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Biochemistry Exam III material > Integration > Flashcards

Integration Flashcards

1
Q

Central themes of metabolism

A
  • ATP is the universal energy carrier
  • ATP is generated by the oxidation of metabolic fuels
    • glucose
    • Fatty acids
    • Amino acids
  • NADPH is the redox agent for reductive biosynthesis
  • Biomolecules are constructed form a small set of building blocks
  • Biosynthetic and degradation pathways are distinct
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2
Q

What are the major metabolic pathways

A
  • Glycolysis
  • Gluconeogenesis
  • Glycogen metabolism
  • Fatty acid metabolism
  • Citric Acid cycle
  • Oxidative phosphorylation
  • Amino acid metabolism
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3
Q

Only the ____ can carry out all of the reactions of the major metabolic pathways

A

Liver

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4
Q

What are the key junction points of the 7 major metabolic pathways

A
  • Glucose-6-phosphate
  • Pyruvate
  • Acetyl CoA
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5
Q

When glucose is transported into the cell it is rapidly phosphorylated to _______, which may be catabolized into______, stored as ______ or converted into _______ by the PPP

A

Glucose-6 phosphate, pyruvate, glycogen, ribose-5-Phosphate

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6
Q

Glucose 6-phosphate can be generated form _____ stores or by ______

A

glycogen or by gluconeogeneisis

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7
Q

Pyruvate is generated from glucose 6-phosphate by ______.

A

Glycolysis

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8
Q

Pyruvate is converted into lactate under _____ to regenerate _____

A

anaerobic conditions, to regenerate NAD+

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9
Q

Lactate must be subsequently oxidized back to _____

A

pyruvate

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10
Q

pyruvate can be transaminated to form

A

alanine

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11
Q

Pyruvate may be carboxylated to form ____ in the matrix of the mitochondria, this is the first step in ____

A

OAA, Gluconeogenesis

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12
Q

Pyruvate may be reduced into ____ by the pyruvate dehydrogenase complex

A

Acetyl CoA

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13
Q

Acetyl CoA is the activated 2-carbon unit produced by the _________ of pyruvate or by the ______ of fatty acids. it may also be produced by the degradation of ______

A

oxidative decarboxylation, beta-oxidation, ketogenic amino acids

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14
Q

Acetyl CoA may be completely oxidized into CO2 via the _____, converted into _____ which in turn may be converted into ketone bodies or cholesterol. Acetyl may be exported into the cytosol and converted into _____

A

TCA, HMG-CoA (3-hydroxy-3-Methyl-glutaryl CoA), fatty acids

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15
Q

major metabolic pathways that occur in the cytosol

A
  • Glycolysis
  • Pentose phosphate pathway
  • Fatty acid synthesis
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16
Q

Major metabolic pathways that occur in the mitochondrial matrix

A
  • Citric acid cycle
  • Oxidative phosphorylation
  • Beta-Oxidation of Fatty acids
  • Keton-Body formation
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17
Q

major metabolic pathways that interplay of both cytosol and mitochondrial matrix

A

Gluconeogenesis and urea synthesis

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18
Q

____ is the primary fuel for the brain

A

Glucose

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19
Q

only under prolonged starvation does the brain use

A

ketone bodies as fuel

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20
Q

The brain has ___ capacity to store fuels and needs a continuous supply of glucose

A

no

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21
Q

The average brain consumes ____ g of glucose a day

A

120 grams

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22
Q

70% of the brains glucose intake is used to maintain

A

the Na+, K+ membrane potentials

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23
Q

Glucose is transported into the brain by the ______ glucose transporter

A

GLUT3

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24
Q

Fatty acids cannot be used as fuel for the brain because they

A

cannot cross the brain blood barrier

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25
Q

3 possible outcomes for glucose-6-phosphate

A
  • Glycogen
  • Pyruvate
  • Ribose-5-P
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26
Q

