bodies
  • cori
32
Q

insulin deficiency or resistance can lead to

A

hyperglycemia, metabolic syndrome, and diabetes

33
Q

effects of insulin:

  1. ____ glucose uptake (muscle adipose) via ____ glucose transporter
  2. ____ glucose trapping (liver) via ____ glucokinase
  3. ____ glycogen synthesis (liver, muscle) via ____ glycogen synthase
  4. ____ glycogen breakdown (liver, muscle) via ____ glycogen phosphorylase
  5. ____ glycolysis, acetyal Co-A productiton (liver, muscle) via ____ PFK-1 (by increased PFK-2
  6. ____ FA synthesis (liver) via ____ acetyl-CoA carboxylase
  7. ____ triacylglycerol synthesis (adipose tissue)
  8. ____ gluconeogenesis
A
  1. increased, increased
  2. increased, increased
  3. increased, increased
  4. decreased, decreased
  5. increased, increased
  6. increased, increased
  7. increased, increased
  8. decreased
34
Q

effects of glucagon:

  1. ____ glycogen breakdown (liver) via ____ glycogen phosphorylase
  2. ____ glycogen synthesis (liver) via ____ glycogen synthase
  3. ____ glycolysis (liver) via ____ PFK-1
  4. ____ gluconeogenesis (liver) via ____ FBPase-2
  5. ____ FA mobilization (adipose tissue) via ____ triacylglycerol lipase
  6. ____ ketogenesis
A
  1. increased, increased
  2. decreased, decreased
  3. decreased, decreased
  4. increased, increased
  5. increased, increased
  6. increased
35
Q

epinephrine:

  1. ____ heart rate
  2. ____ blood pressure
  3. ____ dilation of respiratory passages

(increase delivery of O2 to tissue (muscle)

A
  1. increase
  2. increase
  3. increase
36
Q

epinephrine:

  1. ____ glycogen breakdown (muscle, liver)
  2. ____ glycogen synthesis (muscle, liver)
  3. ____ glucogneogensis

(increase production of glucose for fuel)

  1. ____ glycolysis (muscle)

(increases ATP production in muscle)

  1. ___ FA mobilization (adipose tissue)

(increases availability of FAs as fuel)

  1. ____ glucagon secretion
  2. ____ insulin secretion

(reinforce metabolic effects of epinephrine)

A
  1. increase
  2. decrease
  3. increase
  4. increase
  5. increase
  6. increase
  7. decrease
37
Q

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
A
  • AMP-activated protein kinase
  • high
  • low, phosphorylates
  • ATP and AMP
38
Q

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
A
  • increase
  • increase
  • increase
  • decrease
  • decrease
  • decrease
39
Q

AMPK ____ anabolism

AMPK ____ catabolism

A

decrease

increase