integration of metabolism

Question 1

what organ can carry out all metabolic pathways

Answer 1

liver

Question 2

what molecules act as metabolic junction points?

Answer 2

glucose-6-phosphate

pyruvate

acetyl-CoA

Question 3

end products assoociated with glucose-6-phosphate

Answer 3

glycogen (via glycoogen metabolism)

pyruvate (via glycolysis and gluconeogenesis)

ribose-5-phosphate (via PPP)

Question 4

end products associated with pyruvate

Answer 4

acetyl-CoA (via pyruvate dehydrogenase)

lactate (via lactate dehydrogease in exercising muscle)

alanine (via transamination)

OAA (via TCA cycle)

Question 5

end products associated with acetyl-CoA

Answer 5

CO2 (via TCA cycle)

ketone bodies (via ketone body metabolism)

fatty acids (via fatty acid metabolism)

Question 6

preferred energy source of red blood cells

Answer 6

glucose

Question 7

preferred energy source of brain

Answer 7

glucose

ketone bodies

Question 8

prferred energy source of adipose tissues

Answer 8

glucose

fatty acids

Question 9

preferred energy source of liver

Answer 9

fatty acids

Question 10

preferred energy source of muscles

Answer 10

glucose

fatty acids

amino acids

Question 11

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 ____

Answer 11

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

Question 12

adipose: the main assist:

• synthesizes and stores ____ as signaled by ____ (fed state)
• releases ____ ____ and ____ as signaled by ____/____ (hunger, exercise)

Answer 12

• triacylglycerols, insulin
• fatty acids and glycerol, glucagon/epinephrine

Question 13

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

Answer 13

• reserves
• glucose
• 20
• ketone bodies
  
  • TCA cycle
  • protein

Question 14

heart:

• cardiac muscle is exclusively ____
• ____ , ____ , ____ ____ , and ____ ____ serve as fuel
• no ____ stores
• lack of O2 leads to tissue death ( ____ ____ )

Answer 14

• aerobic
• glucose, lactate, fatty acids, and ketone bodies
• glycogen
• myocardial infarction

Question 15

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

Answer 15

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

Question 16

energy systems

ATP/PCr system =

anaerobic glycolysis =

oxidative system =

Answer 16

immediate

short-term

long-term

Question 17

types of fueld sources: speed

• slowest:
• intermediate:
• fastest:

Answer 17

• 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)

Question 18

types of fuel sources: total energy production:

• least
• intermediate
• most

Answer 18

• phosphagen: regeneration of ATP by phosphocreatine
• generation of ATP by glycolysis and glycogenolysis
• generation of ATP by oxidative phosphorylation, fatty acid metabolism

Question 19

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 ____ ____ )

Answer 19

• quick
• exhaustion of ATP
• phosphocreatine
  
  • ATP from ADP
• ADP → ATP + creatine (via phosphocreatine kinase)

Question 20

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

Answer 20

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

Question 21

fact of lactate:

• corci cycle: cooperation between ____ and ____
• regenerate ____ from ____

Answer 21

• muscle and liver
• glucose from lactate

Question 22

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 ____ ____

Answer 22

• electron transport chain
• 3 and 2
• intermembrane space
• ATP via ATP synthase

Question 23

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

Answer 23

• ATP to ADP
• NADH to NAD+
• potential
• NADH
• NADH

Question 24

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

Answer 24

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

Question 25

_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

Answer 25

* satiety * cholecystokinin (CCK) postprandial * G-protein coupled receptor * satiety * pancreatic , bile salts

Question 26

\_\_\_\_ a peptide secreted by stomach, acts on regions of the hypothalamus to stimulate appetite through its receptor secretion increases:

Answer 26

ghrelin befoore a meal and decreases afterward

Question 27

_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

Answer 27

* adipose fat * hypothalamus * * inhibits * stimulates * obese

Question 28

_long-term control over caloric homeostasis: role of leptine and insulin:_ * leptin: * insulin:

Answer 28

* 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)

Question 29

_the fed state - liver:_ * * *

Answer 29

* glycolysis * glycogen synthesis * TAG synthesis

Question 30

_the fasting state - liver:_ * * * *

Answer 30

* glycogenolysis * gluconeogenesis * fatty acid oxidation * ketone body formation (from excess acetyl CoA)

Question 31

_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

Answer 31

* ketone bodies * cori

Question 32

insulin deficiency or resistance can lead to

Answer 32

hyperglycemia, metabolic syndrome, and diabetes

Question 33

_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

Answer 33

1. increased, increased 2. increased, increased 3. increased, increased 4. decreased, decreased 5. increased, increased 6. increased, increased 7. increased, increased 8. decreased

Question 34

_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

Answer 34

1. increased, increased 2. decreased, decreased 3. decreased, decreased 4. increased, increased 5. increased, increased 6. increased

Question 35

_epinephrine:_ 1. ____ heart rate 2. ____ blood pressure 3. ____ dilation of respiratory passages (increase delivery of O2 to tissue (muscle)

Answer 35

1. increase 2. increase 3. increase

Question 36

_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)

Answer 36

1. increase 2. decrease 3. increase 1. increase 1. increase 1. increase 2. decrease

Question 37

_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

Answer 37

* AMP-activated protein kinase * high * low, phosphorylates * ATP and AMP

Question 38

_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

Answer 38

* increase * increase * increase * decrease * decrease * decrease

Question 39

AMPK ____ anabolism AMPK ____ catabolism

Answer 39

decrease increase