4 possible outcomes of pyruvate

A
  • Acetyl-CoA
  • Lactate
  • Alanine
  • OAA
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27
Q

3 possible outcomes of acetyl-CoA

A
  • CO2
  • Fatty acids
  • Ketone bodies
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28
Q

What is the number 1 metabolic player

A

Liver

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29
Q

functions of liver

A
  • responds quickly to dietary conditions because of rapid turnover of its enzymes
  • Processes most incoming nutrients
  • Maintains constant concentrations of nutrients in blood (e.g. via gluconeogenesis), smoothing out fluctuations due to the starve-feed cycle
  • processes toxins and wastes (e.g. through urea cycle)
  • synthesizes and secretes plasma proteins
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30
Q

Liver primarily depends on _____ of _____ for its own energy needs

A

beta-oxidation of fatty acids

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31
Q

Amino acids go directly to the liver thought the _____ after absorption

A

portal vein

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32
Q

The liver uses amino acids to make _____, for _____, for biosynthesis of nitrogen-containing molecules, or ____

A

proteins, for gluconeogenesis, for biosynthesis of nitrogen-containing molecules, or for fuel

33
Q

Adipose tissue is the metabolic _____

A

maintainer

34
Q

adipose tissue stores TAGs and releases FAs and glycerol as signaled by _____/_____

A

glucagon/epinephrine

35
Q

TAGs with c-AMP-activated and lipases —–>

A

fatty acids + glycerol

36
Q

What is the turnover of TAGs a day

A

50-60 g/day

37
Q

What is the long-term energy system

A

Oxidative system

38
Q

What is the short term energy system

A

Anaerobic glycolysis

39
Q

What is the immediate energy system

A

Phosphagen system

40
Q

What is the reaction in the phosphagen system.

A

phosphocreatine + ADP ——> ATP + Creatine

41
Q

Phosphocreatine lasts about

A

10 seconds

42
Q

Explain the reactions under anaerobic conditions

A

ATP reserves are used in about 1 to 2 seconds
Phosphocreatine lasts about another 10 seconds
next 1 to 2 minutes is Glycogen–>G-6-P —-> Pyruvate —–> lactate

43
Q

Fate of lactate

A

Cooperation between muscles and liver (Cori Cycle) to regenerate glucose from lactate

44
Q

Can the heart burn lactate

A

Yes

45
Q

Liver must use ____ in synthesis of glucose from lactate

A

ATP (think gluconeogenesis)

46
Q

Does the brain have any significant energy reserves

A

No

47
Q

The brain is dependent on blood glucose at ____ to maintain ion gradients

A

4.5mM

48
Q

The Brain uses ____% of the total O2 consumed by a resting human

A

20%

49
Q

After several _____ of low glucose, the brain switches to use of ______, which are degraded via TCA. Thus conserving the body’s _____

A

days, ketone bodies. Proteins

50
Q

What is the normal range of blood glucose

A

90-60

51
Q

Around a blood glucose of about ________ the pt will have subtle neurological signs; hunger release of glucagon, epinephrine, cortisol, sweating, trembling

A

40-55

52
Q

Around a blood glucose of about _____ the pt will become lethargic, have convulsions, and possible coma

A

30-40

53
Q

At blood glucose lower than _______ the pt will have permanent brain damage (if prolonged) and possible death

A

10-0

54
Q

The mechanical power of the heart is fueled by ____ and _____

A

fats and carbohydrates (fatty acid oxidation and glycolysis)

55
Q

does insulin inhibit gluconeogenesis

A

YES

56
Q

Insulin deficiency or resistance can lead to

A

Hyperglycemia
Metabolic syndrome
Diabetes

57
Q

Metabolic effects of insulin

A

Increase in glucose uptake (muscle, adipose)
increase in glucose uptake (liver)
Increase in glycogen synthesis (liver, muscle)
decrease in glycogen breakdown (liver, muscle)
increase in glycolysis, Acetyl-CoA production (liver, muscle)
Increase in fatty acid synthesis (Liver)
increase in TAG synthesis (adipose tissue)

