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GI > Intro To Metabolism > Flashcards

Intro To Metabolism Flashcards

1
Q

Devoted to the capture of useful energy from high-energy compounds, and to the breakdown of compounds to simpler constituents

A

Catabolic Pathways

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2
Q

The small molecules that are the reactants and products of a reaction are called

A

Metabolites, enzymes, and energy

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3
Q

Signal transduction pathways regulate

A

Metabolism

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4
Q

Signaling molecules become activated by modifications such as

A

Phosphorylation

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5
Q

A major role of the hormones involved in metabolic homeostasis is to maintain blood glucose levels above

A

60mg/100mL

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6
Q

It is also important that fasting glucose levels remain below

A

100mg/dL

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7
Q

The stored form of fuels, in particular adipose tissue, directly correlated with

A

Leptin and Insulin Levels

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8
Q

Sense blood glucose and use this information to regulate food intake

A

Glucoreceptors in the hypothalamus

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9
Q

Stimulates anabolic metabolism

A

mTOR signaling pathway

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10
Q

The mechanistic target of rapamycin (mTOR) signaling pathway controls

A

Metabolism and cell growth

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11
Q

Stimulates multiple anabolic pathways in the response to the presence of nutrients and growth factors such as insulin

A

mTOR protein complex 1 (mTORC1)

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12
Q

Controls a number of mechanisms involved in protein, lipid, and nucleotide synthesis to produce macromolecules required for cell growth

A

mTORC1

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13
Q

mTOR also negatively regulates catabolic processes such as

A

Autophagy and lysosome biogenesis

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14
Q

Which signaling pathway stimulates catabolic metabolism?

A

AMPK signaling pathway

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15
Q

Activated when metabolic demand exceeds metbolic supply, resulting in a decrease in the ATP/ADP ratio

A

AMP-activated Protein Kinase

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16
Q

Together, act as nutrient and energy sensors and regulate metabolism in conjunction with hormones

A

mTORC1 and AMPK

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17
Q

Metabolic pathways generate substrates that are used as post-translational modifications to control

A

Signal Transduction

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18
Q

Glycosylation, acetylation, mehtylation, and prenylation change activity, localization, and stability of

A

Target proteins

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19
Q

Also modify DNA and histones, leading to epigenetic alterations that influence gene expression and chromatin structure

A

Acetylation and methylation

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20
Q

Insulin binding to the insulin receptor triggers the PI3K/mTOR pathway, thus promoting

A

Anabolic Metabolism

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21
Q

Insulin is secreted into the portal vein, but almost half is degraded before leaving the

A

Liver

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22
Q

Serum insulin levels normally begin to rise within 10 minutes after ingestion of food and reach a peak in

A

30-45 minutes

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23
Q

Permit a rate of glucose influx that is proportional to the blood concentration in the physiological range

-In beta cells

A

GLUT2

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24
Q

The rate limiting step for glucose metabolism in the beta cell and the major mechanism of glucose sensing production of ATP

A

Glucose phosphorylation by Glucokinase (Hexokinase)

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25
Q

Inhibits the ATP-sensitive K+ channel and leads to depolarization, while also opening Ca2+ channel, leading to insulin exocytosis

A

Glucose phosphorylation by Glucokinase (Hexokinase)

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26
Q

Insulin gene expression and islet cell biogenesis are dependent on several transcription factors that are specific to the

A

Pancreas, liver, and kidney

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27
Q

Bind to K channels to block activity and promote insulin release

A

Sulfonylurea drugs

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28
Q

The most important hormone coordinating the use of fuel

A

Insulin

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29
Q

The primary hormone that orchestrates fuel use and storage during the fed state

A

Insulin

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30
Q

Insulin is synthesized in the beta cells as a prepro-hormone consisting of peptides

A

A, B, and C (a connecting peptide)

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31
Q

About 5-10% of the final secreted product is still in the form of

-no insulin activity

A

Proinsulin

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32
Q

Genes coding for insulin are transcribed to mRNA in the

A

Nucleus

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33
Q

mRNA then moves into the cytoplasm and translation occurs with formation of an N-terminal hydrophobic signal sequence that targets the nascent chain into the

A

ER

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34
Q

Further elongation of the nascent chain into the lumen of the ER results in the formation of

A

Preproinsulin

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35
Q

The signal sequence is then cleaved, forming

A

Proinsulin

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36
Q

Proinsulin is transported from the ER to the Golgi where it is cleaved, forming the

A

Insulin and C-peptide

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37
Q

Insulin and C-peptide are stored in

A

Secretory granules

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38
Q

Secretory granules are secreted by exocytosis, releasing

A

Insulin and C-peptide

39
Q

A good indicator of insulin production due to its longer half life

A

C-peptide

40
Q

Used to differentiate the cause of high insulin in patients

-i.e. increased endogenous production vs exogenous overdose

A

C-peptide levels

41
Q

Activates protein kinases such as Akt that negatively regulate repressors of the anabolic effects of insulin

A

Insulin signaling

42
Q

Repressing these factors (such as FOXO, TSC2, and GSK3) promotes

A

Glucose metabolism and the other effects of insulin

43
Q

In the liver, insulin stimulates glucose uptake by

-Leads to subsequent glycolysis

A

GLUT-2

44
Q

Once hepatic glycogen stores are replenished (80-100g), excess glucose is used for the synthesis of