58
Q

Target enzymes that insulin induces

A
  • Glucose transporter (GLUT4)
  • Glucokinase
  • Glycogen synthase
  • PFK-1 (by increase in PFK-2)
  • Pyruvate dehydrogenase complex
  • Acetly-CoA carboxylase
  • Lipoprotein lipase
59
Q

Target enzymes that insulin inhibits

A

glycogen phosphorylase

60
Q

What is the insulin receptor

A

Receptor Tyrosin Kinase (RTK)

61
Q

Insulin binding to Receptor tyrosin kinase triggers

A

autophosphorylation at tyrosine

62
Q

Metabolic effects of epinephrine

A
  • increases glycogen breakdown (muscle, liver)
  • decreases glycogen synthesis (muscle, liver)
  • Increases gluconeogenesis (liver)
  • Increases glycolysis (muscle)
  • Increases fatty acid mobilization (adipose tissue)
  • increases glucagon secretion
  • Decreases insulin secretion
63
Q

Epinephrine receptors act through ______

A

G proteins

64
Q

Metabolic effects of glucagon

A
  • increase glycogen breakdown (liver)
  • Decrease in glycogen synthesis (Liver)
  • Decrease in glycolysis (liver)
  • Increase gluconeogenesis (liver)
  • increase in fatty acid mobilization (adipose tissue)
  • increase in ketogenesis
65
Q

What is the major effect of glucagon

A

production and release of glucose by the liver

66
Q

Glucagon inhibits what enzymes

A
  • Glycogen synthase
  • PFK-1
  • Pyruvate Kinase
67
Q

Glucagon induces what enzymes

A
  • Glycogen phosphorylase
  • FBPase-2
  • PEP carboxykinase
  • TAG lipase Perilipin phosphorylation
  • Actyl-CoA carboxylase
68
Q

Glucagon receptor acts through _______

A

G proteins

69
Q

well feed muscle will

A

use glucose to make glycogen

70
Q

fasting liver reactions

A

Acted on by Epinephrine and Glucagon

  • Glycerol from adipose goes into gly-3P for gluconeogensis
  • glycogenolysis
  • Gluconeogenesis
  • Fatty acid oxidation
  • Ketone body synthesis
71
Q

Fasting adipose reactions

A

-Acted on by glucagon and epinephrine

  • TAG breakdown into FA and glycerol (FA will go to blood via albumin) (glycerol will go to liver)
  • FA oxidation
  • no glucose uptake
72
Q

Fasting muscle reactions

A

acted on by epinephrine

  • no uptake of glucose
  • Glycogen breakdown
  • FA oxidation form adipose
  • Ketone body utilization (form the liver)
73
Q

During an extended fasting state what changes from the early stages

A

Glycerol and FA are transported from the Adipose tissue to the liver. Glycogen reserves are gone so the liver resorts to making ketone bodies from FA. The muscle is stimulated by cortisol to breakdown proteins and send the amino acids to the liver. The liver uses the amino acids to produce react with pyruvate producing urea and glucose

74
Q

Alcohol fatty liver disease

A

excess energy in NADH, fatty acid synthesis DHAP (glycerol) = increased TAGs

75
Q

Energy is high when

A

High ATP, High NAD+, Low NADH

76
Q

________ is the cellular energy sensor

A

AMP-Activated protein kinase (AMPK)

77
Q

When ATP is low, AMPK is allosterically activated and

A

phosphorylates many targets controlling cellular energy production and consumption

78
Q

The competition between ___ and ____ for binding to the AMPK allosteric sites determines the activity of AMPK

A

ATP and AMP

79
Q

______ is released from fat and signals hypothalamus that you are full

A

leptin

Biochemistry Exam III material (13 decks)

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