A

Triglycerides

45
Q

The glucose that is not captured by the liver contributes to the postprandial rise in

A

Peripheral Glucose levels

46
Q

Refers to the ability of an individual to minimize the increase in blood glucose concentration after a meal

A

Glucose tolerance

47
Q

A primary way by which insulin promotes glucose tolerance is the activation of

A

GLUT4 in skeletal muscle

48
Q

Stimulates the translocation of GLUT4 transporters to the cell membrane

A

Insulin

49
Q

Insulin also stimulates GLUT4 dependent uptake of glucose and subsequent glycolysis in

A

Adipose tissue

50
Q

Utilizes glycolysis for energy needs, but also for generation of glycerol-3-P required for reesterification of FFAs into triglycerides

A

Adipose TIssue

51
Q

Stimulates the expression of LPL within adipose, promoting the release of FFAs from chylomicrons

A

Insulin

52
Q

Under resting conditions, Rab10 is constitutively inactivated by TBC1D4/AS160 through its

A

GAP activity

53
Q

Inactive Rab10 is then unable to target the

A

GLUT4 containing vesicles

54
Q

Upon insulin stimulation, the insulin receptor phosphorylates

A

IRS-1

55
Q

IRS-1 then activates

A

PI3K

56
Q

Produced by PI3K at the plasma membrane where it activates Akt/PKB

A

PIP3

57
Q

The activated Akt phosphorylates a variety of target molecules including

A

TBC1D4

58
Q

Phosphorylated TBC1D4 then loses its GAP activity, and thus Rab10 is activated, promoting translocation of

A

GLUT4 to the plasma membrane

59
Q

Glucagon and Epinephrine bind to

A

G-protein coupled receptors

60
Q

Epinephrine and glucagon both function to control

A

Glycogen metabolism

61
Q

Glucagon and epinephrine both trigger the production of cAMP and the activation of

A

PKA

62
Q

Has epinephrine receptors but no glucagon receptors

A

Muscle

63
Q

In the muscle, glycogen metabolism stimulated by Epi produces

A

Lactate

64
Q

In the liver, epinephrine and glucagon stimulate the breakdown of glycogen to

A

Glucose phosphate

65
Q

Represent the primary hormones that induce the mobilization of energy stores and new synthesis of glucose and ketone bodies during the fasting state

A

Glucagon and catelcholamines

66
Q

Glucagon and catecholamines also promote proteolysis and the release of

A

Amino acids

67
Q

Activation of the pituitary-adrenal axis is a prominent neuroendocrine response to

A

Stress

68
Q

Stimulation of this axis results in hypothalamic secretion of

A

Corticotrophin-Releasing Factor (CRF)

69
Q

CRF then stimultes the pituitary to release

A

ACTH

70
Q

Which part of the hypothalamus is responsible for the integrated response to stress?

A

Paraventricular nucleus

71
Q

Which three things mediate much of the neurogenic stimulation of CRF production

A

Norepi, Seratonin, and Acetylcholine

72
Q

Binds to G-protein coupled receptor to manage acute stress

A

Epinephrine

73
Q

The same signaling pathways can be used for both

A

Glucagon and epinephrine

74
Q

Epinephrine responds to

A

Stress

75
Q

Glucagon responds to

A

Low blood sugar

76
Q

Caffeine, theophylline, and other members of the methylxanthine group of compounds inhibit

A

Phosphodiesterase

77
Q

Inhibiting phosphodiesterase leads to an increase in cellular levels of

A

cAMP

78
Q

Cortisol is present in the blood bound to

A

Corticosteroid-binding globulin (CBG)

79
Q

When cortisol binds its receptor, the steroid-receptor complex enters the nucleus as a dimer and binds to the

A

Glucocorticoid Response Element (GRE)

80
Q

GH stimulates growth primarily through the regulation of the growth-promoting hormone

A

IGF

81
Q

Also has metabolic functions such as raising blood glucose by decreasing peripheral tissue utilization

A

GH

82
Q

Promotes lypolysis and thus increases the availability of glycerol and FFas as fuel for muscle work

A

GH

83
Q

During periods of metabolic demand, GH shunts the metabolic pathways from glycogenolysis to the metabolism of FFAs into

A

Acteyl CoA

84
Q

The only proglycemic hormone

A

GH

85
Q

GH directly blocks glucose uptake by skeletal muscle, and thus promotes

A

Insulin resistance

86
Q

Increase the basal rate of oxygen consumption and heat production

A

Thyroid hormones

87
Q

Potentiates stimulatory effects of epi, norepi, glucagon, cortisol, and GH on gluconeogenesis, lipolysis, ketogenesis, and proteolysis

A

T3

88
Q

The overall metabolic effect of thyroid hormone is accelerating the response to

A

Starvation

89
Q

How many types of intracellular thyroid hormone receptors are there?

A

Two

90
Q

The unoccupied thyroid hormone receptor is bound to DNA and it represses

A

Transcription

91
Q

Therefore, thyroid hormone receptor acts as a repressor in the absence of

A

Thyroid hormone

92
Q

What is the first compound common to the catabolism oarbohydrates, lipids, proteins, and ethanol?

A

Acetyl CoA

93
Q

Can humans synthesize fatty acids from glucose?

A

No

94
Q

Which 4 amino acids can glucose NOT synthesize?

A

Leu, Ile, Lys, and Phe

GI (59 decks)

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